Intake plenum and 911 throttle body - Page 9 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Hi ! So here it is, finally available! A cheaper solution than the IPD, and better looking with a cleaner fitment than the 996 plenum. First, let me clarify what it is and what it does: This is a replacement intake plenum for all 986 boxster 2.7 and 3.2L , it allows the use of a 996 (or 997) Throttle, which has a larger diameter (74 vs 68mm), which in turns improves the amount of air flowing into the engine. Here you can see the size difference! The 986 TB fits INSIDE of the 996 TB! It is made of nylon plastic, which is resistant to oil, fuel and most solvent, and also quite strong (I can stand on it). It is not as stiff as the materiel used for the original parts, why is glass fiber reinforced nylon, hence the need for the stiffening ribs. It is not molded, but made by Selective Laser Sintering , which is a 3D printing process that creates a part really homogenous inside, but with a rough surface. Far superior compared to the Fused Deposit Modelling used by all the "cheap" 3D printers. Why not making it out of aluminum or have it molded in a superior material? Simply because of the cost: I would need to make a lot of them to be able to sell them at the same price. Also, aluminum conducts heat better than nylon, which is not ideal for an intake system. Why not use a Y shape? The Y shape is patented by IPD, though there are ways to go around the patent, I'd rather keep the T shape and sleep in peace! Why is it white inside? I receive the part white, then paint it black with epoxy paint. I don't paint the inside so there is no risk of the paint being dilluted by the oil and gases coming from the crankcase ventilation then going through your engine and clog something. What's included? What you'll receive are: -The new intake plenum -Bolts and nuts for the TB -A piece of hose for the crankcase ventilation (AOS connection) -An EZ-coil to prevent the hose from collapsing. -2 hose clamps What else do I need? To simply fit the plenum, you'll need: -A 996 or 997 non-GT3 Throttle body (a used one is acceptable) -A new intake tube, I'll discuss that later. -RTV sealant to seal the TB on the plenum, it is a cheaper and more reliable method than using the 20$ Porsche rubber seal. /!\ I don't recommend this as the first modification to your engine, alone, it won't performed at it's full potential. You need supporting mods: at least a K&N drop in filter, and a modified exhaust. What results to expect? I can only speak for myself, but there is a lot of feedback page 17. I found a noticeable increase in torque above 1800 rpm then a flatter torque curve to redline, with less fading around 7000rpm. The torque dip around 3000rpm is greatly reduced. It makes the car a lot more enjoyable for every day driving. The sound changes too, the intake sounds deeper and louder. I'll complete the thread when I have more time with the intake tube parts, more pictures, and installation tips. You can always PM me Ben

I'm interested when you are done testing !! If you are looking for a tester I have a 986 that I installed a 3.4 996 motor. Goes like hell !!! Let me know. Thanks for the work !!

Thanks what throttle body you have on the 3.4 ? I can make the same for any sizes of TB. !

Very interesting! Addresses the inside corner flow issue, bound to be both lighter and a better value than the current aftermarket offering in aluminum. Keep us posted please as development proceeds!

The wedge doesn't make a big difference, but the Y shape does. http://986forum.com/forums/268415-post22.html From this thread. http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-2.html Most people just go with the 997 Distribution T because it has a very good Y shape to it. If you can beat this price for a new 997 Distribution T and add more Y shape to it, I might be game on yours even though I already bought the piece. 99711041603 - DISTRIBUTOR TUBE - ES#1498085

I won't beat the 54$ price you show :/ I didn't know that the 997 T worked for the 986 ! But I can improve even more the design, I will work on a more "Y-ed" design, to see what I can do

yup - hard to beat the price on the 997 part. however, that's for the 76mm tb; the only guys who make something for the 83mm gt3 tb are ipd, so if you can make something cheaper than them you will have an immediate market.

I have a 74MM throttle body. How hard would it be to put a slight turn on the main intake port like stock Boxster TB have? That would really be helpful with the tight fits you end up with when installing a 996 motor in the Boxster motor bay.. If not I am still interested in the straight T you show below. Ben, I am guessing you are doing this with a 3 D printer....Correct??

Subscribed! Ben, what is you background? What got you started on this project?

Reebuck, can you show me how your engine bay looks ? i can make any design for any size of TB it's made in nylon by stereolithography (the parts are more accurate and stronger than with the "hot wire deposit" 3D printers). My background ? I'm an currently studying auto tech, and love the process of designing, making and testing things related to cars as far as my wallet allows me

hey ben - i'd like a plenum for a gt3 (83mm ID) tb - what dimensions do you need? I can get you ID and OD for the tubes that attach to the manifolds, distance between the two manifolds, ID of the throttle body, and details on the flange that fastens the tb to the plenum (hopefully it's standardised for all tbs). I would like as large a radius as possible on the bends - I can determine what length of plenum my engine bay can support.

Ben - you're pretty much making one of these if I understand correctly: TechnoTorque Do I have that right? I have a stock 2000 Boxster S, don't know what my plenum dimensions are - is that all you need to build one?

No, these retain the stock TB but add a "divider", the first purpose of my is to use a bigger throttle body. I took the measurement on my boxster 2.7 wich share its intake with the 3.2, so I already have the measurement. I can make it any way you want, straight T, with a little turn, divider, no divider, wright anything on it ... etc

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Ah, got it. Well, good question. I don't know what I don't know on this. "A larger TB with better air flow" does sound good. I don't know if that translates to as to turns, dividers, straight, etc. What are you recommending for increased performance? King, you seem to know a bit about this, what is you take? :-)

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The TechnoTorque is a larger intake tee with a larger throttle body than the OEM. Happy Boxstering, Pedro

Sorry I didn't know that they had the larger TB too.

Very interesting. I think a 1 piece tube from MAF to new TB could be desirable as well. I have a 911 TB and 997 plenum in my garage, just have to get time to cobble the rest together. My school (UTA) just opened a FabLab, gonna go learn how to use the 3D printers tomorrow night. Won't be at your level, but this definitely makes me more excited to go learn.

The problem is that the tube will cost more than the T itself :/ Great to have a fablab ! We don't in mine

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I didn't figure you could. What I would focus on is getting the Y shape better then the 997 piece, if possible shorten the distance from the TB connection to the Distribution T. On the 997 part it puts the TB very far out. I would probably forget about the wedge too. This is what I would want for a Distribution T that accepts a 76mm TB and has the same diameter tube as the plenums. One of the problems with the 997 piece is the larger diameter tube, which also pushes the TB further out.

Look at the Y on this baby. Figure out how to do this. [IMG]http://www.****************************************************.com/mm5/graphics/00000001/991%20911%202014%202015%202013%20porsche%20carrera %20ipd%20plennum%20plenum%20performance%20air%20in take.jpg[/IMG]

If you want a good Y shape, you have to have the TB pushed out, i'm working on a new one with a Y !I can't have a Y as large a the one you're showing in the bottom because the space is not wide enough on the 986. The wedge stabilises the air, maybe the cfd testings of the T alone don't show a big improvement with the wedge, but once on the car with the whole system, it should make a bigger difference. You want the flow as clean as possible all the way to the valves (the you want turbulences in the combustion chambers). In a naturally aspirated car, every bit counts I have my midterms next week so I have to study and will not have too much time to do it this week, but after I will have all the time I need !

I think the reason the wedge doesn't help as much is because the wedge actually makes the inside circumference of the tube smaller and less air can get through. Keep at it! I would like to have one with matching tube diameter to the plenums. The 997 has an OD of 97mm. Much larger then the Plenums opening.

i personally think reducing the turning radius of the air ('improving the y shape') is the primary benefit so that the air can adhere as it turns the bend, which will reduce resistance and increase flow volume. at steady-state flow an area of turbulent air is established where the wedge sits, and turbulent air has less flow resistance than the wedge does, so the wedge is not much of a benefit. HOWEVER, the flow through the intake tract isn't steady state. it pulses with opening and closing of valves, so the turbulent air wedge is constantly re-establishing itself. in this instance having an actual divider may be of some benefit. unfortunately, the previous offerings available to us were a bit expensive ($260 for pedro to add a wedge to a 997 plenum, or $900 for an ipd unit). further, if the wedge isn't done right, as kram says, it probably does more harm than good as it becomes a restriction to flow. ps, not arguing against Pedro's claimed gains from the technotorque, nor that his pricing is unrealistic, but am wondering how much of the gains he shows are from the 997 plenum vs the added wedge - that would answer the question.

More inspiration lol. Werks1 - Porsche 997 Carrera/Carrera S Carbon Fiber Plenum

I'm taking your comment in account for the next shot With the design I have now, the air stays attached to the plenum as it turns (well, just by blowing on it you can feel that the air stays attached to the inside, my test worth not that much but I'm confident ) And the roughness of the material help with that too !

Any concern about nylon contracting when it gets hot?

nope, the temperature will not rise above critical level for this part, and if needed, a heat shield can easily be wrapped around for protection ! We will see, that is why I want to test it before anything else !

Here, look at how this is done. From the TB point the section goes all the way to the top and to the side. No T shape to it at all. This is what you should shoot for. Get rid of the tube to tube design. Actually I would call this a V shape more then a Y shape. [IMG]http://www.****************************************.com/Images/93174-3.61.jpg[/IMG] Just need it to have the same OD/ID where it meets the stock Boxster Plenums and accepts a 76mm TB. This picture is for a 996, but it only accepts a 74mm TB.

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Whose engine bay is this? I would like to see your intake pipe arrangement..

That's BYprodriver's engine bay. I will have mine installed in the next 2 weeks, still waiting on a couple of parts to come in, but have my 987 air box modding done. http://986forum.com/forums/437845-post182.html

I'm working on it Also, I made a heat resistance test today, I bake the T in the oven at 190°F (a temperature that it will hardly see in real life) for 2 hours, after that I tried to bend and compress it, but it held just like when at room temperature So I have no worries at all for the heat now.

When will you be ready to make the 74 mm intake??

Well, I have yet to receive the hardware et test it on the car :/ the problem is that some supplier are very slow... I think I will switch from metric nuts and bolts to inches so I can find the hardware easily. as soon as I validate the part and the reliability I will make some for the others

new shape for the 76mm and for the 83mm I don't think I can get more angle in the V without sacrifying the smooth transition between the tubes.

Looks nice! When do you think you will get a test in on one?

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Not sure if you're keeping a list, but I'm interested in your design. I also have a 2.7 liter Thanks, Brett

For now the list is this thread I'm still waiting for some hardware (from various places, to see wich one will be the best, that's why it takes some times). Ben

Hi ! Two more parts to get and I can test the T ! I can't wait ! The nuts fit in as designed I will test it on a dyno the 11th of ... April ... It's a month to wait, but it's the only time I can dyno it. during my school car show !

Anymore pictures to share? I'm very curious on what you have going on. I need a different distribution T and the 997 Distribution T is too big, it also has this thick piece I marked in red that hits the top of my starter and I can't get a good down angle on the TB. I really don't want to change the intake as the car is running like a beast right now. I suppose I could take it back out, shave off that area and reinforce it by melting some wire into it. .

now I'm stuck on the testing because I have no place to work :/ I don't need to do much, but I can't do it at home because my 93YO neighbour will report me for doing so ... Monday a friend should lend me is garage for few hours and I will finally get this thing done ! The only thing I did is a little sanding to smooth the outside and got the EVAP port enlarged a little. I hate wasting my time like that, waiting. If anyone want's to offer me a little clean place to work at for a few hours, he's welcome

This is an interesting thread. Being that I have a non e-gas model the only way I can find to get a larger throttle body is the Pedro's bore service. His site says they bore the stock one out to 75mm. So if I do this I would be in the market for one that would fit that. Is that a possibility?

Non e-gas 3.4 911 throttle body.

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Thanks edc, I was thinking this would work as well. But I was unable to find one online last night to be sure.

Kram36....What size engine are you running?? 996 3.4 or 3.6?? and what size throttle body are you using?? Thanks....I too am waiting to see how Ben does !!

Yes I can do one for the 2.5 too, but since the 2.5's plenum is very different from the 2.7 and 3.2's plenum I will need to take the mesurement from a 2.5L one My friend told me Monday, I hope I will be able to do it and that all my measurement were right ! cross your finger with me

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Stock 3.2, 76mm TB.

Hi ! As planned I found a garage Monday to finally work on the intake ! and... it doesn't fit ... nothing bad, but the straight T shape makes the TB bump against the starter and force the intake elbow to stick too far up. Nothing that a slight angle can't fix I will make another one soon. I also noticed that the temperature in the engine bay was higher than I thought on a hot Florida day ! So I put the T back into the oven to see if it can handle 240F ... result, it can I will just make it thicker in some place for added strengh and peace of mind ! It takes time, but I'm on the right way Ben

I also think that I will try a flow divider like in the 987 : without the flap, but it's a great way to ensure that both sides receive the exact same amount of air despite having to make a tighter turn on the left side !

Curious why the air is making a tighter turn to the left side?

because I'm not going tu use a straight T shape any more, it will be tilted 10° I will show you as soon as I'm done with the software. The shape will look weird, but I'm trying to direct air equally on each side, not that easy ... I'm going to try another route, like the oem (longer tube after the TB), and see if I can come up with a better, more balanced shape also, the problem with a big divider is that it's going to "seal" the to banks from each other, and makes you loose top end power (sorry, I lack technical vocabulary to explain it correctly in english). So ... I'm working on it If anyone has any idea, feel free to share Ben

TRK (The Radium King) would probably be the one to consult on that.

Hi ! I made modifications to the T, with an angle, the TB should point slightly to the left. this way it should clear the stater solenoid. Now I need to see if the engine cover will clear the intake elbow. I want to get it 100% right before printing it.

Remember, the short radius is what matters with any normally aspirated engine. I see people wasting their time with induction components, because they don't understand how dry flow really works.

Yep But the space is tight, and the TB is really bigger than the 986 one, so I try to find the best shape with the room I have.

Hi ! I did have a lot of free time to work on the intake, but I think this time I'm good ! I realise that trying to make it simple in shape ... would making it harder to fit ... So I copied the stock shape. It took me some time to get the angles as clos as possible to the stock T, but I think I'm close. This way, It will clear the starter solenoid, and the engine cover tell me what you think Ben

Great Ben!! When will you be able to make a few?? What material will you use (heat sensitivity)?

I will make one, test it, then, I can make as many as I want with a 2 week delay between the material will be nylon, I tested it up to 240F without problem so I'm not worried about it, it will be 4mm thick (3mm for the one I already have, and tested) and I will wrap it with heat insulator for further protection Ben

Nice design! Has the bend to the left been designed for use of the stock 3.2 intake pipe? Does have it have captured nuts as would be found in a stock piece? 74mm TB? The material also needs to be impervious to oil..

The material will resist to oil and fuel I don't know yet wich intake pipe will fit. I tought the 3.2 used the same 68mm TB as the 2.7 ? The nuts are hold in place in four hexagonal holes in the back of the mouting part. Ben

Hi ! Finally, after tens of hours behind the screen and in my engine bay, I think I have the right shape ! It has the same angle that the stock one has, so it must clear everything in the engine bay, it has the largest radius possible without affecting the fitting (larger the the stock one). I added two ribs on each side to have a better sealing with the boots. A groove in the mating surface to make applying silicon sealer evenly (I tossed the idea of using the Porsche seal, it's going to be just as good, but 4 times cheaper to make and change (20$ for the OEM TB seal...)). I tilted the EVAP connector to be as close as possible to the stock location (do you know where I can get a new hose for this ? mine broke ...) It's also 1mm thicker that the first one I made, so even stronger and resistant to heat (I will wrap it in heat shielding tape anyway). It won't be black as the first one, but white. Why ? cheaper, and it's not the same black as the stock parts so ... Finally, for information, nylon as been used for timing sprocket on some OHV engine, so in the engine bloc heat ! I think I will be safe in the intake Oh and, it does not have the wedge but I can easily make one with a wedge ! Ffffff I'm really stressed to now if all my measurement are right ^^ Ben

Ben, buddy, pal, how much will one cost me?

around 300$ shipped in the US. I will also design one for the 83mm TB soon. It's not "cheap", but still a fraction of what an IPD costs, and the benefit of having the same shape as the original one. It will also depend on what I will use for the intake tube and if I include one or let you decide ! So I can't tell you a definitive price right now, but it will be around that. Once I will have the actual parts in my hands, then installed in my car, I will be able to be more accurate Ben

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Yes you are correct. I am just hoping for/to: use the stock 3.2 intake pipe with and adapter on the end along with a 74mm TB; outlets matching the intake plenum dia.; an AOS port that matches the stock location, so that a stock AOS hose can snap right in. your angle looks pretty close to stock so the stock pipe looks promising....trust me when I say that this will be a big plus. You could just 3D scan the stock pieces and then bring them into your software, modify to suit a 74mm TB...optimizing bend radii where possible....hmmm sounds like a business op

A laser scanning tool costs more than my car ^^ But I don't need one If I had the plenum out of the car (I should have bought an used one... but didn't want to spend too much money, and at the time, I thought that a straight one could fit ...) I could have easily replicate one :/ the stock 3.2 and 2.7 intake pipes are the same too, right ? problem is that the diameter start to decrease immediatly after the MAF from 76mm to ~70mm at the TB. But I will figure it out The outlets are the same diameter inside (1mm more outside, with a taper to slide them easily into the boots). for the AOS, it should clip back on without problem (the only problem is the plastic hose is easy to break). So I think I'm pretty close to your requirement

Hi ! after months of designing and two weeks of waiting ... here is the plenum The added thickness made it really stiffer I can't test it immediatly, my instructors at school want to see it ! and my CEL is on... so it doesn't makes sense right now. so end of next week for the results But I am really confident with it ! Ben For the intake tube, I think I'm going to try the AirAid UBI kit

Looks very nice!!

So this is similar to what Pedro sells ??

thanks Here's more As you can see, I quite nailed it I'm pretty proud of my self here, as replacating a part that complicated without having it with you is quite hard ! and even better... the evap hose clamp right on the new plenum ! (I will have to move the connection a little for the next ones, but it works !). also, if you need another proof of the strengh of the part, I tried to stand on the old one... and it held my 175 pounds I still have few more test to do, but I stay confident !

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similar to the technotorque and IPD plenum and every other ones yes. but it has the shape of the stock plenum, and retaine the stock evap hose (from AOS and plenum) and boots, just needs a new intake tube

Are you 3D printing these or 5 axis or ?

3D printing!

How much are they going to cost ?

Will you be testing this set up on the dyno? You mentioned testing in a week.

I am impressed. Good luck with your CEL. They can be a PITA. I might be interested in buying one from you if/when they become available although I already have a 997 Plenum. Your design will get the throttle body a little lower and my intake setup cleaner.

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As I say on the top of this page, around 300$, but I will depend on wethet I need to paint it or not I will try to get it on the dyno, but I can't garantee it :/ The testing will be more about reliability. I will put it on my car, and abuse it, then take it off and see if there is any problem. Then, if I decide that it's good, you will get some I hope the sensor was the problem, will see next week if the CEL comes back. Yes, the TB will sit at the stock location Ben

What size TB will you be using? Stock 996?

yep, stock 996 TB, way bigger than the stock 68mm. The 83mm is a bit expensive for me ... but I will make the plenum for too

What is the size of the stock 996 TB?

74mm at the plate 76mm at the largest. The stock TB fits inside the 996's !

WOW! We need more air. Will yours be a direct fit, basically plug and play with the 996TB? Add a 987 airbox and we are in business?

Well, yes it will be a direct fit, but you will need a new intake tube, I'm working on that part too My cel went one again ... so, I have a vacuum leak somewhere... and I think I know where ... that AOS vent line must be cracked again ! So, that makes me question the fact that we should keep it, or replace it with a standard piece of hose... Because everyone will break it during installation, so why bother ? heliguy, where are you from ?

I'm in Destin. How about you?

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Not quite. You will need to use the MAF housing from your 986 air box. So, you need to figure out a way to plum your 986 MAF housing into the 987 air box.

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Nice ....so stock plenum boots can be used as the tee diameters match the plenums? This is a major potential loss area when using the 997 diverter tee. If it puts the tb in the same you might be able to work with the stock 3.2 intake tube ....modified get the end

As I said, the stock intake tube can't be reused, its tapered all the way, starting from the MAF housing. so you will not get the full benefit of the new TB. Heliguy, I'm in Delray Beach, not very close ^^

Not close at all.

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I don't see where the 997 Distribution T being larger then the plenum openings would be of any hindrance to the air flow. I used the stock plenum boots, no problem using them.

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There is a rapid section change from the outlet diameter of the 997 diverter tee to the 3.2 inlet plenum diameter. Inside there is an exposed plenum entrance edge created by stretching the stock boots to fit the 997 diverter tee larger diameter. In 3d one could visualize this as a v-section ring disrupting airflow over it. Section changes and edges generally result in flow losses in closed piping. This is why I am hoping that Ben has matched diameters....Ben can you verify explicitly? Of course these assumptions have to be verified with flow testing. Torque power and throttle response being the goals.

You are right! And yes, the diameters match with mine

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When I installed the 997 Distribution T, it was fitting right against the Plenum opening. I don't think there is a gap there to create a V and disrupt the air flow. Also going from the larger to smaller opening could increase the air velocity. Maybe The Radium King could give some better insight on this.

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"Right against" sounds like the worst condition. Essentially you have a small pipe inside of a large pipe with flow going to and into the small pipe. The flow hits the edge of the small pipe. This arrangement is covered by the boot. Sketch it out and you will have it An increase in velocity may be good here but in this case it is accomplished in an abrupt turbulent fashion which is probably not beneficial to efficient cylinder filling....it all depends on the whole system. Bens design would accomplish this velocity incease in a gradual non turbulent fashion which could help cylinder filling. There would also be less stress placed on the boots with an equal diameter arrangement. The spatial restriction imposed by the large 997 outlets is also eliminated.

Have you installed and tested it yet?

didn't had the time yet, with the shifters, school, and the friends that I have over at my place :/ I should have time next week if I can take care of the shifters fast enough

What shifters are these you speak of?

http://986forum.com/forums/diy-project-guides/54726-ball-bearing-short-shifter.html

The 997 T still has the same inherent issue with turbulence Newton' laws of physics which apply to air as well as solid matter. "An objects in motion stay in motion until acted on by an opposing force" The air entering the T will for the most part continue in the direction it is traveling towards the back of the T. "Every action has an equal and opposite reaction" The air striking the back of the T will rebound into the air stream causing turbulence. Bens design Pedro Techno Torque 1 and 2 and IPD are better solutions. The incoming air hits the flat back of the stock T and compresses before it move sideways causing not one but three turbulent areas one in the back high pressure and on the top where to low pressure accumulate at the radius to the inlet to the two exits. There are Cad test drawings showing how ineffective this is in one of these threads. Pedro system the cheapest alternative. adds a deflector V in the back creating an actual flow Y. IPD all aluminum design is molded with the same V diverter Bens is a copy of IPDs design, which I doubt he will be allowed to sell due to patents from IPD. In the end there is about a 25% improvement in this design you can't get from the stock distribution T. Look at the video from about 7 minutes in https://www.youtube.com/watch?v=B-fXau-xWO8 The negative on IDP is the $795 price opposed to Pedro's or Ben's design. note the IPDs design is the same and it totally coated in epoxy inside. https://www.youtube.com/watch?v=SneTb8-cHbo I doubt anyone who has one of these designed systems would ever go back to the factory Distribution T.

thanks for the explanation! The patent IPD has is about the diverter inside and the Y shape, I chose not to use it, I'm using the stock design, improved with larger radius. Ben

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Our engines don't work like that. Our engines pull air into it, that's the force acting upon the direction and travel path of the air. Pedro blows air into the Distribution T, which will hit the back of the Distribution T and the wedge would have a nice impact on the way the air travels. Our engines pull air in and it rides along the side of the Distribution T. That's why the Y shape is very important and having the wedge is not. http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-2.html

I didn't read everything because I'm on my phone, but pulling air and pushing air is the same. The engine does not pull air into it, the air is pushed inside because the atmospherique pressure is greater than the pressure inside the combustion chamber.

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Exactly right, the same follow equations apply for compressed air pipe and vacuum pipe. The important thing is maintaining a constant surface cross section. The Tee even with an improved inlet radius can't do that. The turbulent area in the back of the tee is affected by flow velocity increasing in size. The higher the flow velocity the smaller the effective cross section.

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Yes, that's the principle of why air wants to "move into the engine", but the engine is working like a pump too. The downward stroke of the piston with the intake valve open creates a pull on the air into the cylinder. The rings on the piston are just as important to filling the cylinder with air as it is to the compression of the air.

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So exactly how are air molecules joined together such that one can pull another? Little strings? High pressure pushing into low pressure is intuitively obvious, but low pressure "pulling" in high pressure? Puzzling.

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The instant the air starts to move Newton's laws apply. It doesn't mater if it suck through a pipe or push through a pipe the same principles apply. The same equations are used to calculate flow loss, flow velocity. This must be another theory that doesn't apply and can't be taught in Kansas school.

An engine is basically a pump, but the the air behave the same if you move it by droping the pressure on one side, or raising it on the other. There is no such thing as vacuum, it's just a difference of pressure and that is what move the air, a fluid is never "sucked" it is always pushed from an area of high pressure to an area of low pressure.

Air and water are Newtonian Fluids. A Newtonian fluid is any fluid that follow the same characteristics as a solid. Flow and velocity are base on friction and static attraction or a coefficient of viscosity. The calculations say ignore a negative number such as pressure because the value are squared so a negative pressure times itself is a positive value.

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Explain why on these charts the wedge makes no difference and in Pedro's video it does and he calls it pulling air and says there is an influence on the air We have this. "A third factor in manifold vacuum is engine compression. If an engine has low compression in all cylinders, it creates a steady, but low, manifold vacuum. If an engine has low compression in one cylinder, manifold vacuum will be low only during that cylinders intake stroke . This will be observed as a gauge that fluctuates or quickly changes reading. Low compression in a cylinder can be caused by leaking valves or rings, leaking head gaskets, or other ways that keep the cylinder from sealing during the compression stroke." Compression and Vacuum Do you know how to have a conversation without insulting someone? If you can't, you can go you know what yourself. Also read my location again smart guy, I don't live in Kansas.

I give up Believe what you want. Sarcasm Republican legislator from Missouri, offered a bill last month that would allow parents to pull their children out of high-school biology classes lest they be exposed to the concept of natural selection. Nearly 90 years since the public trial of John Scopes, a young schoolmaster accused of teaching evolution to Tennessee children, Missouri’s House Bill no. 1472 The earth is flat and Einstein was all wet

I can see a wedge helping where you have the airflow motive force being dominated by constant "push" forces as would be present from a turbo or supercharger. The reason being that side to side pulses or draw into the engine from left to right, right to left plenums are fed positively from the turbo or super charge. The side to side pulse is not disrupted by the wedge. When we consider NA there will pulses from plenum to plenum as the engine draws air in. This will be interrupted by the wedge. There is no positive charge to help feed this need. Have a look at the IPD wedge. In many iterations you will see holes, relief features which I believe is a feature intended to mitigate this NA flow issue. NA engines: wedge value is questionable Boosted engines: wedge could help cylinder filling > as always testing is needed to know

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It's not what I believe, it's what I see. With the simulations the wedge makes no difference, then you have Pedro blowing air into the Distribution T and it makes a difference. So what is it that's making this difference? It has to be the way the air is being fed into the Plenum from Distribution T. The air is not hitting the back of the Distribution T (yes maybe a little), it's getting pulled along the side of the Distribution T's radius. That's what makes the 997 Distribution T so effective.

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I don't know James. How is dirt pulled into your vacuum cleaner? Is each piece of dirt attached to each other with a little string such that one can pull another? Gravity is pulling the dirt down to the Earth, but the vacuum has enough force to pull the dirt off the ground. The force of the piston can not move air? I'm not a scientist, maybe I shouldn't comment on anything since I'm not. I'm just trying to help out. All I know is the simulation of the air flow through the Distribution T is not like putting a leaf blower in the end of the Distribution T and blowing air at it. There seems to be a difference in what our engine is doing with the air and what the leaf blower is doing with the air. Maybe you can clear this up? Is the simulation incorrect? Help out if you know, throwing jabs at me doesn't help anyone.

As an engineer, it's entertaining to watch the other engineers try to explain technical principles to non technical folks. Without a technical education folks will believe what they want to believe (suction is a great example). At some point you just have to say, "I can explain it to you, but I can't understand it for you."

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I like that

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I don't see where you explained anything? Try me, I'm not afraid to learn. From the simulation. "The volume flow rate results show that the T and T with wedge have almost identical flow rates." Yet Pedro's video shows the opposite. jsceash can you explain this? Is the simulation wrong? Did Pedro sneak a magic trick in on you? I can't imagine Pedro could pull one over on a smart guy like you.

I'll try a different way. Have you ever gone fishing in a trout stream and watched a bend in the stream with a back eddy. The water spins backward and slows as it gets away from the current the speed up as it comes back around. A portion of the stream flows back continuously. It really obvious if there is a can or foam cup floating in it. That is what happens in the long radius flat back Porsche Plenum. Now imagine the same stream and same bend if someone built a concrete barrier in the outside radius. The water would glide past at a faster speed or equal to the rest of the stream current. The IPD and or Pedro's Plenum. Pedro's video is a bit of truth a bit of exaggeration. It exploits the defect in the stock plenum. The dead space becomes larger as the velocity of air is increased it is a principle in air flow called a "Boundary air layer". "Turbulent boundary air" is proportional to the air velocity so the turbulent area increases as the air velocity increase. Pedro uses a vacuum to blow air in the plenum which creates a higher velocity than the NA motor can produce but it is fast enough to exaggerate the flow problem. I've been trying to explain all day that turbulent air is like a plug reducing flow. The second type of boundary air layer is "Laminar Boundary air" its the drag created from the air friction with surface of the pipe. This is proportional to the square root of the velocity so it increases slowly as the velocity increases so it has little effect in the application. The big thing you see this affect is golf balls put dimples in the surface you can defeat the effect. Pedro uses a Teflon insert which has a low friction coefficient. IPD used of epoxy coat them but now the shot peen the inside so it like the dimples on a golf ball either way they negate the effect at the air flow speeds for the application

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This is going to be technical. Sorry, it has to be. The answer is recirculation. The slow moving air that naturally forms the wedge forms a high pressure zone that diverts the incoming flow. As Newton or more precisely Navier-Stokes would tell us is that the path of a fluid particle is influenced by the forces on that particle. The high pressure of the stagnated wedge diverts the streamline of air away from the back of the "T". So the air coming in from the throttle body never "bounces" off the wall. The effect of a physical wedge is more likely to disrupt the secondary pulsation supercharging effect of the tuned plenum than it is to help bulk flow in any way. A simple flow bench test will prove this out. I know people like to refer to detached flow as "turbulence", but it's really not accurate (It's one of those things that annoys a fluids engineer). In reality, most flow through the engine is turbulent, which means that the air particles within the freestream is not generally taking a linear path. There is more energy in a turbulent flow, which helps keep the freestream attached to a surface. This is why they make airflow turbulent at the leading edges of airplane wings with little triangles and golf balls have dimples.

Wow, you haven't posted here in over a year blue2000s. Thanks for the explanation. So what is it about the radius that makes it flow 30% better? Does the larger radius give the air more room to move inside the Distribution T because it's already making it's own natural wedge which would reduce the area for the air to flow? Yeah, me thinking the engine was making the air pull to the radius looks really stupid, well at least to you guys lol. I never thought about the air creating it's own wedge and I'm trying to figure out why this air is following the path it does in your simulations. Also what about the 997 T being so much larger then the Plenum opening? Is this a huge issue?

[QUOTE=KRAM36;451898]I don't see where you explained anything? Try me, I'm not afraid to learn. QUOTE] Wanting to learn is good! As B2000 pointed out we are discussing fluid flow which brings us to Navier-Stokes. Many years ago I had the pleasure of learning fluid dynamics and aerodynamics which just wouldn't be the same without the good old Navier-Stokes equations. The material isn't completely transparent, so I've included this wiki link to get you started. You'll want to brush up on tensors to get the full impact. Here's the link: Navier Now don't say I haven't tried to explain anything to you.

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Since finding the truth in lightness , I haven't been back to Porsches, so I don't come around here anymore, but I saw the I was quoted so took the opportunity to chime in. Air moves by means of a difference in pressure. That's the "voltage". It doesn't matter (mostly) if it's being driven by above atmospheric to atmospheric or atmospheric to below atmospheric. If the difference in pressure is the same, the air would act the same, again mostly. Moving air has momentum but it's motion is also subject to the pressure (force) acting on it. As air goes around a corner, the air at the inner side of the corner is accelerated more than that at the outer side. This sets up a pressure difference where the air at the outside pushes on the air at the inside which helps the airflow make a smooth turn around the bend despite the air's momentum trying to push it all straight against the outside of the wall. There is a point where the effect of the momentum overcomes the pressure difference and the air with the highest momentum (inside of the turn) pulls away from the wall and heads toward the back of the turn. This is called flow separation, you can see it in my CFD pictures. Separation effectively shrinks the size of the tube that the air is flowing through as the air is ignoring the inside of the turn and really only flowing through some % if the tube. The rest is stagnant air. The more smooth and large the inner turn, the lower the momentum at the inner wall, and the more likely the airflow at the inner wall is to stay attached. This is why the shape of the inside of a turn has so much more influence on the airflow than the outer. There is some speed threshold at any turn where the flow at the inner wall will detach. That speed depends on the geometry and roughness of the walls. The goal is to design that inner turn so that the threshold is above any speed that the engine will produce.

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[QUOTE=Jamesp;451945] The cool thing about the Navier Stokes equation is that it's really just a fluid flow adaptation of F=mA. It all comes back to Newton. Until you go down so the sub atomic level, anyway.

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[QUOTE=blue2000s;451952] Spoken like a true engineer! I moved away from hard core technical (thermal analysis on the Space Shuttle / systems design) years ago and became a manager (after my spine-ectomy), got fed up with personnel issues, budgets, long hours, and politics and so became a "systems" engineer which means I'm a jack of all trades, and master of none. Mainly work various spacecraft systems issues and project management now. Thanks for the insight on the bend radius.

That's priceless information to me blue2000s, thank you for being patient with non technical educated folks like me. Curious, if you stick your head back in here. When you did the CFD, was this done as a wide open throttle simulation? I can't make out the charts you have on the right and wondering if the air is staying attached properly to the radius of the 997 Distribution T at wide open throttle. I want to see Ben offer up a piece that is better then the 997 part. Granted he knows more about this then me, but I need to know before I toss $300 to him, that he is making the part worth that money vs $55 for the 997 piece. Right now my car is running phenomenal with the 987 air box, 996 TB and 997 Distribution T on it. I'm very hesitant to change anything in the intake, unless I know for sure it will benefit me.

Thanks everyone for the clarification on what's going on inside of that T I will try my best to give you accurate result of before and after the installation (on my car, wich is now in fairly good shape). But I don't think I will be able to dyno it :/ as I said, the main advantage of my plenum over the 997 plenum (which I recon, is a good deal), is the perfect fit "as original". Is it worth it ? I think it does ! Ben.

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The model I ran wasn't dimensionally matched to the car. I just built it to demonstrate the principles.

KRAM36 The answer to the question you asked is it has some negative effect. Is it a nail in the coffin NO! Does it add to the Disturbed air Yes. For my part my explanation of the air hitting the back of the tube is easier than trying to explain a boundary layer, molecular bonding in air molecules, or fluid shear. Any time you go back to the drawing remember this is just a snapshot. You have to understand that it's only true at the flow speed used to graph it. Now look at the white area in the center, that is the eddy(s), I tried to explain in the "Stream post" there is a light blue area surrounding it, which is another separation area of disturbed air. If you compare these 2 areas to the Y pipe below they are larger because the air runs very tightly to the solid wedge diverter in the Y design. Because it does the flow cross section is more constant in the Y design. Also because air velocity affects the stagnant air wedge in the 997 Tube the flow cross section varies more with flow speed. I agree with Blue2000 The flow would be very close in both systems with the Large radius T maybe even having a slight advantage for RPM below the point where the secondary tube damper opens. The second the secondary tube dampener opens, the IPD has the 997 tube hands down. Once the cylinder pulse has a secondary route the wedge no longer has to deal with the back flow. I get a significant power and torque boost at that point.

I'm not saying in any of this that the 997 T body mod is bad, or the IPD is the best. Each has it's place and both have compromises. Members of the forum who haven't bought one have justified their decision based in rumor or hear say and COST. I guess the $795 is high when compared to the $299 for Pedro's upgrades (some reason not available for our years any more), but why would Softronic's slam IPD. FYI they make a kit, aluminum T and tune $1975 ouch. Sometime there are ulterior motivation. I'm sure if you called Pedro to solicit an opinion he put down Softronics. I you called IPD they would down play Pedro's Kit. There each in the market to sell their product. Suncoast Porsche sells only IPD products. They state its an improvement over the stock Porsche parts but it's still $795.

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That's interesting. I don't get a sensation of extra boost through the RPM band. I get a steady very strong pull across the RPM band. Feels like I'm driving a small block V8, put the throttle down and I get a steady relentless pull to the next gear. After I got done with the intake mods and took it out for the first time, I knew it had added a lot of power.

If your plenum has any advantages and it's plug and play, then I'm in. I'm looking for simple installation with a hp gain at a reasonable price.

Awesome project My IPD intake plenum package should arrive soon, breathe baby breathe ...

NO I have not forget ! I'm just very busy and it's raining everyday in south florida (no garage...) :/ It fits ! really well ! but ... my intake tube does not ... so again, I have to wait for parts... and my paypal account is locked ... yes, i'm out of luck ^^ soooo, next time ...

It rains everyday at about 4:00! That one looks like aluminum, I thought they were going to be 3D printed.

yep, almost everyday, and when it's not raining, you're frying :/ it's heat insulation I figured that I can have a bigger radius, so the next ones will be even better

Got ya, so when's it gonna be ready for sale?

I really don't know :/ My paypal account is locked for 4 weeks (because it was created before I was 18...) so I can't buy the parts I need for the intake tube... And in the same time I'm studying for my ASE cert, my finals, and I'm going back to france the 25th :/

:'-( We want it.

Me too ... it takes way too long but I have priorities

Hi ! I receive a new elbow coupler. you should get news soon

Ok ... I know, it's been a looong time no news... I've had some problems and more important things to do over the last months :/ Now, I have a new clutch, AND a new IMS bearing, AND a new flywheel AND the intake tube fitted ! That means my car is ready to get the plenum fitted ! I will try to do it this weekend if it's not raining ! By the way, switching from a 987 to a 986 clutch sucks ...

It's IN ! And working ! https://www.facebook.com/benjamin.nenert/videos/10207860314604181/?l=7273786639763200972 The idle is slightly higher, probably due to the fact that I didn't do an ECU reset, but I should ! I drove it for 1/2h without problem, but I need a hose clamp and some heat shrink since mine is not a final version ... I did a test run, @25°c and 85% ambient humidity. 0-10 km/h: 0.99 sec 0-20 km/h: 1.90 sec 0-30 km/h: 2.53 sec 0-40 km/h: 3.16 sec 0-50 km/h: 3.74 sec 0-60 km/h: 4.35 sec 0-70 km/h: 5.02 sec 0-80 km/h: 6.59 sec 0-90 km/h: 7.47 sec 0-100 km/h: 8.35 sec 0-110 km/h: 9.28 sec Elapsed Time 60': 3.41 sec @ 39.5 km/h 330': 7.63 sec @ 87.4 km/h Miscellaneous Max Speed: 113.4 km/h Max Acceleration: 0.49 G's It's not a hard launch, I went on the throttle after 2000rpm, and I think the road goes up slightly. Sorry, it's metric I will put everything back to original tomorrow, for the week, and do another timed run on the same road to compare (I forgot to do it before). I will also try with a ECU reset to see if it improves. Ben

Please do some roll on tests from 3K in third and fourth gear What did you use for timing?

I'll try, but on open roads it's going to be quite hard to do a 3000 to 7000 in 3rd and 4th! I used Dynolicious, it has always worked quite good for me, the thing is to use it to compare, not to get an absolute result. And always get measurement on the same road going the same direction.

I just reset the ECU, we'll see how it does tomorrow. I tested the intake at up to 240F, but I measured only 150F after a drive, so it should be good from a temperature point of view

Hi ! Just did 55miles today on my daily commute, and everything worked fine ! I only did one pull WOT, and yes, it feels more powerful even on the first gear (1st gear pull are usually not showing great improvement due to flywheel inertia). The intake sound changed too ! louder at any speed when you put your foot down ! I wanted to make a video at home, but my neighbours were there trying to rent their condo, therefor I couldn't rev the engine, it would have looked bad ! I'll try with the dashcam if I don't forget it. Also, I found a better way to measure the effectiveness of the modification. Taking acceleration measurement is hard because you have to repeat the exact same procedure each time. So instead, I'll use my OBDII scanner to get MAF readings. What we want with the plenum is better airflow at WOT, and it's easy to see it with the scan tool. We'll see if there is an improvement over stock, or it's just the noise that makes me feel that. I just have to do pulls from 1000rpm to 7200rpm in any gear to compare. As long as the weather conditions are the same: Today 29°C and 55% of humidity. Ben

Would love to see some OBD MAF information with pulls and steady state driving

It's around 20g/s calculated MAF if I remember. I just did another pull on an empty back road, and yes, it definitely pulls more after 4500rpm. It red 210.5g/s. But looking at the data, max RPM says 6762, I might need to hold the throttle longer... Next week I'll take the plenum out to inspect it. I'm pretty sure it will be OK, but I have to, to collect data with the stock plenum. If someone has a S model with the 3.2L (or bigger ?) and wants to try it and tell me how it feels on a bigger engine (I have the 2.7L, and I think the difference will be bigger with the 3.2L !), and also collect some data if he can, tell me Ben

I did some pulls a while back before and after doing my UDP and found a couple things. The first was that (at least with my Bluetooth odbii reader) I was only getting updates once a second, useless for counting time to make pulls from x rpm to y rpm. I then used durametric which can read many times a second. Still not conclusive, probably due to many factors, grade of road, temp, and who knows what else still felt more powerful. I think your idea of measuring a specific metric like air flow at WOT has a better chance fir a meaningful result. Or if you were able to do multiple before and after runs on the same day, same temps, etc. There is a good thread on rennlist somewhere about doing pulls with a durametric that may be helpful and I will try. They focused on pulls in 3rd which did not get a person too high into the triple digits. Good luck and looking forward to reading more. I have got a cold air intake I picked up with a trailer I bought, while unsure of the various benefits it does come with the makings of a new intake tube that may be useful to folks doing this mod, look for it in the for sale in the next week or two.

We have a new wireless 10 000$ scan tool at school, I'll try to borrow it and do some pull with it, it has a really high frame rate. My tool is fast enough though I did another pull earlier, red 198.5g/s, but it was a first gear pull, and it was really hot outside. I'll do more Is it a cold air intake for boxster or a random one ?

Specifically for Boxster. I can take a picture tomorrow at lunch if desired and try to get a brand/model.

Good, you might be able to sell it easily Well, I have a good and two bad news ... The first bad news is I had to remove the plenum, to check it. My cel went off on my way to school this morning, nothing bad, the well known P1128 and P1130 codes. I had a vacuum leak on the AOS to plenum hose. Because the plenum is a prototype, this part is not as good as it can be (I will use another method to connect it on the next prototype). Also, I saw that it collapses at idle, nothing bad, just 2 or 3 millimeters (3/32"). The vacuum is around 8inHg at idle and it pulls everything together (just look at the whole intake system when you step on the throttle and you'll see it moving from the variation of pressure). That's why the by pass tube is ridged, prevent it from deformation that would cause the valve to bind. The stock plenum is made from a material stiffer than mine, and the boss where the two parts of the molding are bonded increases its rigidity further more. Then comes the second bad news... I have to make another prototype ! A better one. But that takes money... and, I don't have money to spend on that at the time :/ So unless someone's willing to be a guinea pig and have a prototype for the price of a printing ... I think the plenum is still safe to use, but I want to inspect it first (it's full of oil... from the AOS). Then the good news ! The bigger TB does make more power ! After installing the stock plenum back in during break at school (I had it in a bag in the car for safety !), I plugged the scan tool back, and got some readings. And it does show less flow and way less manifold pressure at WOT, which shows that the bigger TB and plenum is in fact freer flowing and have the potential for more power. My butt dyno also noticed the low end torque was back below 4000rpm with the stock plenum, but the engine chokes past 6500rpm and had less top end. I'll try to get more datas, but the IPD numbers are believable from what I've saw ! So now, back the computer to make a stiffer design ! (A wedge would stiffen it enough... just saying ^^) Ben

Hi ! Turns out the cel wasn't caused by the plenum, but the O2 sensors, as it came back today, but just the P1128. Since it's affecting only one bank and the car runs fine, I guess it's just the sensor (they are 13 years old now !). So, guess what ? plenum is going back in as soon as I can I still designed a new one, and I think you'll like it ! I'm getting used to the software: Ben

Hi ! So, nobody wants to try it on his 3.2 (or bigger) ? turns out the check engine light was in fact the O2 sensor I'm still working on the new, stiffer version, but the current one works. So If you want to give it a try, I'll send you everything (plenum, TB, intake tube and hoses for the AOS connection), as long as you're collecting some data and sending it back to me after you're done playing with it ! Ben

I could be interested, what's involved?

You might be a few hours late, I might have found someone with a 3.2 I'll still PM you with the details tomorrow... now I need sleep ! thank you ! Ben

Here is the last version, with stiffening ribbons. The Y shape plus the stiffening bits should prevent any sort of collapsing ! It is also few mm shorter, which should make things easier for the intake tube. The new AOS connections: Here you can see the larger radius between the stock and mine. I've put it back on the car this afternoon for one more test. You immediately notice the noise change. Ben

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It is installed, finally: "Not cheap, but good investment"...noticeably more "umpf" through all ranges... pulls & sounds better = more smiles per gallon

Even at low rpm ? Now that I've tried mine I totally believe IPD numbers !

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Yes. Although I have to drive a bit more (and probably getting used to the stronger pull and therefor won't be able to tell the difference more precisely), I can already say...pulls better all the way, >3500rpm even better. As my 986 is desnorkeled, the air intake sounds even a bit (not obnoxiously) louder now. Guess I have to balance that out with a valve PSE now I was skeptical at first, not anymore!

Good, thank you for the feedback !

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I'm happy to give you feedback. Doing a 3.6 swap into my 986 S. Both 2003. Let me know! Sent from my SAMSUNG-SM-G900A using Tapatalk

I'm still available if you want a 3.6 involved. Sent from my SAMSUNG-SM-G900A using Tapatalk

Hey Ben, This is great work. Very cool. What type of plastic and process are you using for 3D printing? Do you have any interest in sharing your CAD so that some of us can have them made any try it out?

Sorry PKP I didn't had time to research wether or not it would fit the 3.6 :/ Winter.K, It's stereolithography, they basically melt nylon powder with a laser, layer by layer, you have a better precision and it's much stronger than the hot ABS wire printer that you can buy for 300$. About sharing the file, the thing is, if I give you the file, I must give it to anyone, and therefor I become useless. Right now I don't have enough money to print the new version, if you want to try it, we can do something, I PM you.

Hey Ben, I totally understand. Your design, keep it safe! As for the process, I ask because I wonder about the durability of the 3D printing. I'm an engineer myself and we use Viper SLA machines for prototyping designs. They can be very high precision but the material (usually translucent) always yellows and becomes brittle within months. You can probably imagine what I'm getting at... Additive ABS might last longer if its strong enough. I'm no expert though, does your shop have other options?

Hi Ben I have been watching and I am interested. Mine is a 03S. E mail me details to try one. [email removed]

Winter.K, Ben006 is utilizing SLS (selective laser sintering) of nylon powder which results in a very durable thermoplastic part rather than SLA (most typically is a UV laser cured photopolymer liquid) which results in brittle non-thermally stable part. In my opinion, SLS nylon is an ideal material/technology for prototyping and/or short production runs of this type of part. FDM ABS would be difficult to build without support structure (extensive post build processing) and would be weak and not thermally stable in an under hood environment

SLS ! that's the right name ! That's what it is, nylon powder melted by a laser, sorry for that error and thank you for correcting Thanks gdotcvg ! Ben

Been a while since an update, hows it coming along?

Sorry, I was over in France for vacation and didn't had time to do anything :/ and I still don't have enough money ... So, I decided that it was just a waste of time for you because I won't be able to test it ... IF SOMEONE WANTS TO TEST IT SERIOUSLY, I'LL GIVE HIM A LINK SO HE CAN BUY IT AT COST PRICE. Just PM me. This is the last version, with the wedge and improved stiffness (1mm thicker + ribs) and better vacuum pick ups. The only thing is that you will need to prep it yourself, it's not hard. For now that's the best I can do, deliver a half tested product. Ben

I'm seriously impressed by your CATIA skills. That's certainly not an easy program to use, and you seem to have modeled your part flawlessly. Way to go. I'll have access to a FDM machine soon. We have a makerbot at work but just got a bigger/better machine in this week (cost only $3000 so don't expect miracles).

Thank you I like Solidworks better but only have access to Catia now. everything takes more time with Catia ! I had never heard of the markerbot, but it looks like it does quite good, but it's FDM. I don't know if it's tough enough to endure the stress, even with the new design. Ben

There is a member here who is all into engine modifications and also 3D printing. I bet he is missing these cool threads (not a (very)active member). Contact member epapp, sure he'd be willing to give it a go, dunno. Epapp got sensors/telemetry stuff also so you might get some data out of him, one day, who knows. Worth a try Cool work Ben (I'm a fan)

Ahah, thank you, I appreciate your support ! I'll try to contact them! Even if someone doesn't have anything to collect data, you can still give it a try. I think I had enough data to see how it does without the wedge to be confident that it will perform even better with it. Ben.

Hi guys! I'm done with the shifters... I can go back on this project! So... the next version is "ready", I just want to check some dimensions again, to make sure, and I will have it printed so I can test the new shape. Then if it is successful, which I have almost no doubt about, I'll make it available for everyone. I thought about having it molded (aluminium or nylon66 like the stock plenum) like Nine8six advised me, but that would mean doing a production and I don't have the time or the money to do so, that would also make the part a lot more expensive for no reason other than the fact that people might be more comfortable with something made from a material they know well :/ Tell me how you feel about it! For those still worried about the printed part melting, just remember that the original intake tube is 1mm thick ABS plastic (melting point 200°F lower than nylon), it's exposed to the same temperature, and it doesn't melt at all. The only difference is that the plenum is under a greater pressure differential, hence the webbing on the new version to stiffen it. Ben.

Mmmmh Tuesday I'll go see a foundry, I might be able to make them out of aluminum without having to do a big /expensive production! We'll see!

Is there that much of an advantage using the 83 throttle vs the 76?

I can't tell, I haven't try. But the 83mm being at least 300$, it defeats the purpose of a "cheap" upgrade :/ A 911 76mm TB only costs 50 to 60$ used! On the 2.7 the 83mm is totally overkill, and even for the 3.2 I don't think it's worth it.

So... did you guys know the IPD manifold was patented...

Yes. Pedro, FVD, Champion, and more have also made a similar product. I haven't stole their idea, neither did I reused their design. (If I did reuse a design, it is more of the original design than theirs. But what looks more like a tube than a tube ?) And since I'm aiming at a totally different kind of people, I'm not ripping them off of any of their potential customer. The IPD is a superb part, with "air bearings", a CFD designed shape, and that is 100% plug and play. For those who want to be the fastest and the best product, at any price. Mine is a simple design, only available through this forum, plastic or aluminum we don't know yet. That will require the use of a custom intake tube to fit (even if it's not really hard to do, it's not included) made for those who can't afford a 1000$ part like this, but still want to have a little fun modifying their cars. I don't think IPD has any reason to worry about me! Ben.

What you said is totally debatable and the reason why patent lawyers exist... Once you get into selling parts and affecting companies bottom lines, you open up a whole big ugly can of worms.

Well if IPD tells me to stop, of course I will! I do that mostly for fun, nothing worth getting in trouble for. That would be counterproductive! But if they haven't bother big(ger) companies, I'm not too worried. There is very little probability that they haven't seen this thread yet!

Ben, I wouldn't worry too much about comments concerning patentability or infringement as of yet. I would stay away from cast aluminum, since that is the same materials of construction used by another supplier and may be an integral part of a patent. The patent holder bears the burden of proof to show that the defendant infringed the patent. The plaintiff must prove infringement by a preponderance of the evidence. This standard means that the greater weight of the evidence must show that the patent is infringed. If you have concerns or want to take this item from a DIY project and make it a marketable product, go see an attorney familiar with this area of the law. I am not an attorney, but I am interested in your DIY project and hope to purchase one soon. Best of luck.

As I said, I do that only as a hobby and because I have enough free time right now. Nothing worth getting in trouble for! And if anything happens, I can always go back to the original straight tube shape that worked great and that has nothing to do with IPD patent. (the only reason I used a wedge on the new version is to stiffen the 3D printed part. It's not needed for the aluminum part). I went to the foundry yesterday, and I think I can do an aluminum part for a price close to the 3D printed part, the only difference is that I need, like the shifters, 10 or more person that want one to start. I'm not done with all the costs yet so I can't tell you a price. Should be around 300$. Also, I found the datasheet for the 3D printed material: https://www.shapeways.com/rrstatic/material_docs/mds-strongflex.pdf The plenum operates at a temperature way lower than those value, so it's safe. If you are interested in having one in aluminum, you can send me a PM. Thank you! Ben.

Sooo... Just to be sure, I've send a mail to IPD. We'll see!

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well, I agree that the wedge is not required - there are some flow analyses that have been posted on this forum that show that the flow naturally splits there and there is no need for the divider. the true problem is with the inside radii when the flow splits - too sharp a curve and the flow delaminates. so, the primary focus would be to make a plenum that has larger inside radii, as the OEM tube has a very sharp bend in it. the other issue is that you are limited to a smaller throttle body; 67 mm on the S models. it would be nice to be able to use a cheap 76 mm throttle body take-off from a 996/997/Cayman. you need a different plenum for that, however. the thing is, the OEM 997 plenum at $40 new meets all these needs, so the only real benefit of an aftermarket piece is to match the secondary diameters to the intake runners. That is a benefit, however, as is anything that makes it easier to install the part. with that in mind then perhaps consider the ducting between the throttle body and airbox as well, so that you can sell as a kit and add some value to your product. personally, I think the real market is with the 996/997/Cayman guys. these cars have bigger engines and can actually benefit from the 83 mm GT3 throttle body. unfortunately, there is no OEM plenum that will drop in (the GT3 intake is configured differently) and the aftermarket stuff is at IPD prices.

Thanks for the advice I just received an e-mail saying that IPD's mailbox is full, so they didn't receive my mail... we'll see Monday. My main goal was to make a plenum that easily drops in place of the old one, without complex intake tube, stretched boots and a almost factory look. I didn't like the 911 plenum solution, even is it's the cheaper and that it still gives result. For the intake tube, I don't think I will include it in a kit (unless people really want to, I can figure out a way) as it would just add complexity for me (waiting for more deliveries that might be lost... like what happened with the ball bearing for my shifters). Two of these: US 3" to 3 1 8" 76mm 80mm Silicone 90 Degree Elbow Reducer Pipe Hose Red | eBay + one of these: 3" 76mm 15deg Aluminum Turbo Intercooler Pipe Piping Tube Tubing L 610mm | eBay Will make a perfect intake tube! that's what I use: EDIT: I've just checked, I can have that cheaper if I have at least 10 people. As you said, the benefit with my plenum is the inside radius, I can't have them smoother! I first went to the Y shape because the 3D printed part wasn't stiff enough in the version I tested (but still perform perfectly!). For the 987.1, I think the use the same dimension as the 986 ? And the 987.2 is too big for me :/ Now, I will work on figuring out how to make it out of aluminum (the fittings, small details that will make it easier to produce etc...) and how to make the 3D printed part stiffer without the Y shape. In case IPD answer negatively. If you would be interested in getting one, PM me so I can see how many are interested Ben.

1) re: IPD. I don't think I would poke that skunk. Their counsel will undoubtedly ask you to cease production and alledge infringement, whether legally correct or not, just to protect their future rights. 2) while I like the idea of aluminum as a more durable material, won't it result in more transfer of heat from the engine compartment to the incoming stream of air, thus decreasing density? 3) I'm interested.

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i am interested in one for an 83 mm throttle body - i think i'd pm'd you about this quite a while back - but still need to get you the dimensions; i'll try and do that in the next few weeks.

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For peace of mind, I think I will still ask them. The T design is out of their patent, so they can't say anything about that Aluminum is stronger, but yes, nylon doesn't conduct heat like aluminum does, they both have their pros and cons: 3D Printed Nylon: -No production run needed -can easily be made to suit 76 and 83mm TB -doesn't conduct heat well -cheaper Aluminum: -Strong and durable -Better surface finish (can be media blasted to achieve the perfect finish) -A lot more expensive -conduct heat well I remember, you have a 911 engine right ? I need the inside diameter and width of the cross tube and the inside diameter of the gt3 TB's exit. Right now, I have a little something that might be interesting, I'll post another thread Ben.

I'm done with the last version. It does not infringe the patent, and should resist, it's thicker than any of the other. Pretty sure two persons (two like me at least^^) can step on it without breaking it. Problem, now it cost way more to make... but still under 300$ ! Try this link, you should be able to see it: Porsche Boxster Intake Plenum (F3SH5ZNFE) by Ben006 I'll continue to update it until I now what I'm allowed to do or not.

I should get an answer from IPD tonight! Then, last verifications and I'll make the new prototype according to what they will say ! ben.

Hi! I received the answer from IPD yesterday, and its... no. Well, good thing I already started the new version! So now, this week end I'll check the final dimension, and order the part! It should take a week to arrive. Then I'll use it for a while, I'll probably do a track day with it next month. But if I see nothing abnormal during the first weeks, I'll make it available and you'll be able to grab one! Since I need to re-check some things, I can't tell a price right now, but expect it to be around 260/270$ (without the throttle body and intake tube). Thanks guys! Ben

Here is the final version... now I just need to print it... It's stressful!

I should receive it in 10 to 12 days! For those who are still sceptic... the oil filter cover is also nylon (15% or so glass fiber), and has no problem with the oil temp and high pressure

Guess what's there! It feels even more solid than the old one! I need to clean it before trying it. It should also fit even better since the TB will be 6mm further back and will clear the starter solenoid perfectly! Ben

Nice work !!

Looks good! I continue to follow this and your shifter thread.

OKAY! This morning I woke up with a headache... but I couldn't wait more! So... Yep, I put my dirty fingers all over it! For comparison: So, first, I have some modifications to do, to make it easier to fit, nothing major, but still (it stretches the boots too much to my liking, and the PCV fittings are too close to each other.) The fact that it's 5mm shorter makes the intake tube very easy to fit, and there's lot of clearance now. I had to turn the cross tube a little because the stiffening ribs were hitting the valve mechanism... takes 30sec, but took me 15min of driving to figure! The howling noise after 5000 was missing, and the engine was very linear. I drove it for around 20minutes, the mid range torque is still present, I haven't pushed it too much, I want to go gradually. (And I don't want a ticket...) Today is a hot day with very low humidity today (35% right now) which isn't that great for power... so, doesn't matter anyway. I checked after a bit of driving: It's actually cooler than it was when it sat in the sun while I was working! So, not worried about temp problem! I'll still check after longer drives. I'll drive it as long as my AOS survives (remember last time? ^^), and check it regularly. By the end of the week I should be able to tell any gain in power (the last one did, so this one should). I did take a video... but I'll take another one where I don't film my license plate... Ben

Hi! The idle is finally stable But the AOS is starting to give up... again. It's OK, it only affect idle a bit, it's not too bad now. Like the last time, the sound is very nice! After 2000rpm it has the same power, maybe a bit more. And after 3000rpm it definitely has more power. I'll check if everything is right this evening when the sun won't cook me alive. The only thing I don't like about it... is the wind noise at part throttle, I drive without the insulation on the cover now (so I can access it quickly) and its noisy... I'll try with the insulation back on tomorrow. Again, I feel like a tune/remap would really work great with it, but I can't afford it right now. Ben.

Hello! After a week of driving it (~260 miles) the idle is now very stable, just as stock. The power as greatly increased from 2000rpm through redline, it's really noticeable! Below 2000rpm, it's different as expected. between 1300/1500 and 2000rpm, it feels like stock, and below that there's slightly less, but it's completely out of the operating range so it doesn't matter much. I checked it everyday (we had a quite hot week this week) and no problem detected. So, testing continue next week and May 24th I'll do a trackday with it. Ben

Litlle update: My gas mileage hasn't change 24.9mpg. Usually I'm between 23 and 25.5mpg. I took one of my friend for a ride, and he also noticed the increase in power, it's not only in my head testing continues! (Can't wait to be Tuesday...) Ben.

Hi guys! Another update I did a track day with the plenum yesterday... it was perfect, didn't have any problem, and made consistent power all throughout the rev range with a beautiful noise! I have to visually check it, but since the car still runs great, there shouldn't be any problem. The testing will continue until the end of June at least. My gas mileage hasn't change significantly either. For comparison: A stock 986 S https://www.facebook.com/benjamin.nenert/videos/10209542163249346/?l=3024385774512079470 Mine with the plenum, headers and mid pipes: https://www.facebook.com/benjamin.nenert/videos/10209542163369349/?l=3745880025100679306 https://www.facebook.com/benjamin.nenert/videos/10209542163289347/?l=3187950946171532859 I'm very please with it so far! Ben

So... when do we get to start buying one of these little gems?

I want to test it at least until the end of June The more I test it, the better! What will be a surprise is the dyno results I think. The power is definitely there!

Hi guys! Today I took a look a the plenum It looks good, no deformation, and still stiffer than the cross tube in fact! I do need to make some modifications because the big radius makes it a b*tch to put in... I have to try another technic to put it in easily and save the big radius! I also need to clean to outside surface better as oil can seep through the pores (Nothing major, I just need to take more time prepping it, and epoxy paint will finish the job), the first one didn't have this problem. I also found a solution for the AOS to connection, I'll show you when I get the parts. Ben

Could you make one for the 911, or will it fit? Also, why not make one that connects all 4 intake tubes? What's the point of just the connector on the rear two?

I can make one for the 911, it might happen after I'm done with the one for the boxster The secondary cross tube has a valve in it that only opens after a certain rpm to virtually vary the intake volume. Making it just one big piece would defeat the purpose of the cross tube and loose low end power.

Hi guys, Last update before I go on vacation (finally graduated )! I'm still using the plenum, and it's still giving entire satisfaction so far! It has not deformed, softened, or cracked! I found a good way to put it in and pull it out without much trouble, so I won't have to reduce the radius like I thought. The only modification that I will do is space the vacuum fittings more... nothing major. My car has giving me trouble lately, not due to the plenum, but the AOS and it's lower vent hose. I see the end Ben.

Congrats on graduating!!! I'm pretty confident you will do well in the field!

Hi guys! So... Bad news. Right now I am stuck in France for an unknown amount of time... Thanks to my school who provided excellent informations again. I've been denied access to the plane after my connecting flight in Zurich. A 1200€ plane ticket in the trash, and a trip back to Nice... yep. At least I, and everyone I know are safe! I don't know how or when I'm going to come back :/ So the plenum project in delayed... again. Ben.

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Ben. I wish you, your family and friends, all the best. Take care, and come back safe. Do not be too worry, I'm sure things will work out fine.

Some news, I'm still in France... I should be back by the end of august :/ Once I'm back, the first ones will be available! Ben.

Nice work man...come back safe! Looks like you can adapt the stock 3.2 to work with this... Can you print in black ?

Thank you Yes, it will fit the 986 2.7/3.2 (After, I plan on doing it for the 987.1 and 996). I can do it in "black". Their black is more like a dark blue. So I will print them in white and paint the outside like I did on the first one

Okay.....! I meant stock 3.2 intake tube...looks it will fit with some end treatment

Ah! Didn't understand, sorry. The 3.2 intake tube is the same as the 2.7 intake tube, they both use a 68mm TB. The intake tube I use is what I've found to be the easiest and cheapest without butchering the stock tube. There might be better solutions (AirAid UBI kit), but more expensive.

So are you still planning to sell the 3D designs online for others to buy and build their own shape?? G

You mean the 3D file ? No, I will keep it, but I can definitely make plenum for custom applications! Ben

Hi Ben. What part of Florida are you in?

PM'd you

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I thought you started to offer the design via an online 3D printing shop where you could buy the part (ie have it made) and they would ship to me, and pay you? Not doing that anymore? G

[Image-only or quote-only post; no author-written text.] https://986forum.com/forums/uploads02/IMG_02961471670888.jpg

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Sorry I didn't get it the first time. Yes, I'm still using the same service, and you will be able to purchase it through them if you want. But if you do, you will have to prep it and get the M6 nuts yourself too. And the customization they offer is limited, you can just put a writing on it, and with the reinforcing ribs, it's not going to look good. Tell me if you have any more question Alfieg, are you happy with the result in terms of power? Ben.

Hi Ben006, Yes, I am happy with the power. I also added headers and replaced my secondary cats with test pipes.

Ok, hold on. Your selling them now? Where did Alfieg get his? Been waiting a year for you, hopefully your close partner.

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Only one. When?

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No no, he used a 996 plenum! It's a common mod, but the cross tube is bigger than the holes on the 986 intake, and that creates a step in the intake. It's not a solution I like really, even though it works. When? I'll finally be back in the US Friday! I'll need to do a final check on the prototype that is still on my car, and then I'll start to make the first ones Ben

I didn't mean to create any controversy. I had purchased the parts over a year ago and only recently did the mod. I am certain Ben006's kit is first class.

..........

No problem Alfieg Alright... Who want one? But... I need guinea pigs! The one on my car is fine, it works, it has been there for more than four months now and I'm very satisfied. But now, I need a few people that are interested in getting one and that are OK to be guinea pigs: Give me their feedback, collect some datas if possible, etc Preferably if you have a S model, as I'm sure the 3.2L engine will react even better to the mod. And even better if you already have an aftermarket exhaust system! The testers would pay at cost, it's the best I can do. Keep in mind that with the plenum, you'll need to buy a 996 throttle body, and an intake tube. -You'll need to buy the TB by yourself, as I can't guarantee a used part (unless you want to buy it new... but at 360$ a piece I wouldn't). -For the intake tube, you can easily make one like mine (no metal cutting needed), it fits perfectly. If there is enough demand I can find the 90° couplers in bulk, which would cost less and include thel with the plenum. The bent tube itself is available on eBay. If you have any questions, suggestions, or if you're interested, tell me I hope you'll like it as much as you've liked the shifters! Ben

about to pm you

Im in line. Ready to experiment

I would be interested in helping I am just about to buy a 987 airbox and 996 throttle body and was planning to use a 996 plenum. Cheers David

Well, I found my testers! That was quick! I'm PM'ing/Answering you right now Thanks! Ben

Done! Here is a link for the tube I've used: 3" 76mm 15deg Aluminum Turbo Intercooler Pipe Piping Tube Tubing L 300mm | eBay + two 3" to 3 1/8" 90° bend silicon couplers EDIT: First one is ordered !! Ben

Second one on the way for testing! I've order 100 M6 nuts and bolts, that's enough for 25 plenums Ben

Cool, I look forward to experimenting. My goal is to add at least 30hp from these mods. I have access to vivid racings dyno so I'll do a couple of pulls in a few weeks. Then I'll do the install and let the ecm set for a few weeks then dyno again. Bang for the buck this is going to be a good mod.

I'm really looking forward to the dyno results! I just drove mine 2hours and had a little fun with it, it definitely pulls more than a stock boxster 2.7! Next thing for my car will be to fix the timing... too much deviation :/ then put back some catalytic converters on the mid pipes and a tune... and I'll be done for performance upgrades!

Madmodz, are you a 2.7 or 3.2? I might be able to arrange for some before/after dyno runs on my S too. I'll call the shop this week. debating just doing the dyno for the plenum/tb or adding the 987 airbox i just got too...

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, Hey Eddy, I have the 2.7 Vivid racing does a ton of Porsche work, and I was thinking of doing a flash too. I'm running 4 cats to straight pipes no mufflers. I want to delete two of the pipes and go straight. I really want to do a TPI stage 2 turbo in the future

I received the first one! It feel very good, they have gotten better with their 3d printers, there is almost no marks on it! I'm really happy with the result. Now I'm going to smooth the inside to get rid of any loose particle and paint the outside to seal it (since I won't polish the outside). Ben.

i'm no engineer, but it looks like you've designed a very nice piece.

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I agree, it looks nicely made. Someone please give me the 411 on which throttle body to use. Years, part #, what not to use. Some ebay sellers are selling boxster tb's as 996 parts. They don't mention the mm size in their listings. I even saw one pulled from a 2.5 and being sold as a 996.

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go with the 997 part. i had the 74 mm TB

987's have the larger tb too. mine came off a cayman or cayman s. i think it's the same part number as above but i will check.

I have to check but I think the one I used is part number 996.605.115.01 Can you measure the dimensions? Diameter on the outlet flange side, and bolt spacing?

there is pretty extensive thread conversation about these larger tb's being the same across quite a few platforms despite different part numbers. if i remember right, The Radium King talked about which ones were the same. anyway, the cayman tb i have bolts right up to the 996 plenum T that i have so i'm confident that it has the same dimensions.

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Thanks I just designed it, I have to give credit to the guys @ shapeways for the printing! They know their stuff! I'm done polishing the inside of the one I just received. Still have to make sure it is clean and paint it!

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I'm really excited to try it out. Thanks again for all the effort you're putting into these.

madmodz, my part number is the same as the one that Meir posted above: 997 605 115 00 and it came off a 2.7 Cayman this is a really long read but it's how i got interested in ben's product. in it, TRK and others share that 996/997.1/987 throttle bodies will all work. if you go 987, you can use either s or non s. just be mindful that if you're on ebay and you see "boxster throttle body" that the number starts with a 997 and not 986! http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter.html hope that helps! it took me a bit of time to figure out the right ones too, and you're right, there are quite a few sellers out there either misrepresenting or not knowing what they have.

And one painted:

I like

looking good!

Here is a great deal on a throttle body. Just ordered all the parts, cant wait to install it! https://www.ecstuning.com/ES2785209/

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me like this Porsche 997 GT3 RS Throttle Valve Assembly Body w Seal 82mm Bosch New | eBay maybe one day Ban will find the time to build one for my 996.

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It's cheap for a brand new one! Good find! I don't know Ban, but I'll do it I just need a 911 plenum to take measurements! The first two have been sent, and the next one will be send tomorrow! Can't wait to hear the first comment ! Ben

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Is this a 74mm throttle body??

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I think that's 83. I'm not sure if it bolts down to this version Ben made. Down the line I would like to experiment on the dyno with the 74 vs 83. I would time it a month apart after the first dyno to let the ecu adjust to the other throttle size. Well I scored a used 74mm tb for 70.00 shipped on ebay. The average lately has been about 100 bucks used. I hit him with a 60 dollar best offer and he refused it. Waited about four days and offered up 70.

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You're lucky with that price. Average price here is £120 but I've managed to pick one up for £70 all in

This is the 74mm version(99760511 5 01), whereas the 99760511 6 01 is 82mm for GT3RS.

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Nope, the 83mm doesn't bolt for now. I don't think it would be suited for the boxster' small engines. I can do one for the GT3 TB if someone wants to try it! The last one is on his way to the other side of the ocean Ben

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LOL! I can't even blame the iPad on this one.

Got mine today looks great! Sorry about the violin symbol. Have no ideal how that got on there. I got to figure out if I want a metal color or going to do red.

Getting ready for paint: painted: , Im hoping to pull 25 hp by this mod, plus doing the secondary delete pipe, and I made a custom airbox.

Pretty dang amazing

Nice Did you smooth it before painting it?

Are you still testing or are they for sale?

I'm waiting for the testers to give me their feedback on the installation, in case I need to modify something to make them easier to fit.

Hi Ben, I was out of town till today. Opened up the package and everything looks great! A very quality piece you've designed and created. I'll update with pics soon. hope to install in the next week or so.

Glad that you like it I can't wait to hear from you! Quick quick!

I have been building a custom fiberglass airbox. I really don't want to, but I must. I'm also using a evo fresh air intake. Curious if the oem tube fits around the throttle body

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baseline dyno 8am eastern monday. hope to get the airbox and plenum in and re dynoed the week after!

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A week might be too soon to let the ECM fully adjust to the plenum. try 3 weeks.

or how much driving? would like to move it along quickly

I have read on here it takes a little time to fully let the ecm adjust to the new accessories. You wouldn't get a true reading dynoing the next day.

Mine arrived today Go away for 12 days tomorrow but

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Yes, it takes at least a week. You will feel it when driving, the idle will be stable and you should feel an improvement.

I started the install today and had to re-read all 14 pages here. First mistake I made, is not realize that there is o-ring. No wor.ies, got to get some silicone or gasket maker. 2nd mistake is that I have not purchased the 3" intake tube and silicone elbows.

Size matters! Though I haven't had a chance to test due to other mods, there is no doubt I'm going to pull at the least 20hp making it the best bang for your buck item. That's 996 TB vs 986 TB .

I did my baseline dyno run today. All stock, desnorkeled. three runs, best hp was 223, best tq was 196. will get started on install later this week/early next and do a follow up dyno once the computer has had a chance to figure it out.

keep the good work guys. cant wait to see some dyno results.

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We are so curious!!

Eddy, What are you doing for a air intake?

I picked up a 987 airbox. I'll be plumbing the 986 3" MAF onto it and using 3" piping to the TB. I don't want to have to sort out a re-tune to accommodate the larger MAF.

As you guys know, Ben has a few of us beta testing the unit for fit, performance, strength etc. I would suggest changing the end of the plenum from concave to straight like the 986 oem and adding the groove for the boot to fit on. I thought my unit was not wide enough due to me having issues with the boot not providing a good seal. I measured it against the oem. The issue is the edge of the plenum. It slopes downward. My clamps right at where the unit starts sloping down. I can't get a good seal. I have the other side of the boot on the groove of the intake manifold. For me to get it to seal, I have to move the boot off the intake manifold groove and closer to the plenum. Since I have to order the silicone, a solution would be to replace the boots with two of these which would give the seal I need plus look cool

The slant was to make fitment easier, the OD of the plenum is bigger than the OEM. You should not need new boots, The clamp should fit just after the chamfer: The boots won't go as far on the side manifolds as before, but sealing is still good. The grooves are more for locating. Best way to get it easily on it to first put both boots as far in as possible on the plenum, slide the plenum in between the manifolds, then slide the boots back in their final position. Don't tighten the outer clamps before you get the new intake tube in, it won't be as flexible as the original one! Now that I've said that... You're probably right, using this method, the chamfer doesn't need to be that wide! I can probably make it narrower, that will give more surface to seal. I've put the chamfer when I was using a different method to put the plenum in: Both boots on the sides, slide the plenum in, then slide the boots over the plenum. Thank you for you're feed back, continue to share your thoughts! This is exactly what I need to know! Ben

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I'll give the GT3 TB a shot if you're up for it Ben! - J.

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I 2nd the 83mm. I know its big, but I think it has serious potential especially with a tune. One thing I must add, I siliconed the tb to the plenum before the install thinking it would be easier. Don't do that. The added weight of the tb makes it hard to maneuver the plenum when installing the boots. Both the intake and the plenum got plenty of clamping areas so I might go with the silicone boot instead of the oem.

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Thanks for this! I am probably going to install the plenum tomorrow. These instructions will help.

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If you already have them, or if they are really cheap, why not The GT3 on the 3.2L at least, I don't think the 2.7L has much more to offer :/ Well, I know what I'm going to do during the hurricane!

hey Ben, any particular liquid gasket you think will work best for tb/plenum mating? i think you sent that to me in pm but i might've gotten rid of it.

Any RTV sealant should do I've used blue one. You really don't have to put much, a 1mm thick bead will seal more than enough! Put the silicon along the small groove (it's a guideline, and prevent too much silicon from being crushed out), the bolt the TB to the plenum and clean the silicon that will have been pushed out (you can open the throttle plate by hand /!\ but unplug the TB first! /!\ )

merci beaucoup!

ok, I got started on this today. some quick notes: I removed the factory plenum using the reverse of Ben's install notes above. came right out. I observed that the AOS hole in the Ben Plenum (Benum? Blenum?) was significantly smaller than factory. The photo isn't perfect-- the inside diameter of Ben's is nearly the same as the inside diameter of stock, but then it pinches into a tiny hole. I decided to open it up a bit because I wanted to keep it as close to factory as possible. https://goo.gl/photos/Da1CYW83ZDKmMG8J8 https://goo.gl/photos/idyMc4ePW76Yb6Mt5 https://goo.gl/photos/MpXdu4YKevBP6PUq5 https://goo.gl/photos/N8Tthfft5pYTWAkw8 After sanding it smooth and cleaning it up I test fit it. A little side to side adjusting and it lined up well. I'm confident that the bands are tightened down on enough plastic and nothing is going anywhere. https://goo.gl/photos/WEZxo1DtjyHpPiBCA Going to pull it out because I have to do the 987 airbox and it might be good to have it out of the way. Also going to do the AOS while I am in here. Will make a little progress in the next two days but it'll be next week before it all comes together. sorry about the links; having trouble posting pics.

Eddy, I would be interested in hearing your impressions on the 987 airbox install. I have done a lot of reading and understand how to mount the MAF, however am curious about what it takes to get the 987 airbox in and connected. Thanks and good luck. Gary

Sure thing, Gary. I will probably do a separate thread about the whole install in addition to offering feedback in this one about the plenum itself.

This is a great development by Ben with everyone's input suggestions. More heads on a design can be better than one and the results will likely prove that out. I am trying to get up to speed on this and figure out how to get the most out of this on my 01 S. Also be great to summarize where we are with this design and testing results/impressions. Q1) What is the primary objective of this part? From what I have read the goal is to improve the aerodynamic flow of air into the engine, over the stock part, which should result in a greater Volume of air available for combustion, smoother airflow, quicker throttle response etc. Q2) Has anyone calculated the current volume of air over an rpm range of the stock part as a baseline and compared it to the New design? I think you could probably use the MAF readings on a Durametric to easily read those values. Retaking those MAF/rpm readings with the new plenum will immediately tell whether an improvement has occurred with the new design. This would be super easy to accomplish. You should also be able to calculate air velocities to determine what you would need to do to make the greatest improvements. The Y shape should be better than a T if the diameters/volumes are consistent. Any change will increase or decrease airflow speed which will result in less than optimum results. Q3) With the new improved air volume numbers one could calculate the amount of fuel required to make use of the extra air available and perhaps using the O2 sensors readings determine if the existing mappings are able to supply enough fuel to use all the available airflow. Again more calculations or observations of the sensors? Once this is determined then you might get an idea whether an ECM remapping would be beneficial. Q4) What are the current diameters of the plenum. What TB's will fit? From reading Im seeing 76mm 997 TB and 83mm GT3 TB with 73mm being stock size for the 2.7L engine? Q5) If you are fitting a bigger TB like 83mm wouldn't you want to increase diameters upstream including the airbox. Can GT3 parts for the upstream components be used or would it be custom? What comes in must also be able to exit even faster so opening up the exhaust flow might also be part of the optimum tune. In the case of cars with 4 cats removing the secondary cat has opened up the exhaust flow rate to help in that regard and the car can still pass emissions. It would be nice to list the combinations tried so far and what the results were so we all don't have to go through the learning curve, and can get optimum results right away based on the amount of work we are willing to do, ie Just the Plenum vs Plenum & TB vs Plenum, TB and exhaust etc. Perhaps you can edit Thread #1 to include all the latest info and results. Kudo's on undertaking and documenting a cool sort-of open source development of a 986 part. Looking forward to seeing the results posted.

Very nice eddy! I made the hole smaller as to disturb the airflow in the plenum less. The AOS is what controls the airflow through that it, and the size of the hole is large enough to vent the crankcase To fit the airbox you will have to remove the left side manifold so yes, you're going to remove it JB: -Q1: Yes the main goal is to decrease the charge loss, resulting in greater airflow and thus greater power. I haven't really noticed a change in response though. -Q2: Yes Few pages back I talk about it. I did a few test runs, and I've measured an average of 8% more airflow. Unfortunately, I could only compare maximum value, so I don't know exactly at what RPM it happened (probably near maximum power rpm). I can't do a Y shape, it's patented, and I don't do that to get troubles Q3: The stock ECU is able to make it run, no worries on that. But a remap would get the most out of it. Q4: The stock TB for 2.7 and 3.2 engine is 68mm. The 911/987 TB is 74mm, and the GT3 is 83mm. For now, I only make it for the 911 TB, because I believe it is the more suited for the application, and also cheaper and easier to find. I will make one the BIG 83mm TB later, and also one for the 996 cars to fit the GT3 TB. Q5: I talk about it a few pages back too. The plenum and TB should NOT be your only mod/first mod! That is why I've ask the tester to have at least an exhaust. My configuration right now is soft, I run eBay headers and midpipes, and the plenum... I'm going to fit a k&n filter soon. a 987 airbox will be a good addition, that's why eddy and mavis.d are doing it I can't guarantee that the car will pass emissions unfortunately! I'll try to do a summary of everything on the first post I might have found an easier solution for the AOS to plenum connection, might even be cheaper than the current one! Thanks guys for everything! Continue to give your opinions! Ben.

As I was boring out the hole I thought that you probably made it the size you did for a reason When I make my thread for this whole install I will note that you sized it that way on purpose and what I did isn't necessary. I would expect that this isn't going to change emissions at all, although I understand that you can't guarantee that! JB-- good questions, all. I look forward to sharing my dyno numbers for this + 987 airbox as a reference point for intake mods here.

In thinking about/visualizing the airflow, I had a thought and some more questions and ideas. What is the orientation of the TB? does the throttle plate pivot about the vertical axis (like a door) or Horizontal like oven. I'm 99% sure the plate must be oriented so that it pivots about the horizontal axis since the other option would be a serious problem for even distribution of airflow to the left and right intakes. With the scenario of a partially closed throttle plate I am thinking that the airflow would benefit from an small induced spin to reduce the impact of stagnant air pockets that are not moving and would disrupt the smooth flow of air and cause turbulence. That means that the flow divider should also have a complementary twist to neatly divide the flow without blocking the imparted spin. You could design some small short fins that stick out behind the TB to impart a gentle mild spin. Of course that sort of minute detail might be hard to test because many iterations will be needed to determine the optimum fin angle/length and resulting improvements in performance. But sometimes those kinds of innovations cause break-through's that along with a patent is what makes inventors stupidly rich. We need a flow modeling App to try this out and speed the development.

Without CFD or 10 different iteration each dyno tested, there is no way to make a real improvement. The plenum has the shape of the stock one, with larger radiuses on the T. That is the only part that is 100% proven beneficial.

This has the potential to be a very cost-effective upgrade. Ben's put a lot of time in and I'm excited to see what the gains are as-is, and if he wants to incrementally improve from there I am all for it. This is a great example of someone in the community filling a void!

I wonder how much impact this mod (plenum + 74mm TB) has using stock 986 airbox vs the 987 airbox?

Got the 987 box in. A little under 2 hours to get the 986 airbox out, probably 3 to get the 987 in-- fitting, then cutting, then re-fitting, then wishing that Porsche made bigger engine access panels, etc. Cliff's notes: trim as much as you can off the 987 box because it's a super tight fit. I had to loosen the left manifold. Lowering the engine saved a lot of aggravation. --- figuring out how to mate the 986 MAF to the 987 box. Thinking that I am going to use a silicone pipe reducer where the 987 MAF clips to the box. Apart from the vacuum line i broke, that should be the last part i need to get this done.

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This is a good question because clearly the 987 air box is a huge pain and will deter some potential customers.

The problem with airboxes... is that, basically, the bigger the better! But also the more pain it is to fit... I'm going to test a K&N panel filter tomorrow, and see if that makes a difference in the stock 986 airbox. I believe the 987 airbox is a good mod to go along with the plenum, but not 100% necessary, I don't have one (but I have the headers and mid pipes). I might give the 987 airbox a try if I'm not satisfied with the K&N. And maybe design something to make the modification of the box and the fitting easier! I will contact a Porsche tuner soon that distribute GIAC tunes and have a dyno, see if we can work something out ! It won't be cheap though... We'll see, I'll keep you in touch! Ben.

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I agree. I thought about doing some testing with the 986 but ultimately decided that I wanted to just jump to the 987 box. I thought about other intakes but liked the fact that the 987 box is not open to the engine bay. I'm sure it can be done more cleanly, but I had to bend the edge of the access area. I also elected to not cut the part of the body that buts up to where the box makes its turn, meaning that fitment isn't perfect. Just a bunch of little headaches that I'm fine with but wouldn't encourage others to dive into. Progress update: box is in, plenum is in. Decided to get a silicone reducer to facilitate the MAF setup, so I've gotta wait till that comes in and then plumb the route to the TB.

Eddy!! We need pictures!! I put the K&N in today too. Just like the plenum, the first minutes felt weird, less sound, less power, but a very smooth power delivery. When I got home (I installed it during lunch break...), it felt nicer, but still quieter than before! We'll see how it does in a few days! I took the time to inspect the plenum quickly, looks good after 6 months or so ? (I don't remember when I put it on ?). I found a place where I can put a bit of reinforcement too. Don't worry testers, yours are totally fine! But if I can make it a bit better, I will Ben

pics coming soon i promise!

So back from holiday and time to crack on with the upgrade. My plenum arrived the day went away which was a bit frustrating. I'm just waiting for the pipe and 90 degree bends to connect it all up. As my car is used 3/4 days a week I have decided not to swap to the 987 air box due to time constraints. Planning to do the work on Thursday (day off) Looking forward to reporting back with some pics

If you don't use the 987 airbox, you should try the K&N drop in filter! I'm very impressed at the difference it made!

So, guys! Today we met with ChrisZenithBlue for an autocross event, and since we have both 2.7L base models, we did a bit of comparison. And I can confirm that my setup makes a difference! especially down low, the car just goes, and the power delivery is smoother! I do run thicker oil than he does (15w50 vs 0w40)! Now I really want to see the dyno results to put a figure on this difference! And by the way, I would have never thought that a boxster would make such a good drift car ^^

finally got the silicone reducer i ordered. with luck, the car will be up and going sometime tonight.

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Haaa haaa, that explains all the knocked over cones? !

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go go go I actually haven't knocked a single cone

Heres some pics of my setup. I'm using a design-tek FAI. Its also sold as a agency intake and I'm sure other names. I drove the car without an intake around the block and it drove good. I then did a plug change and tried to drive it today. The car will not idle past 2000 and I pulled these codes. Only difference is a plug change, fai mounted. Got to research these codes. Anybody have any ideals?

Maybe you accidentally knocked off some electrical connections? If not ,note the codes, clear them and see if they return as Pending Codes after a few drives?

check your aftermarket intake - if wedged in there, it might be pressing on the wiring to an injector (#6 - closest to the back on the driver side) and causing an intermittent electrical connection.

If it happened after the plug change, recheck everything you did. I hope it's not much! I see that you used the piece of hose that I provided! how did it fit? Did the coil prevented it from collapsing? How did you get it straight on the AOS ?

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I'm too burned out to work on her tonight. The aos hose was a little tight, but it fit with no issues. I did use the 15 degree 3" pipe that I cut down quite a bit. I also cut the elbow coming from the tb to give less of an angle. It turns to sharply in.

got mine in. cut the aos pipe just a touch because i couldnt get it unkinked. went for a drive and everything seems to be working great! it was wet out so i really couldn't push it. sounds great, though! i started a write up but it's time for bed. really excited that it came together! i'll be driving it for the next several days to let the ECU learn it.

If the AOS hose is too long you can always cut it, but I was more afraid of the other way round, because if it's too short... it's just too short ^^ The 3" pipes needs to be trimmed a bit to make it easier to fit, along with the elbow, like you did. I mentioned it I think? I need to make a better first post like I just did for the shifters... but now, It's dinner time!

Wow Ben. I put 200 miles on the car today. Pulls much harder across the rpm range. I'm thrilled with the results. The quality of the piece is clear to see when you look at it, but the proof is in the pudding, and I have to say the pudding is pretty good. I am headed back to the dyno (hopefully next week, waiting for a time from the shop) to verify the gains. Once that's done I will post about the install. Cliff's notes: 987 box is a pain (we knew that) Ben's Plenum is easy peasy; I also came up with a decent way to attach both using existing silicone piping and a bit of aluminum pipe. Stay tuned!

This P0306 code has hampered my ability to drive my car. It ran fine before. I pulled off a coil from another boxster and it did th e same thing. Flashing p0306. So what I have done: 1 coolant flush 2 oil change 3 pulled off intake/fuel rail/injectors and painted 4 plug change 5 tb and plenum change. Would the fuel injector have anything to do with this code? I haven't really driven the car, just around the block a few times. It has no power.

the code came after the plug change right ? Make sure you have a spark on cylinder number 6. If you removed the injectors, did you change the seals? One thing you can do is swap the plug/coil or injector (one at a time) from cylinder 6 to another and see if the code moves to that cylinder, once it moves, you've found what is causing the trouble

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Yes, put new seals on the injectors, but had no ideal if they are balanced. After I put back on the intake manifold, it wouldn't rev right. I was thinking I had a fowl plug. This was before I added your plenum, so I know that's not the issue. Tonight Im pulling the whole sides coils off and pushing them back in. To check for spark, I put the plug in the coil and ground it while trying to start the car right?

I believe the coils ground through the bolt, so you have to have them in place :/ keep us in touch!

I have a dyno session set for tuesday am. i'll share results then!

Cool! Can't wait to know! I think all three of you have put it in? It's soon time to make them available! If you're interested, you can already send me a PM! Once I'm done with the shifters, the plenums are next! Ben

Hi guys I'm a bit behind on this due to holiday and work commitments. Also the 2 hoses I ordered came wrong so hope to get on with soon

After switching coils, I'm still pulling the P0306 code. Car wouldn't rev pass 2000. I unplugged the MAF and it revved fine. So next thing is I'm going to pull the MAF off another boxster and try it out. So heads up, if you pull one of these codes, unplug the MAF to see if it clears up the problem.

Weird that it only misfire on one cylinder though. You might have a dirty cyl 6 injector too.

The injectors have a little disc filter in them.That may be plugged ? The injectors are pigs to remove with the engine in the car. Really need the special tool.

All right everyone, sorry for the delay. I put 350 or so miles on the car after the 987 airbox and ben plenum/big tb install. It feels significantly stronger and the sound is better/louder than the desnorkeled 986 box i had before. I felt from the midrange up it really woke up the engine. From a "feel" perspective, this has been a wonderful upgrade. Unfortunately I only got 3hp and 3tq according to the dyno (223 hp up to 226, 196tq up to 199). Temps were within a few degrees of one another, humidity was similar. I was quite surprised about the results. In order to better understand if my car is an anomaly it'd be great to see the results from a couple other cars. The dyno guy (Hutter performance-- typically a GM tuner, but they had, of all things, a 962 there for a tune when I was there. They're a really well-respected shop in Northeast Ohio) said there was room for more power if I got a tune, but he didn't think there was a lot there to be gained. So the numbers don't appear to be there, on my car, anyway, but if I hadn't gotten it dynoed I would've thought this was a solid 15 hp+ upgrade. Wish I could have reported a more positive result, and I hope I am an anomaly! I'm still very happy to have done this, though.

Eddy, Thanks for posting the results. Did you get a graph showing output through the rev range? I would think with the mod there is more area under the curve, ie there is more power throughout the rev range vs being 'peaky'. I think max values are interesting, however more so is how much more power you are getting across all engine speeds. This is likely why you are feeling more of a positive difference than reflected in the max hp and tq values.

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From what we have seen, your results are about average, with most of the small gains at the high end of the RPM curve.

I've been driving for little over a year with this mod and equally surprised at such low numbers. My experience with this mod is a bit of low end sacrifice with great mid/top. I've got to give it more gas out of the hole mostly due to the bigger TB but once past 4k it really wakes up. Acceleration is greatly improved once past that 4K area and quickly reaches redline. On another note, before I swapped to the larger TB I ran just the stock 987 airbox and that alone made a big difference with the old setup. Just wanted to pass that on in case one would under go that route. So, I'm thinking a lot of the gains were probably mostly due to the 987 air supply.

I have found this mod to be wonderful! I did what is mostly this mod about 300 miles ago - I installed a 997 TB and plenum while keeping the stock 986 air box. I have a 986S with 2nd cat deletes, Crios mod muffler, and UDP. Also have a fresh MAF and spark plugs. Just updating the throttle body and plenum has yielded fantastic gains for me - although subjective (no dyno) it is clear the car has increased power throughout the rev range and is much more responsive. My car always had great power above 5k rpm however was a little flat under 4k, as if it was waiting for a turbo to spool up. I wanted more uniform power delivery. With new TB and plenum it feels like I have a new engine - really opens it up from lower RPM's and loses much of the 'choked down' feeling. Character of engine feels more like a 911. I am sure that Ben's plenum will bring great results as his design has smoother curves - and be easier to install. This is an easy, cheap mod that is highly impactful and one that I recommend.

Thanks for the feedbacks on your experiences guys, even though you're using a different solution I also was really surprised with the results as I felt the same as you! A flatter power curve, a small loss below 2000rpm, but a solid gain between 2000 and 4000, and still better breathing after. You can see here: https://www.youtube.com/watch?v=i6wD-U7kONc that I'm always in second gear, between 3 and 4500rpm, and the car doesn't lack power despite having 117 000miles! No problem initiating a drift either! I want to start selling them, but I really believe that you NEED supporting mods to get results. Mavis, Madmodz, any update on yours ? Ben

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That is what counts, your satisfaction! I bought the complete IPD package and it is noticeably louder and pulls stronger...and gas mileage went up a little. They (IPD) show an average of +15hp@wheels on their dyno charts. And I am happy, too. ...no matter if it is a +5 +10 or +15hp gain...it just feels better. That is what counts.

So after a long wait I finally got the plenum and 74mm t/body installed. Did it after work last night and finished tonight, it took about 3hrs in all. In the end I went for a K&N filter rather than the 987 air box due to time constraints, also looking how much space there isn't it looks a pig of a job! Hard to get many thoughts on the way home as it was wet and dark so giving it full beans on country road didn't seem to sensible. I have a trip over the Yorkshire moors to Whitby this week so we'll see how it goes.

It looks really good in black and without oil stains like mine ^^ Wow, how did you get the 3/4" silicon hose to fit over the 1" AOS tube? It wasn't intended to be like that, but if it fits that's cool! It doesn't collapse at idle with the EZ-coil right? Give it some time before getting results Ben

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I did. I've been at an event all weekend and will share the graphs soon. it is a slight gain not just in peak but from the middle on up.

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what should i have done with it?

Deleted due to sideways photo. see below for photo of dyno graph

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You were supposed to cut the accordion hose and reuse the quick disconnect on the AOS, but there is not problem to do like you did Did it take a lot of effort to get it like that?? Thanks Eddy for sharing!

here you go

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Ahh It took a bit of time but then I put in some very hot water and it went on OK I did it that way because I don't like butchering standard kit in case I have to go back to square one in which case you're kippered unless you have a spare.

You can sacrifice that accordion hose without worrying, it will break if you look at it too much! I'll try what you did on one of my spare AOS to see how it goes, it might make things easier for me!

Still can't get my car to drive right. Just got my maf in the mail. I was thinking of going to the stock plenum and tb to see if I can get this car running right. Just put a 2nd new plug in it and switched injector 5 over to injector 6. Still pulling P0306. Hopefully the maf is the issue. Eddy, did you use the 997 airbox on both runs? That airbox alone should be at least 5-10 hp. Was a fan pointed to your air inlet during dyno.

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First session was stock desnorkeled. second was 987 airbox + ben plenum + 74mm tb. I did not have a fan blowing into the air inlet on either run. Good that I did the same thing twice for control, probably not ultimately best for numbers. I'm going to start thinking about tunes and exhaust and hopefully these will start adding up. Yesterday was probably the last 70 degree day (it snowed today) in Northeast Ohio, so naturally I had the Boxster out. I swear these numbers are low, but I can't figure any reason why they'd be off.

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The MAF would cause all cylinder to go bad. What have you done so far to correct it? By the way, I've tried to put the silicon hose like you did Mavis, and it went pretty well, so this is the final solution! The plenums are officially available! I realized that mine has been on for around 6000 miles, on trackday and two autocross events already!

So 3 weeks after finishing fitting it’s time for my update. Fitting Total time to fit took around 3hrs. Personally I found the ends of the Plenum a bit too rounded and felt this made it fiddly to fit. Less rounded and more of a chamfer may work better, that’s my just my opinion, other than that the plenum is really well made and Ben had gone to the trouble of painting it matt black which looked good. I didn’t have the time to fit a 987 air box so have gone for a K&N filter for the time being. Driving Seat of the pants says that there is a good improvement. Starts at 3 and builds over 4 becoming much stronger that before. I have the speed warning set to Back to the Future speed and find it coming on much more often, which is nice! I had planned to do a session at the rolling road next week but can’t make it now so will try get there before Christmas and find what the figures say. Great work Ben keep up the good work Cheers David

Thanks for the feedback! I'm glad you like it too! What do you mean by rounded? The curve radius between the two tubes is too big and interfere with the boot? If yes, it's unfortunately one of the compromises I made for better airflow. The wheather started to get cooler down here ("cooler" but still South Florida) and my car is responding to it very positively! Way more than the other years, which makes me think that a remap could bring the car to another level! So, guys, as I said, they're available! A good Christmas gift to offer to your Boxster I have to finish the update on the first page too... I whish we could change the thread's title. PM me for any questions Ben

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Hi Ben No I meant the end of the T where it meets the inlet manifold. I found that it slipped of quite easily and took some time to get fitted correctly with no air leaks. Could it be a bit longer or would that make it too difficult to fit? It could be just me though!

I see! Making it longer would make it a nighmare to fit :/ I changed the rake of the chamfer for the next ones, there will be more sealing surface

Hi guys! I'm proud to say that the first plenum has been sold! (Well, the first that is not for testing) I'll post pictures of it Ben.

Mavis said:" I didn’t have the time to fit a 987 air box so have gone for a K&N filter for the time being." Don't get the idea that removing the airbox and refitting the larger(better) 987 airbox is easy. The stock airbox is difficult to remove because of the confined space. In theory you need to drop the engine a few inches, unbolt and move the Bank 2 inlet manifold. Even tht may not give sufficient clearance to remove it. That is why you'll fin Threads of despair describing how to cut up and break up the stock 986 airbox to remove it. And you think that fitting the larger 987 airbox will be easier? for example : " On 8/27/2016 at 0:26 PM, marseille said: it's not that hard to fit the 987 Airbox you just to remove all the unnecessary plastic from the airbox then the left hand side manifold, fuel rail remove the rear wheel to help with access in pulling the airbox down low enough to fit into the engine bay 10 minute job then😜 And more here: http://986forum.com/forums/performance-technical-chat/32074-987-v-986-air-box-8.html We really need Ben to design an easy to fit one!

The only reason why I still have the stock air box is because I HATE messing with this intake manifold on M96s and M97s! especially driver side. :/ Sounds like Porsche's instructions ^^ "Removing engine: Disconnect plugs, drain coolant, remove bolts, remove engine" I don't think I can really improve on the aftermarket air boxes available. Cheaper: yes, better: hardly.

The geeks may find this related thread interesting even though it relates to an inferior application of the M96 IDP Plenum question - Rennlist Discussion Forums

well, if we are referencing rennlist ... here is a similar thread but with some interesting comments by mr raby himself: Alternative to IPD Plenum - Rennlist Discussion Forums

So what he says is that what I did was the right thing to do: Increasing the inside radius!

So just to clarify, all I'd need to purchase is a 997 75mm throttle body, fit this onto the manifold and the throttle body, and fit the existing intake tube onto the other end of the throttle body? Sorry, seemed to be a couple of things that have changed on this page and the previous page in terms of tubing!

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You will need a Throttle Body and larger intake tube and bends from the MAF to the T/Body. I still have to tidy up the pipework but if you look at my running report in Boxa.net there's a couple of pics. If I'm not too delicate after Christmas tipple on Tuesday I might sort it out then http://www.boxa.net/forum/index.php?/topic/61193-mavisd-running-report/

You can't reuse the stock intake tube since it's made for a 68mm TB, the 74mm won't fit inside! Making an intake tube is just a matter of assembling an aluminum tube and two silicon coupleurs Mavis, we can't see the page :/

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As you can see from the second pic the angle needs to tidied up. The aluminum tube is 76mm and each of the silicon couplings are 76-83mm

Mavis - it would be really great if you could specify the adapter coupling - do you mean a 90 degree elbow reducer 76/83mm ? Or a different angle? Like this?? eBay item number: 282061203413 Imagine how much easier your project would be if the airbox was not in the engine bay? Yes , a CAI outside the engine bay - it can be done ! But I don't want to hijack Ben's Thread.

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It's a 90 degree elbow but I think a 45 might work better so may give it a go with one of those. BTW your ebay number brings up no items

If you use a 15 degree 3" tube, you need a slightly less than 90 degree coupler for the TB. A 90degree coupler cut slightly shorter works fine. I'll post pictures tonight! Gelbster, you mean an air filter where the snorkle is usually ?

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Try EBay USA ! It works just fine.

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Oh, what's that??? Looks like a GT3 TB

cant wait to get in on this action as soon as i finish with maintenance expenses! nothing like a more linear powerband with more usable low end grunt. coming from the honda S2000 i can say i miss the vtec kick at 5500RPM which was pretty damn cool but the reality is you dont get much of that daily driving. when i met Ben a while back and drove his boxster i could REALLY feel the difference in the powerband and it felt so right, like it was supposed to be like that from factory. i personally like the max power output of the base boxster, it doesnt get you in guaranteed "jail time" speed right away, the only thing i would change is how that power is delivered. good thing there's guys like Ben making this stuff happen!

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Yes Ben , I cobbled together an experimental air filter from "UNI" foam and fitted it in the 'tunnel' where the snorkel usually is.It fits behind and is attached to the louvers.One screw and it all slides out. The use of the tunnel as an air filter housing enables a very compact new arrangement in the engine bay where the old airbox was. Access to the Bank 2 - 4,5,6 inlet manifold area is now excellent from above. The concept needs proving. And improving. I am (wildly)guessing that I have an acceptable compromise of filtration vs. obstruction. I also fitted a finer mesh screen(like the997 has) .I also fitted an airflow straightener before the MAF. Who knows if ..... The project was not planed.I had to r&r # 4 injector and the fuel pressure regulator. Try that with the engine and airbox in place and you'll understand. I am not advocating this as an effective project because I do not have test data.

I'm selling a 997 throttle body, 997 plenum and misc. hardware. It's listed in the Boxster Parts for Sale section.

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I'll take a look at the possibilities when I have the time The first sold plenum is ready ! You'll notice the four ribs added. Just for security and further stiffening! You'll also notice that my masking tape game is not the best one yet... ^^ I ordered a 996 plenum too. I have a GT3 throttle body at home and a guinea pig who's willing to test it on his 996 Ben

how much is this plenum?

Aluminum conducts heat very well and turns all your hard work into a hot air intake, probably negating any possible benefits from the plenum. You'd be much better off with a plastic tube with heat shielding.

This Plenum is plastic ! Agreed for conductive heat ,but the heat source in this case is radiated and convective,not much conducted because of the' rubber' boots. Which is why polished aluminum or 'chrome' coated ABS are usually used for commercial CAI systems. Spectre products has more info. Heat reflective tape may help ? The air charge in the CAI tube moves fast enough that it won't have time to absorb much excessive heat. Hot-Idling/Dyno would be a problem because of heat soak. But some Track time would be more valuable than my theorizing.

The DEI gold reflective tape works great. I used it on the engine bay side of a custom airbox in my SCCA ITS Miata (the box was made from sheetmetal) along with some thin silver duct insulation on the filter side. temps were near ambient as a result.

Agreed but use ALuminum/chrome on a Porsche - gold is soooo Ricer !

It does have greater reflective properties than silver, plus with the race car it was on i wasn't headed to the local cars n coffee our two thread conversations are a welcome distraction from the spreadsheet i should be working on!

I don't think you'll feel a difference with reflective tape on the boxster, but for the price... you might try! I put some on the first version of the plenum. I feel that the 986 is really sensitive to outside air temp, I can feel a difference between morning power and noon power, even though it's only 10/15°F difference. I think it has more to do with the ECU settings that advance timing when it gets hot than the actual difference in air density... I got a new phone so I'll be able to do datalogging easily now. I'll try to collect the right info, see what's really going on!

Soooo this week end I had a ton of things to do... so I decided to do something else! I received the 996 plenum, so I made my version for the GT3 Throttle body, fairly easy since it's a straight T! Due to its symmetrical shape, I made radial stiffening ribs (like the OEM cross over pipe)... And I really liked it! So I tried on the 986 plenum... due to the non-symmetrical shape... it took me all afternoon... But how cool is that! I really like it! It's also probably a lot stiffer... but also more expensive and a ******************** to paint... Ben

This is some nice work Ben. How is this comparable to the stock unit airflow-wise? Bigger means better in this case? Still waiting for the 2.5 power kit, i.e. the car that needs it most imo lolll

Thanks Smoother bends than the original plenum, and bigger throttle body, and yes, bigger is better on this area! The only compromise is noise. A bigger throttle body is noisier (air noises). But really, you don't notice it. The problem with the 2.5 is: where to find a bigger throttle body? A 993 TB? Or an aftermarket one? The plenum has the same shape as the 996 plenum, straight T, so it'll be pretty easy to make. Thought, it is bigger than an "e-gas car" plenum, so it would be more expensive! If someone want's to be a guinea pig, I'll be happy to work with him!

Or get one of these OBX Individual Throttle Body ITB Fits Watercooled Porsche 911 Boxster | eBay :dance::dance::dance: And just to be clear. I'm first in line for the 996 plenum.

For a mechanical body 2.5 the upgrade path is the mechanical body 996 3.4.

Well I was ready to go back to oem configuration because my car didn't run right. Couldn't clear a misfire to cylinder 6 code after changing everything. My screwup. I switched the fuel injector wire with one of vacumm plugins so they look the same. Best news I had all year! So tomorrow I will rebuild her.

Ahah, that happens ^^ Glad you found the problem and that it's nothing bad

First 996 plenum installed!

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is apparently a private post, I can't see it I see a box with "This Facebook post is no longer available. It may have been removed or the privacy settings of the post may have changed."

crap... there it is:

Can anyone tell me if there is an aftermarket or oem throttle body and plenum combo that works with the stock intake tube on a 3.2? The technotorque 2 is discontinued and everything else (Ben's, ipd) requires a new intake tube. It doesn't look like you can buy ipd's tube separately either.

If you want a bigger throttle body you HAVE to use another intake tube. The intake tube has the same diameter as the throttle body. You can make an intake tube for pretty cheap, it shouldn't be a problem

Just to recap (sorry), I'd buy from Ebay: - 74mm Throttle Body - Larger intake piping I'd buy from you: - 74mm plenum So the larger intake tube would fit on to the new throttle body, which would fit onto your new plenum. Anything else I'd need?

No that's all! You already have the exhaust, I just recommend a K&N drop-in panel filter, it's cheap and worked wonder on mine!

Sooo, I have been quiet lately... not because I gave up... But because I've been very busy I'll let you guess what it is And I spend the rest of my free time doing this... full makeover for my 986S! I also started a website and an enterprise that will be in working order very soon ! Ben

Eheheh

WTF!!! :dance: Hit us with the details Ben006!

For now, we’re running into problems with the inner part of the mould. It should be resolved soon with a better suited mould

Good looking stuff there Ben , but if you want a REAL challenge how about designing and producing an AOS that performs and lives in the real world ?

As you said, it’s a real challenge, and unless I quit my job, I won’t have enough free time to work on it. I already designed the plenum back when I had plenty of free time I keep that in a corner of my head Ben

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You can install the motorsport aos if you want a solution.

True ! But if I remember that’s quite an expensive upgrade !

I fitted a 74mm throttle body and plenum from a 996 for not a lot of money to my 2001 Boxster S. I purchased a silicone elbow/reducer off eBay, a piece of aluminum tubing, and another silicone coupler to connect to the stock intake which was trimmed. all for under $100. Tuned ECU for larger TB.

jd, Good job! I'm inspired to replicate your project

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Very true, but if someone wants a solution, its there :-)

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And ? Noticeable results? How'd you tune the ecm? DIY? Or Take it to somebody? Sent from my SM-G930T using Tapatalk

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Yes, it's a well known mod. But it's looks a bit too "hacked" for my liking. Ben

More coming soon

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Wow! Looks amazing.

I received it today. It's just the prototype, so there are a few things that will need to be looked at. But man it looks and feels good ! That thing will handle anything you throw at it !

So... almost done !

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What kind of tune ?

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That is beautiful! Is this the final product?

Hey Guys, I'm new to the Boxster world but have owned several other Porsche's from the air-cooled era. Not to worry, I sold them out before they became ridiculously valuable so I could retain my original buy high, sell low strategy. My 2001 S is crazy clean, like near showroom (probably never spent a night outdoors in its 42,000 miles traveled), but I would like to capture it's full potential if possible. I drove it straight to the professionals upon purchase to have the IMS bearing replaced for peace-of-mind for starters. My question is, can I change the headers, cats & mid-pipes, plenum, throttle valve and air box without sending the ECU into protest via check-engine light? My plan is to retain the stock outward appearance and not compromise practicality. If it's possible, I'll commit, if not I'll continue to live with the strangled 250HP.

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Please pardon the self-serving promotion: http://986forum.com/forums/boxster-cayman-parts-sale-wanted/73195-sale-hollowed-oem-exhaust-manifolds-complete-mini-cats.html

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The carbon fiber part yes, the plastic flange no, it'll be slimmer and better looking Yes you can do all that without a tune and without getting a CEL. Install cheaters for the secondary O2 sensors if you're going cat-less, that's all! Ben

I've done a little research on the mods I posted about earlier. It looks like all of them are a long slide for a short gain; headers & exhaust for $4000-ish for 6HP, intake mods for $1000-ish for 6 more HP and a tune for $800 for about 6HP more than that. 18HP is a lot but $6000 is a lot more than that. Can anyone share their experience with these upgrades? What's the seat-of-the-pant dyno results? Should I just leave it alone? There has to be something- or a combination of things - that softened the potential of the 3.2 S, the specific output is considerably lower that other models of the same era.

You might take a look at my YouTube channel: https://www.youtube.com/user/12shoes2 I have covered all these mods in my videos and the result was quite noticable once I had everything in place and a tune done. I wanted to get a dyno done but unfortunately I threw a rod bolt on my last track day this fall and now I need a new engine. This engine failure had nothing to do with the mods that I made but stuff happens at the track.

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That's a crazy high estimate for those particular mods. Divide it by four-ish, perhaps even more if you buy used as I had suggested to you earlier here. To illustrate further, here's another idea for your consideration: http://986forum.com/forums/boxster-cayman-parts-sale-wanted/73389-sale-fabspeed-200-cell-986-header-%96-new-never-used.html By the way - Out of respect for Ben's thread, you would be better served to start a new thread on your topic, rather than to continue to be off-topic here. You will likely gain a lot more traction and interest.

I can't speak for the exhaust/header gains as it seems like a small HP gains for the $$ invested (not cheap) but for little wrenching and small investment of couple hundred bucks you can do the 987 airbox, 996 TB, and 997 T as a single mod and I think you would be quite surprised. Power gains throughout the rpm range and wider smiles at least for me. Butt Dyno says to me about 10 -15 just my opinion. It's a different car and no Cels. Passes smog no problem. Bang for buck 👍 Hardest part is 987 airbox

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Ben, is this for sale yet?

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Is it for 82MM GT3 TB? Can it for into 996?

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I'd suggest read the thread. all is revealed within..... ::spreading arms in an expansive way::

Not for sale yet, I'm still waiting on that intake tube ! It's been more than a month now...

I finally received the temporary intake tube ! I will be fitting the plenum on Saturday OOOH I'm excited

So... You know me by now ? Nope, it's not fitted yet ! Though, the tubes are fitted ! Very happy with the result ! Dare I say it will be fitted this weekend ? hummm...

OK ! Late again, but it's IN !!!! I replaced the K&N filter too... I haven't driven it yet, just parked the car... I know I'll have to wait a bit for the DME to adap to it, but I already know this is going to be awesome ! Fitment is perfect, everything goes in without trouble, the intake tube fits (very close, but it fits without touching !) I've taken pictures of the install so I can have step by step instructions to include. It's a prototype, so some things might change for the final version but it's mostly there Ben

Quick update ! I've hit 600km with the new plenum and throttle body. The DME has now fully adapted to the new parts, and I have to say that I love it ! First, the sound... I still have the stock muffler, and there is more intake noise than exhaust noise ! I have a RHD Boxster, so I'm driving on the wrong side... the airbox sitting in the passenger side, previously I was not hearing much intake noise... Now ? I love it ! The sound is louder with a higher pitch, without being annoying ! It sounds way better throughout the rev range. In terms of performance, it took a while to adapt (no tuning done for now) but now it's a blast, with a very noticeable improvement from 2000rpm and up ! The torque dip between 3 and 4000 rpm feels better than before, the engine is pulling very strongly from down low all the way to the redline ! If I should make one complaint, is that it's a bit more linear now if you floor it from down low. I'll try to get it tuned soon to see how much can be extracted from it, but for now, it's already a very fast 986 ! I might make one modification to the plenum, to keep the stock AOS tube. What do you guys think ? Keep the sotck AOS tube with quick fittings, or replace it with a longer lasting, cheaper to replace but not as clean looking silicone hose ? I like the silicone hose for it strength, but it doesn't look as clean as the stock installation with the plastic hose and Y fitting. Ben.

I have to start by saying great work! But you already know that. I personally prefer the look of the stock connections and corrugated tubing. For me, the hose clamps detract from the look. I guess it ultimately depends on the complexity and cost of making it connect to the stock fittings. After all, who really sees this part of the car anyway. By the way, I assume the design does not incoporate a “splitter” to separate the air flow to both intakes. First, would you even recommend doing something like that. And second, if so, how would you recommend attaching a splitter? Ready in March I hope?

I suggest making it most likely to pass the visual Inspection for Smog Test.Yes, I know it is unlikely the average Smog Tech would know what to look for but if you ever had to go to a Referee it may be an issue. "I might make one modification to the plenum, to keep the stock AOS tube. What do you guys think ? Keep the sotck AOS tube with quick fittings, or replace it with a longer lasting, cheaper to replace but not as clean looking silicone hose ? I like the silicone hose for it strength, but it doesn't look as clean as the stock installation with the plastic hose and Y fitting."

What do you guys think ? Keep the sotck AOS tube with quick fittings, or replace it with a longer lasting, cheaper to replace but not as clean looking silicone hose ? Keep the stock AOS I see there is no price on your website Ben, any idea how much and when?

I’ll try the silicone hose with spring clamps instead of hose clamps, that way it will look cleaner. The first batch will be with silicone hose until I test the other solution They should be available early March, for around 450€ with the complete intake tube ! It’ll be almost a drop-in kit ! Ben.

Dyno Results

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Look forward to that, currently working on exhaust and now broke so timing may be good.

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Two more : Smog Test. If this mod or some boy-racer stickers get you sent to the Referee ....... Let's try to fly under the Smog radar? Helping the AOS and SAI issues would be a great bonus.

No dyno results... Two reasons : -It's quite hard to find a dyno around here -I don't have enough time to conduct such a test... it already took me weeks to find the time to fit it on my Boxster ! Though, I bet you won't need a dyno to feel a difference. It's big enough to be felt by anyone, even without a tune. I understand that for some, this is not enough... so I bought a complete 986 intake system, and I'll do a comparison of the pressure drop across it with the stock plenum/TB, and the carbon plenum + big TB. We'll see if I can show significant results this way or if I just bought some expensive wall decoration ahah. Ben

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Looks great, but could you clarify if you used the 83mm or 74mm throttle body in the final application. I read back and I know you started out with 74mm. Thanks.

Two reasons : The 83mm TB is huge, and is hard to fit underneath the 986 cover. And requires more than just the plenum to fit, which would make the kit more expensive. With the stock airbox, it becomes a limiting factor way before the 74mm TB, so unless one fits a 987 airbox, it's not justified to pay extra for nothing more. Soooo, I'm a bit late on schedule ... But they are finally DONE ! Yes ! The glue is curing, one last sanding inside, and DONE, just have to pack them and ship ! I'll contact all of you that have contacted me for one. I'll take care of selling the first batch, so if you want one -> PM If you want to hear how it sounds : It's mostly intake noise, stock muffler ! Ben

Here is the complete kit : 8 left Ben

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To clarify does this kit use the original TB (74mm)? How much for the kit in dollars ($) shipped?

It does use the 74mm throttle body, which is not the original 986 TB (68mm). Price with shipping to the US in USD is $540. Price is based on 450€ base price, and change rate change everyday (and paypal has its own rates...) so $540 is an indication. Ben.

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Holy Mother of God! I was chastised over this post and 1 1/2 years later the great Jake Raby says the same thing I did about the air being pulled along the short side radius. The Y shape is the most important part of the piece, even according to Jake Raby. https://rennlist.com/forums/996-forum/944002-alternative-to-ipd-plenum-2.html#post13767949

Is there a similar solution for the 2.5 engine?

Nope, not from me yet :/ I should do a before/after dyno comparison soon ! Well... when my car comes back from the lift and passes inspection ... Ben

so 4 years on and it still isn't available to buy or have any dyno results etc? crazy

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It's only crazy if you think this is what he does full time, for a living. It's not. He spends the time (and money) here and there when he can. Which isn't a lot, since he's also a full time student. His work is absolutely first rate, and he's been very helpful to the community. Sent from my SM-G970U using Tapatalk

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Instead of denigrating the efforts of Ben, why not offer some suggestions of how to improve his product or development process ? We need more talented, motivated and generous members like Ben to support the Boxster. with after market products. Snarky comments are unlikely to encourage such helpful members. Big companies are not going to create such products for such a small, declining market so THANK YOU BEN ! Yes, I was one of his first customers and the product works perfectly and was great value. So I am a grateful, biased user .

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THIS. a hundred times this. I've got Ben's shifter, and I'm looking forward to his improvement to it becoming available. I'll likely be lined-up when the plenum is available as well. Sent from my SM-G970U using Tapatalk

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What they said. Ben’s customer service alone has me sold on his products

Thanks guys for the support I don't think he was serious, but I think I made pretty good progress in 4 years ! The plenums are available (and carbon fiber!), there's two coming in the US with Uniwerks Design ! I'm not a student anymore, I moved back home and I'm a full time Porsche tech, and doing my stuff the rest of the time There are three plenums left, two that will arrive at Uniwerks Design soon, and one here with me. Ten more are coming. I'll try a new thing for the AOS tube soon. I found a guy to dyno the car... now the hard part is to find the time ! Talking of plenum, I recently made one for my 928 ! It's just a prototype for now, but looking pretty good already ! Thanks again to all of you Ben

Hi Ben, a little idea for improvement. The both ends of the T that lead to the hoses should have a little hump, so that the hoses can't get of the tube. Another question: how is the T formed inside? Is there an air guidance? Where are you located in France? I saw your video driving on Auneau Du Rin. If you live near there maybe i can help with searching a dyno near the border in Germany. Regards, Markus

The previous 3D printed ones had the small humps you describe, but after trying with and without, it doesn't do much. They were good to help the porous 3D printed parts with sealing, but on the CF part, there is no problem at all The inside of the plenum is a regular T shape, with larger radiuses to improve flow. I didn't use a Y shape for various reason. I live in the south, on the Riviera Which video was it ? Because I never went (unfortunately for me ^^) on Anneau du Rhin. I go back on track in two days ! Hopefully the gopro stays in place more than 5 minutes this time ! ^^

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ah ok i did not know about his background. I clicked on his website, and given that he has a company name and a proper website, the natural conclusion was that this was a company doing this. apologies for any offence, Ben.

"i can help with searching a dyno near the border in Germany." Well done Markus ! That is the best of this Forum - helping each other :-).

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No worries I do have a company, but I still work 8am to 6pm as a Porsche tech, so I can only work at making my stuff around an hour per day... that's not enough to do everything I want unfortunately :/ And add to that three project cars and time to socialize and take care of my girlfriend ^^ It's a fulfilled life ahah Today I finally got the chance to take the Boxster on the track ! This time I came prepared and had no oil problem, so I enjoyed four 20minutes sessions of fast driving ! Keeping the engine below 6000rpm, I still kept up with way faster cars : 981S, 718, 718GTS, E46 M3 ! A wonderful day !

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Which track did you go to, Ben? Sent from my SM-G970U using Tapatalk

A small track in the south of France. "Le Luc" I'll post a video

Hi guys ! The first two plenum have finally landed in the US ! Available here : https://uniwerksdesign.com/product/porsche-986-carbon-fiber-intake-plenum/ There're ten more coming by early July. I have to do an oil change on the Boxster and I'm off to the dyno, I contacted the guys and we agreed on how to do it. I'll do two passes (after driving for half an hour, so everything is already up to temp), swap the plenums on the dyno, then do two other passes. That's the most accurate way of doing it without spending a full day on the dyno... In the future I'll get it tuned too, we might see a good increase in HP there too ! Ben.

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Very nice Ben. and fairly priced if i might add. keep the good work.

Add me to the list of individuals eager to see the dyno results for using this intake kit both without and with a tune.

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My interest is growing; rightly priced! Let's see the dyno

I'm waiting on the new oil... I decided to switch to a thicker 10w50 oil, but haven't received it yet. I can not wait to finally know how much gain there is ! I've been running the 74mm on the 2.7 and the 3.2 for a few years now, I know it performs well, but putting an actual number on it will be awesome !

I should receive the oil tomorrow ! The car is already on the lift and empty Getting its new coilovers too !

Hi all, let me start by saying that I really admire this work, love it! I am in the middle of my Winter-projects, got a 987 airbox incoming, 987 MAF on order, 996-TB. I´m torn between the 997 plenum and Bens beautiful creation.. If I where to keep the standard airbox/MAF I would not hesitate, but with the 987-airbox the MAF will end up just behind the oil cooler. Anyone knows how this would line up with the angle of the Ben-plenum? I realise that the kit won't work, maybe there should be another kit for us who wants to go further and add the 987-box? Any thoughts? :dance:

Hi ! Thank you for your comment The kit will work with the 987 airbox and MAF housing, I have at least two customer doing the same thing, one on a 986 2.7 and the other on a 550 edition (which has a 987 airbox from the factory). You will just need to find the correct intake tube to connect the two. If I remember, a long 45° silicone elbow works. By the way, the new version is out, and it features a quick disconnect to reuse the factory AOS hose, making the installation simpler and getting rid of the silicone hose I was using previously And the 996 Version will be there in 2020 ! Ben

Thanks for the answer Ben, good to know it will work with the 987-airbox. I do Believe your plenum is better then the 997-plenum (that I have considered) since it enables a smoother overall bend. I sent you a pm btw!

Hey Ben what's the possibility of making intake manifolds that are sized like the 996 but with the bolt pattern of a 986 ? The increased size of intake plenum and throttle body would be enhanced by the larger runners of the 996 . And by making the mounting foot print the same as existing 986 eliminates the drilling of the heads . Just a thought to expand your catalog of parts

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I had the exact same thought, just two thoughts on this topic: 1) On the 996 intake there are aluminium "runners" 99611010152 between the plastic part and the engine, I honestly don´t understand why, however, a custom intake would then need to cover also the alu part to get the 986 bolt pattern. Actually, to adress the bolt pattern issue only the 99611010152-part with custom bolt pattern would need to be made. 2) I think that the "real" issue with the 996 intake is that it does´t fit in the bay without lowering the engine quite a lot.. So if this could be adressed while maintaining the flow characteristics of the 996 part you would have a winner! Quite a big/complex part to manufacture i guess..

You would have to port-match the heads too... pretty expensive job. To me, it's not worth it. Though if you really want to I'm able to make the spacers to fit the 996 intake on to the 986 heads. With a 987 engine cover it should fit. But then, without camshafts and a proper tune I don't think it's worth it :/

Ben, I believe the 996 intake runner port size and the 986 are the same. They are the same head to the best of my knowledge. At a high level, you would need to: laser scan the 996 aluminium intake runner left and right bank parts; develop the 3D model; adjust the height if possible (not sure this would be easy to adjust without negatively impacting geometry); map the 986 head holes onto the bottom flange of the model; incorporate fastener feature up top as needed; 3D print in suitable material. I am not sure about fuel rail and injector fitment Please make this. I have been wanting adapters for years!

If they are the same heads, then no need for an adapter ^^ The 3.4 engine fits in the 986 so we know there is room too ! No need for a laser scanner, it’s a human that designed it, humans like round number and geometrical disposition It’s not hard to design, but won’t be cheap and won’t give big power gain if any. I still think the intake manifolds on the 986 aren’t restrictions. The small throttle body and tiny airbox are major restrictions, the rest is large enough for the stock cams/valves and displacement. And the closer you are to the valve the more you can mess the accoustic tuning of the intake and risk losing driveability :/

Any updates on inventory of the 986 part?

I have one left in stock ! But there is also one coming to the US for Uniwerks design. Due to the situation, I don't think he received it yet !

Though this thread is few months old, it seems the best spot for my question. I've fitted the 997 'T" and 74mm TB. For clearance reasons, can I mount the TB with the actuator block on top rather than the side? There is enough cable to rotate 90 degrees but will it work fine in that configuration? I don't see any obvious reason it would care, but one of you might have contrary information. Thanks!

It will rub on the engine cover :/ There’s a reason why I bother making it like that

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tell me about the 996 version? Will it work on a 986 w/74TB?

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Amazing job specially that it's looking so great. Then what's actual gain in HP with the install ? Tuned and without tuning ? Sent from my ONEPLUS A5000 using Tapatalk

Hard to tell until I dyno one. Hopefully this summer I'll have a guinea pig to dyno one

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Yes, u can mount the TB in any position you want so long as the connector reaches to accommodate fitment. I have mine (82mm on modified 996 cable driven plenum) mounted with the actuator on the driver's side. I'm not sure if Ben was replying to your post but it makes contact with the engine cover but it has not caused me any problems after driving like that for several hundred miles. I don't think you will have this issue though since the 74 is smaller. You can see the pic in my diy thread. Sent from my POCOPHONE F1 using Tapatalk

With my plenum the throttle body stays in the normal position and doesn't rub anywhere. With 911 plenum it's another story

I did a bit of reverse engineering on my own part now that I have a scanner ! here is the superposition of a stock 986 plenum, and my carbon fiber one ! As you can see, the transition is more straight between the two tubes and it has nicer bends. For that I had to move the throttle body to the left and forward a bit to clear the starter solenoid ! What took months before would take only hours now !

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I'm not sure how that would fixing the rubbing? My 996 plenum is a straight T and the issue is space between the starter housing and the engine cover, not the angle of the plenum. Also, if you've changed the angle/location of the TB, is there enough play in the stock piping to make up for this? My stock intake is long gone but from what I remember there's very little if any play in those accordion sections. Sent from my POCOPHONE F1 using Tapatalk

Well, mine doesn't rub because the throttle is where is was stock. No above the starter solenoid wich makes it too high. you can not reuse the stock intake tube if you go to a bigger throttle body.

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Now that some time has passed. Any luck with some dyno runs? Curious to see the numbers. Definitely interested if theres some good gains and they come back in stock. Sent from my iPhone using Tapatalk

Not really unfortunately, I've been too busy building the company for the last 6 months :/ I have a customer that picked up around 30Hp with the plenum, exhaust, and a tune on his 2.7L 986. Right now I'm testing the 996 version. it still needs a bit of work... I had a youtuber that was supposed to come (piston Kirk) but due to COVID he couldn't make it. We'll see in the winter if he can come and we'll do a back to back dyno with the plenum installed and removed. Ben

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The shop I work at has a dyno if you’re going to get these back in stock soon and want some solid data Sent from my iPhone using Tapatalk

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And I'm a customer of that shop if you need a car to test it on! They already have the "before" dyno data on my car!

Hi Ben Have you made something for the 987 3,2?

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Thanks guys ! I'm waiting on a few tools to make a V1.2, easier to fit and a bit better looking I'm not sure of how the 3.2 987 inake is ! Is it the same as the 3.4 m97 or the same as the 3.2 m96 ? if it's like the 3.4, I was to supposed to scan a car to finish the part... but the owner couldn't make it. So I'm waiting on another occasion !

Just thought I would post a link to the dyno on Ben’s website. There is also a YouTube video by Piston Kirk that reviews it. I’m on the fence about whether it’s worth it. https://benautodesign.fr/en/home/20-plenum-admission-carbone-986.html

That link only takes one to the catalog page. No dyno there.

If you scroll through the photos, it’s the last one on the right.

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OOOOH it's been a while since I've last been here :O Here is the dyno graf : https://benautodesign.fr/261-large_default/plenum-admission-carbone-986.jpg No other mod, not even an air filter, worst scenario for the plenum. Still managed a noticeable gain !

Curiosity got the better of me and I ordered one! I already have your shifter and side lever. Do you have any other 986 products available or in development? Is there an air filter you recommend or have experience with?

You ordered it from Uniwerks Design ? For the air filter, if you are willing to clean it every 6months, a K&N does make a difference once you have the plenum ! If you don't want to bother with maintenance, the paper filter will do. Fitting a 987 airbox is such a pain, both in term of physically fitting it and electronically making it work ! Though it's the best option for a 986... Right now I'm stalled on the new and improved throttle pedal, as I had other products to finance first. Once the others products are up and selling, and the new website is working, I'll get back to it I do have rear toe links for 986 too. Adjustable to be able to retain good alignment on lowered cars. And I'm also working on an affordable lap timer / g meter solution Not 986 specific, but an affordable way of tracking lap times or rally stages time without hassle, USB-C power, setup a few coordinates and go ! As I still work alone (and got back to work for Porsche) everything takes soooo much time to develop... Add to that my 3 broken cars

Ben, curious about 987 airboxes. I know the difficulty installing them even engine-out, but there are no electrical connections so what do mean when you say they are hard to integrate electronically?

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If I had to guess I would say he is referring to the fact that there is more airflow, especially if you do the larger throttle body, that the computer can't compensate. At least that was my experience. When warm and at idle I was showing around 17-18:1 AFR, which is VERY lean. I used an APEXi SAFC to modify the AFR and so far it's working very well. I should be going to the dyno either this week or next to see where I landed on power, and to possibly fine tune it. @Ben006 you mentioned a throttle pedal, I was just about to order the assembly from Rennline, are you working on something similar? If so, any rough timeline? I'm not in a rush, but I'm willing to test anything for you! I already have your shifter and side bushing and LOVE it!

By electronically, I thought he meant the tuning or flashing required to use the larger 987 MAF, or the finagling required to keep the 986 MAF. But I didn’t think about the fuel trims… 🤔

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As redpepperracing said, you have to correct the AFR. The 987 airbox uses a 3.5“ MAF housing. The 986 a 3“. The MAF sensor is the same, but in the bigger housing it measures considerably less air mass (as the velocity drops with the increased diameter). When driving around, it’s usually OK as the the DME is running in closed loop, constantly adjusting the fuel trims to keep the afr in the right place. Though, when going WOT, the DME is running in open loop, and relying on it’s long term fuel trim and adaptations to adjust fuel. There is a chance of running quite lean. The bigger throttle body has kind of a similar effect but the MAF is still reading correctly, so the adaptations and fuel trims are accurate I always recommend driving around for a week after installing. You’ll know when the adaptations are done as you’ll take your car one day and feel the bump in power. The first few days the car will actually loose power as the DME detects a change in the throttle position / MAF relation and pulls timing to avoid failure. For the throttle pedal, as much as I would love to bring it to the market quickly… the last prototype I test myself wasn’t up to my liking (even though my guinea-pig loves it), and I made several changes to improve the movement of the pedal. Rennline product is available and tested. I can’t compete for now :/ hopefully mid 2027 https://imgur.com/gallery/FVnLhJY#K3VckPV https://imgur.com/gallery/FVnLhJY#qsWt8UB It does look awesome in my opinion, and it articulates on a carbon fiber spring ! But I haven’t found the perfect position yet. I do have a second version being tested in a 986 that races in the UK (samrs1400 on instagram if you guys want to check his page). I have to fetch his feedback on it ! He wins races so it must be good 😂

Follow up question. I’m stuck with 91 octane out here. Will my engine be able to utilize the increased air flow? My understanding is that engine has to pull timing slight to compensate for the lower octane.

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Those imgur links don't work. I'll have to decide how badly I want to replace my pedal! I took it apart and added a couple of screws to hold the clips in place, it feels way more solid now, but I haven't actually driven it yet. It can probably wait for now. Thanks! Tom

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Yep, the DME does protect the engine that way through knock detection. Though, improved airflow always mean more power potential. So you start with less power, and end up with less than if you were using high octane fuel, but there should still be a gain ! Are you in California ? The part is not CARB legal, I don't know how badly that can affect you ? Your order is received though and I'll pack it tonight after work

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Arh, was on my phone so I couldn't get the proper links...

Very nice! I wish it was available, I'd buy it right now!

Just a thought, I have an OMP pedal cover, so it seems like a combination of your lower pivot hinge and the carbon plate plus the OMP cover would be most of the way to a set. Can you sell just those pieces?

Can you show me ? The part that block right now is the extended link in the back. I'll work on it and get a proto soon as I have already plenty of stuff to have made !

This is what I have now. Adding just your lower block, and some kind of attachment to the cable mechanism should be all I need.

Getting back to the original thread topic, I dyno tested my car yesterday. To recap my setup I have the following: Intake side: - 987 airbox - 987 BMC filter - 987 intake tube and MAF - 45 degree elbow - 997 throttle body (74mm I think?) - 987 modified distribution tube - 996 plenum and runners Exhaust side: - 996 equal length headers - 2 inch stainless tubes - 2 inch high flow cats - 2 inch valved mufflers Other mods: - AC delete - Electric PS conversion - Underdrive pulley For tuning I am using an ApexI SAFC. AT WOT, my AFR is around 11:1 (logged with an AEM wideband), so I need to adjust that, but it's better to be rich than lean. Here is the chart, blue is mufflers fully open, red is mufflers fully closed. I should have done a 'partial open run', but I didn't. I'm pretty happy with the results, I'm basically at crank power, to the wheels. Without doing a lot more very invasive mods, aside from tuning the AFR, I don't think there is much more I can get out of this thing.

http://986forum.com/forums/boxster-general-discussions/25000-how-do-you-upload-pictures.html

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Not sure who you are angry with. I added the image link to my post originally, I just edited it and re-added it and I can see it. It's possibly related to the SSL certificate expiry.