987 v 986 Air box - Page 9 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Major difference in size between them, bigger is 987. There is some modification to the muffler area of the 987 box for clearance, otherwise it bolts right up.

We trimmed it back a little farther. Can you show us how you made the cover for the opening?

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I just covered the hole with a piece of plastic and glued it on. Had visions of making a smaller muffler with the cut off part, but decided against it. I want it to make noise. With as much as I have going into this car and engine, I plan on keeping it for a long time. Not concerned about resale at this point.

We glued and bolted an aluminum plate over the hole Used the typical 10/32 cap head screw and some nylocks.

I appreciate the information, and photos. But, I have to ask.... and what? Bigger doesn't mean better. Have you run flow tests on the two? Is there some expected result you were hoping for, and achieved? Thanks in advance.

I started with common sense Hum.. I have a 3.4L CaymanS engine in a 986 Boxster, I wonder if I should run a CaymanS intake box? (question I asked myself) We had a custom cone filter setup in the engine compartment, but they do not seal well to the engine lid or the chassis, and we would see intake air temps 40-50 degrees hotter after just 30minutes of running the car than we did in a stock CaymanS Cold air makes power (or at least closer to ambient) I had been involved with CaymanS 3.8 conversions and knew the stock box seemed to work just fine with the larger GT3 throttle body on a 3.8 The stock box is too small for the 3.2..... about right for the 2.5 and 2.7 (same piston size in both engines) When we see vaccuum at full throttle on the dyno, it means something in the intake system is too small and if the intake and the engine is stock..... it means the air box (to me) B

Thanks Brad. It could be common sense, with some of the follow up information not previously seen. Did that vacuum go away?

It's tough online to see me smiling when I post "tongue in cheek" comments Thanks for not getting offended. It was meant in jest. Yes, it went away and the engine air inlet temp went WAY down. Down to what we expected to see based on a stock CaymanS. GM has a division dedicated to inlet air temp on the Corvettes. After meeting a person who works in that group, and what I have seen on professionally raced Boxster's and Cayman's... I take air inlet very serious (to the point of covering the entire intake/air box/piping in the gold foil to keep the temps down. Heat kills!!! Porsche cut the nuts off the Boxster's and Caymans. The trend for larger throttle bodies and larger headers is well founded, but you have to match it with a larger air box. So far the CaymanS airbox has proven to be *good* up to 420hp. I have not tested past that (GrandAm M97 engine in a CaymanS)

I keep looking at the air box on my racing car and wondering if there is not a better way to get cold air with higher volume into the engine. I was considering putting a plate on the location of the factory air box and running a tube out closer to the side of the car for the air filter - or how about relocating the air box/filer to the rear boot. That would give a straight line from the filter to the throttle body/plenum. Then the air filter could be feed with air via a scoop on the rear trunk or even the roof? Just an amateur thinking-out-loud, so sorry if this is all just stupid talking

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Brad, Do you have any experience with running an intake duct sealed to the outside intake "scoop" running to the throttle body....insulated of course. I have seen a fellow on here who did a marvelous job. I would think intake temps would be reasonable. The air would be spending less time running around the engine compartment...like a heat exchanger. I would certainly like to put in a Cayman S box (MY year?) but I am still not seeing how one can possibly get it in. I am not understanding the muffler cut either. The Cayman box plus the IPD might give me enough juice to get by some older 911s on the track

questions for Brad. 1. can the swap to a cayman airbox be done with the engine in the car? 2. where are you sourcing the cayman airbox? Model year and what price? thanks

In addition to my questions above, I was wondering if the MAF housing was the same diameter as the 986? if not, do you use the 987 MAF sensor in the 986?

Reading the replies now.. didn't receive a notification that someone had posted

Tommy, you want to use the CaymanS MAF housing. It holds the same MAF your 2000 car runs. I happened to have one close to my desk. I'll show you the CaymanS MAF holder and boot, then show you the 986 (side by side) B

As far as pricing goes, I expect to pay about half of new when buying these parts from places like LAPD/OK Foreign/PartsHeaven Part number: 987.110.021.00 NEW Price from Porsche is $560.00 You will find it in cars from 2005-2008 ALL 2.7/3.2/3.4 cars.. all of them.. B

Stock 2.5/2.7/3.2 utilize a 74mm diameter inlet at the MAF sensor. CaymanS utilizes a 82mm opening!!!! Just noticed the spider in the BoxsterS MAF tube.. LOL

Tidbit of info: The 987 tube has a MUCH finer screen to help protect the MAF compared to the early 986 style (The 987's rarely kill a MAF like a 986 does)

JayKay, I have not seen exactly what you are explaining, but I do understand the concept and yes, anything you can do to seal the aftermarket "cone filter" setups to the outside of the car.. is GOOD!! Muffler: Porsche has installed a resonator chamber/muffler to decrease (or control) the sound of the intake on the Boxster's/Caymans. They accomplished this by a "pimple" hanging off the intake tube, on the 2005-08 cars this "pimple" was part of the air box right where it makes its transition to the throttle body. I'll show you with a picture..

thanks for the great pics and info. So I can just re-use the MAF from my 986S but put it in the 987 housing. Its not calibrated to the tube diameter? Can the housing swap be done with the engine in the car?

"can the housing swap be done in the car" Yes, but you will be removing the drivers side intake plenum "So I can just re-use the MAF from my 986S but put it in the 987 housing" Yes. Correct. "Its not calibrated to the tube diameter" The MAF is not. The computer will adapt

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If you use a larger MAF housing diameter without reprogramming or otherwise changing the signal, the DME won't be calculating air volume correctly. The car will run leaner than the DME thinks it is.

I do tune the cars that I have used this setup in, but I also believe that the stock ECU (no flash or tune) can easily adapt for this and headers. This really is only slightly different from installing a cone filter setup. Thoughts?

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I have doubts. The DME uses the MAF to measure air speed. It needs to convert that speed to volume flow so it knows how much air the engine is injesting. The conversion calculation has to include the diameter of the MAF housing. Increase the MAF housing without telling the DME and it thinks the airflow is lower than it really is. Same speed + larger area = more flow. And not a little difference, it's a 23% increase in area! Huge! I would be really surprised if there was some way the DME can compensate to that change. It means Porsche would have had to allow for housing changes while programming and then figure out a way to double check the sensor. I don't see a system that can make the correction. You know how slow O2 sensors are, they aren't fast enough to make a meaningful correction. They are mostly used for steady state (cruising) corrections. And there is no MAP sensor to verify flow with a pressure measurement. I bet when you do a tune, the car is running very lean to start, yes?

Thinking about this

They are not lean to start, but I know why they are not lean.

Funny part? I run the cable cars with the MAF disconnected pretty regularly. The base map in the ecu is pretty damn good.. Still thinking. Everything you posted makes perfect sense. I understand what we are doing (I'm not using this on anything smaller than a 3.2) but I will in the future.

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The base map with the MAF disconnected probably runs fuel metering off the throttle position sensor. So it's probably fine as long as you don't mess with the cylinder filling efficiency of the engine (very free flowing exhaust and intake) and you don't change the size of the throttle body. If you do those, it'll probably go lean again. But the non-MAF map is probably conservative to begin with so it might bring the fuel level to about right.

Correct. TPS metering. The throttle response is not as crisp when I have them disconnected. I have seen multiple cars adapt upwards of 20hp with no computer change, knowing that we changed the plenum (after MAF changes) Typing out loud

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With safe AFR's?

I'll install one of these on a stock 3.2 engine with headers with a before and after A/F readings. I have a gutted stripped 3.2 race car in the shop that will be easy to install one on. I'm pulling the engine this week anyway! B

i've been looking into tuning recently and here is what i think i know: dme looks at (a) maf signal (amount of air going into the engine) and (b) rpm, to determine how much fuel to deliver via the injectors. this is done using a 3D, 3-axis map (x=rpm, y=quantity of air, z=amount of fuel required). these are the maps that get modified by tuners to increase performance. dme then looks at exhaust o2 sensors to see how things went during combustion. depending on the amount of oxygen in the exhaust, the dme either adds or removed fuel by lengthening or shortening the injector pulse. this information is put into a short term fuel trim map (stft) as a % modifier of the primary map. if the stft stays stable (ie, over about 50 kms of driving) the data is transferred to the long term fuel trim map (ltft). this is your dme 'learning'. if you find that your ltft is staying at a constant value (ie, +5% due to intake modifications) tuners can go to the maf calibration map and calibrate it so that your ltft zeros out. you may wish to do this to make room for other modifications, as max ltft is 25%. so, if you put a 3.5" diameter maf housing on a car that needs a 3" housing, you are looking at a maf that is reading 36% out (pie are square, right?). dme can't adapt to such a significant change. worse, your engine will be getting more air than it thinks it is and run lean - hard on engines (no cooling). you can do it, but a dme remap is required. however, it also shows that those who state their intake products require an expensive remap (which they also sell) to realise full benefit are wrong, unless airflow is increased by more than 25% (not likely).

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That should be interesting. Hopefully it's interesting, anyway.

Porsche runs these super lean anyway, but yes, more than safe.

King, you pretty much nailed it. nearly verbatim to what Porsche has released in factory bulletins!

I'm all up for learning Now, sharing what we have learned? Not always

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That's never a problem for me, I always know all the answers

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Brad, do you think I'm safe to run the stock tune with the 987 box and stock throttle body? I plan to upgrade the TB and plenum at a later date, and probably headers, then tune it to match.

Let me get it installed in a stock Boxster-S with headers. I'll use a stock CaymanS throttle body on the 3.2 plenum and report back with numbers.

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It all makes sense. But I wonder if the DME just makes small corrections to one load/speed point on the map at a time or if it tries to smooth the map around the point of correction. The O2 sensor isn't fast enough to relay good data while the engine is dynamically changing, like changing loads or RPM. It needs the engine to be steady for a while to know what the conditions are at the intake relative to the exhaust. Although, I suppose if they charactorized the lag, maybe they've figured out how to use that data too. Maybe. BTW, there's a really good book on the principles of engine tuning by Jeff Hartman. Also, the manuals for the programmable EMS computers are mostly available online. They give a good overview as well. But nothing beats doing an engine yourself. I learned more with my Haltech than I could ever have by reading about it.

I managed to get my hands on an actual Bosch .pdf explaining exactly how the 5.X and 7.X work. I should dig it up and throw it on a server for download. It is the most comprehensive break down I have ever seen published (I just can't regurgitate verbatim) B

Pushing it to a server now

I'm only going to leave it up for an hour or so while I deal with a customer. Blue, download it, I'd like to go over some thoughts with you offline.

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Got it. Nice.

It all makes sense. But I wonder if the DME just makes small corrections to one load/speed point on the map at a time or if it tries to smooth the map around the point of correction. The O2 sensor isn't fast enough to relay good data while the engine is dynamically changing, like changing loads or RPM. It needs the engine to be steady for a while to know what the conditions are at the intake relative to the exhaust. Although, I suppose if they charactorized the lag, maybe they've figured out how to use that data too. Maybe. i doubt that the dme is sophisticated enough to incorporate the 02 sensor lag into analysis, nor to interpolate the curves. rather, i *think* it tends to apply the stft to 'regions' of the maps - idle/coast, under load, wot, etc.

This is perhaps one of the most interesting threads I've come across, regarding boxsters. I'm hoping there is more info on this subject to come. Brad is there any more pictures of the air cleaner box after the modification , as it would be very interesting to see, pretty please . It's nice to see for a change no one ********************ing or telling you guys you have done it wrong or you don't know what your doing, lol. A DIY for this install would be fantastic , and interesting. Keep up the good work.

Want to know why shop owners stay off the forums? We get tired of being told we are doing something wrong by an armchair engineer who has owned one Porsche and has only worked on HIS car. I speak with Porsche shop owners world wide on a daily basis (and Boxster owners nationwide) I tell everyone to take in all the information you can, but QUALIFY the person giving out the information (what do they do for a living?) Luckily.. in the Boxster community, you have a LOT of smart people that solve problems!! other Porsche communities are sometimes lacking In the picture below, we trim off what is the "muffler" We trimmed this first one back a tad too far, but did not get into the actual airbox. After trimming, you will see this "hole" that leads into the air box (or MAF housing) B

This how I patched it: We use a ton of 10/32 allen screws to attach body panels into nut sert plates, so we used two of them here with nylocks on the back to secure a small alum plate we made Can a plate be fitted 100 different ways? sure.. pick your path. This took 10minutes max. B

Thanks for the reply Brad, Am still a little confused . We cover that hole, Why ? And what happens with the large cutout we have just made. I'm definitely no mechanic, just trying to learn how things work so if they make sense to me I can then make a decision to try them or not. Thanks for the help so far.

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The hole is open to the engine compartment after removing the back side of the assembly, past the air filter. So you want to cover it so nothing gets sucked directly into the air stream and MAF w/o being filtered first. I have the same looking patch on mine. If you look at the pic's I posted, the 2nd one shows the portion that was cut off, right behind the tube that comes out from the assembly past the main housing. Hope this helps.

Thanks Flyer!! I didn't decide to take pics of ours until *after* we had cut the box off

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I am struggling with what the contribution of a software remap is to engine power after one has increased air flow rates (without hurting velocity) through hardware changes. If the 25% value is correct, the stock map will adapt. I can understand remap benefits for where ignition timing is refined for a given fuel quality (anti knock rating). What other benefits can a remap hope for? Also wondering what power increases everyone has realized with the 987 box. I would expect its real value would be seen on a 3.4 and 3.6L where you may start to get significant vacum readings (MAP) in the intake system. I would only expect a minimal gain on a 3.2. Perhaps I am wrong...just trying to learn. Will my stock air box be good enough up 290 hp or so? Is MAP data via OBDii good enough to see what is working?

manufacturers will compromise air/fuel ratios and engine temperature to improve emissions. often the biggest power tuners tout comes from bumping up the rpm limit (if hp is on an increaseing curve, you will get a 'gain' in hp by alowing the curve to travel a bit futher).

I have 4 CaymanS engines apart right now with the number 6 rod bearing toasted!!! Please please keep raising those rev limiters!! LOL It'll keep me in business longer!! B

Here is what I know: The 3.2 uses a head nearly identical to the 3.4 The 3.4 makes 300hp stock The 3.2 makes 250hp stock Porsche CUTS THE NUTS off of the Cayman's and the Boxster's If I use the same size exhaust and cats from a 3.4/3.6 on a 3.2 and utilize a 3.4 Cayman Airbox and a 3.4 sized throttle body, I *should* be able to make 300hp out of the 3.2 engine without compromising anything. We have already made 250 with a 2.7 with little to no mods. 3.4 has the 3.2 crank with just smaller pistons in the 3.2 3.4/3.2 cams are identical.. (they say 3.2/3.4 on them) I have the 3.2 car I'm going to test all of this on, and I have a base tune ready for the car based on a 3.4 tune. As some of you dig in deeper to the ECU's you are going to see the BIG cam timing difference between a 3.4 996 tune and a 3.2 986 tune. Then again with the 3.4 CaymanS tune and the 3.6 996 tune. B

We have already made 345hp with a stock CaymanS engine and I have other shops with 350hp. We made 345 smog legal with all four cats in place. B

Hmmm yes a little more power just at the top won't help me much.... Yep I know a Cayman guy that looses at least one engine a season.....they dont like over revs. For those that have the Cayman box ....how is the proper reprogramming for the larger MAF housing accomplished

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Sounds great...Thanks for the feedback Same heads??? Wow!

From a manufacturing standpoint.. they will only cast a few parts. CaymanS 3.4 uses 3.6 heads.... (they actually say 3.4/3.6 on them) So? why would a 3.4CaymanS only make 300hp? when the 3.6 makes 350? (Porsche cuts the nuts off the mid engine cars) B

Brad Just thinking out loud. You may have to consider the merits of the 3.4 intake runner and plenum (left and right) acoustic properties to get the 3.2 to breathe.

I encourage people to think out loud The 3.4 plenum is taller, but the actual design is not much different (I have about 30 intakes from 2.5-3.6) B

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I was thinking of using the 3.4 setup on mine, to go with the airbox and slight bore increase. Sell me one cheap?

My 3.6 could use one too! Currently using a 987 MAF tube and a BMC DIA 85-150.

So what's the next step in the process . You cover the hole, then ? What happens with the large cutout section, please, Thanks

I throw the large cutout section in the trash It's a box. The hole being covered is one way in one way out. Cover it, and no air will bypass the filter. We are cutting off a sound chamber/muffler. It is not needed. I wish I had shot a picture of the air box prior to cutting... I may pull the one out of a CaymanS in the shop right now for an engine rebuild just so you can see the before and after. Guy's.. buy a new one from Porsche. Trying to find them used right now is going to be difficult. I posted the part number and the price in a previous post. They are not expensive new. B

got a question - why are we modifying oem air boxes instead of going to say a bmc carbon dynamic or direct air unit? is it to stay within scca regs?

Porsche has more engineers than both those companies combined X5 The BMC stuff is a compromise, just like the Chinese headers. They make one size to fit all and typically.. it is too small. You know: The stock CaymanS box supports 300hp stock. I have personally dyno'd and tuned this box to 420hp in X51 Cayman's. We have made our own tubes/air boxes.. too much work.. I can buy this from Porsche and with 15min worth of mods to the box, it bolts in. I have used the other stuff. The best one I have seen on the dyno is no longer available and was nearly 4x times the price of buying a stock CaymanS air box from Porsche (new) B

Plus water ingestion and FOD problems would be better dealt with. I believe there many models that use this airbox starting with the 550 spyder 986......going all the way up to the present day Cayman S....not sure about the base Cayman and the R. I started to modify my stock s box but have stopped.

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I guess with the 3.4 tune you have the proper MAF housing calibration for the larger Cayman housing....oh yeah and just going through all the posts now.....looks like it is plug and play. It wasn't in my head though!

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Sounds like you are just lopping off a resonance chamber for sound attenuation and are left with the entrance hole to the chamber from the primary airway.....and have to block it up. This move may reduce turbulence

Hey Brad, I believe the '04 550 Anniversary used the same intake (part # 987.110.021.00). The extra bump in hp was partially attributed to the intake. Do you have any idea how they got it to fit in the '04 Anniversary without cutting the airbox? Pierre p.s. If anybody is looking for a Cayman airbox, DCauto has a used one for $200. For $367, you can get a new one from Sonnen Porsche in the bay area.

Hey!! I know you Interesting... very interesting It shows that Porsche used a 993 MAF holder in the 04/986 chassis compared to a 987.606.125.00 for the CaymanS Looked at the Yellow GT3.. spotless.. easy minor damage no tweaking B

The Cayman tub is shaped slightly different right where the crossover rail meets the frame rails at the back of the engine compartment. It is more flat along this wall (see arrow below)

Stock 2.5/2.7/3.2 air box.. B

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Thanks for the pics. I can see how the 987 airbox would have a problem fitting. I wonder what they did to get it to fit the '04 550. If I see a 550 at one our PCA events, I will ask the owner to see if I take a peek under the engine cover. I put my hunt for 6GT3 on hold. My wife now wants a Mini Cooper instead of a GT3 :-( Go figure... Pierre

Hi, if I was to go down this route and change the air cleaner, box from the 986 to 987's. I would also like to get the IPD plenum and larger throttle body, my question is which IPD kit to order as the silicone hose from the MAf to the Throttle body will be different from what I can see in the pictures (ie) the throttle body is in a different position on a cayman requiring a shorter hose ( than the 986 kit ) . Hoping someone can offer some advice, please. I have a 2001 2.7 986.

Thanks for the pictures , Brad. The thread seems to have gone quiet, lol. I was kind of hoping someone would give me an answer to my last question, regarding the ipd , larger throttle and what hose setup I would need to order. Any thoughts would be much appreciated. Bye the way the 987 air cleaner is cheap at around $360 , its the new 987 maf housing thats expensive as it costs about the same as you have to buy the sensor with it. Thanks for your help thus far.

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I was going to use an IPD setup for a 3.4 Cayman S, when I recover from my engine rebuild bill. May be a while. Now looking into using stock setup from Cayman S, there is a thread on doing just that somewhere....see if I can find it. For now I'm going to run my stock 3.2 stuff. Will report back when i get it running, should be by this weekend, I hope. http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-2.html

Thanks Flyer

I highly suggest the IPD and CAYENNE V8 throttle body (much cheaper than the GT3 and its the same size) All those people buying the "GT3" throttle body are being raped.. LOL The V8 throttle body has the connector oriented just a tad different than the actual GT3 B

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Thanks for the tip, nice of you to share all this info for us & me. Any year Cayenne V8 will work?

948.605.115.03 Don't laugh.. full pop retail from Porsche is ..... $284.00 I'm very lucky that I'm exposed to a LOT of Porsche cars/parts. It takes a VERY long time to learn this stuff. B

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so I finally got to drive my car again, first impression of the 987 air box is a plus. Makes good sounds too. I will have a final install pic in a new post with all my engine mods to date soon. Need to break in the engine first, but I can tell already that it rips!

Congrats! Are you able to say whether the DME properly adapted to larger MAF housing diameter?

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Not yet, it was a short drive of about 2.5 miles. Had to unplug the maf, seems to have failed since it was siting in the garage.

Thanks for the update, look forward to your next report. Keep up the good work.

Lots of good parts left on that wreck!! Paul doesn't say much does he? B

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Ordered a MAF off ebay, I should know better, wrong part and its used. Drove it on the highway first time anyway, pulls real well. Still waiting to have the proper MAF installed, then I will follow up again. Snow this week.....

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I offered him $100, he said no and countered with $200. No sale....YET. BTW I posted the pictures in hopes you could better show us where to make the cuts.

Any thoughts in putting the rest of the Cayman intake in right up to the diverter tee? How could one run the diverter flap? I suppose a Cayman tune would be needed...

THolyoak used this airbox on my M97 3.8 986 swap back in '09. He said at the time that no modifications were required to get it to fit in the chassis. Would I gain anything by bypassing the referenced "muffler," or does that just alter the sound? I am running the 3.6X51 DME map (as it is the largest engine size that was available on a "stock" Porsche 7.8 DME tune/map). Always wondered what I am leaving on the table by not getting it professionally tuned. I also have a 3.8 IPD kicking around that I never tried. Any ideas if these two mods would give significant gains? He thinks/thought "no" at the time I picked the car up back then.

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Nice looking installation! How much did that set you back? If the muffler fits in your bay I would worry about it....I had thought it would only go in a 987 or was there a special 550 spyder edition box that you put in? I was specifically referring to the Cayman diverter tee and how to make it work on a 3.2 M96. Where did you get the hose on the tb ....looks like a good fit

Any updates, gentlemen?

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I think we are still working out MAF housing issues. Still trying to put my hands a reasonably price air box and MAF housing from there I will be able to see what can be done It looks like hell to get the old box out and the 987 in!

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This box looks a little squarer at the back than others I have seen. It may fit better. Different model? Perhaps it is my imagination!

Brad, What does the end treatment of 987 airbox look like and can it fit up to a smaller bosh (3" dia) MAF housing?....well without it looking like a boch job and introducing losses. It may be a good set up for those not running a custom tune (3.4) j

Standard 987S airbox, and generic 3.5" silicone TB hose both from ebay IIRC.

Not sure the 986 or 987 3.2 or 2.7 will benefit from the 82mm tb of the 997 carrera 3.8/gt3 . There was a guy that tried it over in australia and he thought it actually lost power. Fitting the 74mm unit with a silicone intake and cone filter is probably the best solution for a 986 , as removing the air box is much easier than on a 987. The 986 definitely has a stunted performance from the smaller air box and media area , hence the 986 550 anniversary gained power from simply fitting the 987airbox and filter but keeping the 68mm tb. The later 987. 3.2 and early 2.7 987 both used the 68mm tb from the 986. The later 987 M97 engine 3.4 and 2.7 used the larger 74mm throttle body. There is a thread running on planet-9.com relating to a cold air silicone hose and cone filter upgrade for the cayman that suggests significant gain over the 987 air box. This may be worth considering as an alternative to the hassle of buying and fitting the 987 air box to a 986. There may be issues with the maf housing diameter as the 987 uses a larger size and a different type of sensor I believe.

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Yes well put...welcome to my world! I am wrestling with this right now. I have the 74 tb and plenum in place but I am trying to determine the real merits of the 987 box over making my own intake, sealed to the scoop of course. Making your own is much, much less hassle. I was suprised to see the Caymans making more power with the cone. Perhaps it is down to the filter element itself. The main advantages of the 987 box are the huge intake area of the snorkels shaped to the scoop and box volume. There must be some hard to see restrictions inside the box. Actually this huge snorkel may be of use in making my own intake....running to the drawing board now!!

I personally believe the 987 OEM filter has one big advantage in that the larger filter area over the 986 (14.5 sqft vs 6.1sqft) not only gives a lower pressure drop but also a significant longevity to the element. In other words the element maintains the benefits of the lower pressure drop for a sustained period as it takes longer for the element to be come contaminated and restrictive. This type of cone filter is normally used in race applications where the filter is either replaced or cleaned and re oiled after a relatively short period (ie one race). Providing the cone filter can be located somewhere accessible and the owner is happy to clean the element frequently , the next issue is contamination of the MAF from oil carry over. An air box and indirect route to the MAF should reduce some of the risk of oil contamination as the oil will drop out of suspension in the air at lower velocities where the diameter of the air tract increases and velocities reduce. A silicone hose direct from the inlet cone filter doesn't allow the velocities to drop so the MAF is more at risk from contamination. I believe there were revisions on the MAF design on both the 986 and between 986 and 987 whereby additional screens were placed in front of the element on the 987 to protect it. Of the cone element installs I've seen , they all seem to rely on removing the baffle plate in front of the air box to give better flow. Whilst this does indeed work it also increases the risk of water droplets getting onto the MAF or in extreme cases making the filter wet and losing capacity. I think that to make a satisfactory street version of an intake system all these elements need to be considered. If the aim is purely to make a track orientated modification then a cone filter and silicone tube will give the best results for minimum outlay.

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Yes the 987 filter is massive; the biggest I have seen. I think if you were to adapt a smaller MAF housing to it, the cumlative losses would still be a lot less. I believe that large volume airbox designs are considered to be the most efficient perhaps because they have a huge volume of high static pressure air to draw on right before the filter. I am not sure high velocity all the way is the best thing. It is just that this 987 air box set up has a MAF housing dia that my DME may not be expecting. I am not sure I understand what you term the baffle plate....the air box wall at the end of the scoop air duct?? I personally would not put an unprotected cone in the air duct for the reasons you outlined. I had envisioned a snorkle or duct sealed in scoop air duct via a "baffle" plate or heat shield. There would be no air injestion from the engine bay. There would be a 90 degree bend to knock out water leading, uphill to a sealed BMC oval trumpet or CDA airbox. The MAF housing could be placed behind another 90 to further protect the sensor. The filter would be accessible in the engine bay. I have yet to hear anything substancially negative about the BMC air box set up be it maintenance or performance. I imagine the filtering would not be as good as paper elements. Yes I believe there have been revisions the sensor but you need the DME update from Porshe to run them. They may ruin you custom flash if they hook there diag. tools.....I am not sure of the cost of this update. So I guess you need to be working with a stock flash to get the updated more robust sensors.......

Hi, Just to clear something up for me, if I put the 987 airbox on my 986 2.7 , I can still use my existing maf sensor on the new larger maf housing with no problems ? My plan would be to do the airbox, ipd plenum and larger 74 mm throttle body. Can anybody see any issues here and would I have to do any exhaust mods to compliment this. Mine is stock apart from a sport muffler( silencer) . In Australia we don't have the pre cats either just the rear ones. I would appreciate any opinions , within reason, lol. Thanks.

To be honest I would fit the 996 3.6 inlet tee rather than the IPD plenum to mount the 74mm throttle body and then fabricate my own hose to connect to the airbox via the MAF. The IPD plenum is an unearthly cost and gives very little benefit in its own right. Ideally i'd suggest the MAF should be the later type in the larger housing , but this requires reconfiguring in the DME I believe. With the original MAF and housing you risk the MAF becoming a restriction and ofsetting any gains from fitting the larger throttle body and plenum. The MAF will have a set range its allowed to accept in the DME, force too much air through it and the DME can throw a fault ,though i've only ever experienced it on a tubo car. good luck with hte mods , it would be interesting to see the result you come up with.

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This seems to be the very problem I am having with my 987 box in my 986. The MAF has the proper voltage, but I keep getting a CEL for MAF. And I cant get it smogged as a result. I started another thread trying to explore all of this.

Hi Once, What about trying your old Maf sensor from the 986 airbox. I thought I saw Brad say you should use it and that it fits. Just a thought. Brad has been quiet on here of late, I hope he's ok.

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I did try that, it fits the same yes. Turns out the tube is too big for the DME to compensate for it, so I stuck some foam in there to reduce the size a little. Seems to be working so far, no CEL.

Hi Ona, I'm glad it's at least working even though it's probably not exactly as planned.

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Passed the smog test, removed the large foam and replaced it with a much smaller one. All good now.

I just got my 987 airbox in the mail the other day. I am waiting to take my hardtop off to tackle trying this box out. I think it will be a good addition to the 3.4 in there now. I will take photos and keep people up date if anyone would like.

Wear gloves, this job will slice up the backs of your hands!

Thanks for the thought of my hands. I am going to pull the intake manifold on that side and then there should be no worries of the hand mashing.

Just finished modding two boxes. One is going in the 3.2 I mentioned early. I'll go to dyno this week with the car. I found something else interesting during all this that I'll share this week also. The MAF you want to run is the .125.01

Yeah, I"m interested keep us updated. It's all interesting JAAY & Brad

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Thats the one I used also. Works great. The one from the 987, not so much.

Brad. Why the .125.01? I mean what is saying to you better or not? Better afrs?

The 125.01 is the updated MAF that we all run in all of our FBW cars. It appears to be a more robust MAF, that is less prone to failure than the 125.00 I have been told numerous times that it needs "programming" to work, but I haven't seen a need in the last 4 years we have been selling them. The engine is going in the -S today. We finished the engine build on Sat. B

Command decision made: If we are going to install a 987 air box.. why not switch it over to the larger CaymanS 3.4 throttle body B

efrwerw

weew

Now.. think about ALL those guy's who have bought the IPD plenum setup. They ALL have these parts sitting around (the TB and TB center section) FYI: This is not new by any means. Porsche did this EXACT same setup in the 986 50Th anniversary car. Granted it was a Variocam Plus engine, but it was still a 3.2. Something else.. scared of the larger throttle body? The rubber bellows from the MAF housing to the throttle body? They sell two versions. One for this 3.4 throttle body and one for the 2.7 cars (same one they used in the 50th anniversary 3.2 car) B

I think it's a good idea to "help" this area (with a hammer) I didn't, but it would have made it easier to the install the bellows from thew MAF housing to the throttle body. Just a little nudge!! This is were the 86 and 87 chassis differs. They have more room right here. B

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As one of the people who has bought the IPD plenum - could you please elaborate on your point. Are you saying I made a bad selection or a good selection?

I'm referencing the IPD purely from a used parts standpoint 987s owner who bought the IPD will have the throttle body T section (and throttle body) available for sale (since they removed it and installed an IPD) The 987 3.4 T section allows for the 3.4 throttle body to be installed in this situation for a lot less money!! Want to go bigger later? Buy the 3.6 T section and install it into the 3.2 plenum, its the same diameter as the 3.4, but allows for the 3.6 throttle body. Just giving people alternatives B

Thank you for the clarification buddy...

For all you with children you know how difficult this is. I had a about a 2.5 hour window while little Lily was sleeping this morning. So out to the garage with some tools and the baby monitor. Recap - My motor is a 996 3.4 so not the nice bolt up situation because of the cable throttle body. So I had to do some extra slicing and dicing. Here are the photos so far. This is as far as I got until the baby monitor called me in for sandwich time. Untouched Planning my attack First slice

More cutting needed. The outer plastic around the main tube had to go, maybe didn't but It sure makes it a bunch easier to work with more space After the extra was gone

To catch you up to speed I did some preliminary test fitting. I removed the drivers side intake manifold and the fuel rail was removed also on that side. I probably not need to remove the fuel rail but I did. You will notice in the pictures to come that all the open ports were taped over and filled to keep the crap out while working in there. After I fit the box in there I test fitted my mass air housing. I am using a bmw housing, talked about elsewhere. So being that is not a direct fit I chopped off the oem connection point on the air box tube and fitted a silicone coupler that was previously used on my IPD piping (for sale now) and secured it with a T-bolt clamp. before after

I did clean up all the edges with the cutting wheel and a file so now they are all pretty. Sorry I didn't take a pic of that. I have not made a a patch piece for the muffler section yet. When I head out today I will pick up some apoxy and use a piece of the cut up box that is readily available right now on the floor of my garage. In the car Test fit of the maf. Still needs a clamp on the maf side. This is where I am at for now. Maybe later on this evening after hours (baby sleeping) I will head back out and put the manifold and fuel rail back in. Side note: Anybody know if it is ok to reuse the injector o-rings? There in good shape, they were replaced when I put the motor in. If they are reusable, should I oil/lube them or anything? Thanks for the info on that. J

Nice work Jaay.....suprised you didn't just use the cayman MAF housing as you are a 3.4......unless your tune requires it Actually they are really pricey so this may just cause and your reasoning

BMW+Ebay = cheap :O) .. Not that I am trying to do my car cheaply but I have spent enough on this car. These are just the finishing touches right now. Thanks for the kind words.

Can you calculate the flow area of the grilled ellipse leaving the box going to the elbow section?

I will measure it for you, gimme a minute.

roughly 6 1/2" x 2 1/2" opening

Cool even major and minor diameters would be good.....yeah bosh MAF housings on eBay are definitely the way to go

Do you want other angles ? posted 2 down the sizes.

Hmmm just the outer dia of where you cut off the MAF housing boss....as in what hise size goes over it and seals

3"I/D About 3 1/16 O/D

A quick search through the parts catalogue suggests the only difference between a standard 986 and the 550 aniversary is the air cleaner housing and the MAF , the rest of the inlet system , engine and body (save trim parts) remains the same. The 987 MAF is supplied complete with the housing which bolts directly onto the air cleaner , the connecting pipe to the throttle body is standard , there is no reason for it to be different as the TB is the same 68mm unit on the 986 as it is on the 987 3.2. The flexible boot used on the 987 to connect MAF to the throttle body (its located futher back from the inlet manifold due to the split intake plenum after the throttle body) is the same part on the 68mm throttle body as the later 76mm unit found on the 3.4 (it just stretches slightly more). I am therefore surprised that if the 986 and the 550 are essentially the same body, chassis and engine why does the 987 air cleaner need modifying ? Is the 550 shell modified during assembly ?

Yes I have been wondering about this for a while ...perhaps there is an early version which has a truncated muffler area. There is a picture in this thread showing a muffler area that appears much more square. It would probably help to get it in with the engine in place.....Jaay must have every knuckle skinned right about now!

no cuts or scars yet! With removing all the stuff I mentioned out of the way and cutting the excess off the new box it was not that big of a deal.

What's the latest with your install?

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Nice how are you properly running the diverter flap in that Cayman diverter tee? Looks like you have a line going to the AOS for it as well. Which MAF housing did you end with? Perhaps you've loaded a 3.4 flash to have the DME run the extra flap and accommodate the larger MAF housing?? Just curious....I only see one Boxster engine and have to guess at things!

Sorry I have not updated. It has been in the car over a week and it is running flawless. No codes etc.... What is amazing to me is that the 987 air filter has to have at least 2 to 3 times more surface area. The thing is huge. It was a bit of a pain in the butt to get the piping to fit the way I wanted. Like you know I don't have a typical 2.7 or 3.2 so my plenum sits differently. I was able to cut up the IPD silicone pipe I had and use that with some t-bolt clamps and got it all to work with the BMW mass air housing I am running. Using a beemer one because it was cheaper than a cayman one and I didn't need the mass air sensor itself that comes with it. I have yet to put my wide band back in but I may do it this week. I will let you know if it is running any differently. I can assure you thought that it is running real strong. Schoir can vouch for that. Let me know if you have any questions. J

Sounds good yes I will have the same problem......my tb will pointing the wrong way! Be sure to snap some pictures next time you have the engine open

Bump My favorite topic of past few months, but as a non-engineer, hard to figure where this ended up & decipher. I have a '02S & would like to know what is the best option for more performance without breaking the bank -- appreciate the insights throughout but still a bit over my head. Where have the knowledgeable folks ended up on this 987/Cayman air box? Is there a combo that makes most sense for the 986S crew for better performance than stock? Bonus Q: In PA, not near Brad in LA area, so any shop near Pittsburgh that it would make sense to approach since probably beyond my limited skills?

Bark. I'm not too far and would help with what ever you need

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Brad, How are you getting 250 HP from a 2.7 with little to no mods? I have a 2001 and I feel like a moving pylon at the DEs against all the Caymans and 996s in my run group. Thanks

Is there a muffler in the 986 air box? If so can it be blocked also? Alex 01 Boxster S 08 Passat 2.0T 92 FXSTC

jmitch, I think what Brad was getting at was that the 2.7 has, over the years, gotten a bump in power from the factory without really being heavily modified. The latest iteration of the 2.7 was putting out around 240hp before they went to the 2.9, which is nearly the 250 that the Boxster S had back in 2000 with the 3.2. I'm sure it wouldn't take much to coax the rest of that power out of it when it's nearly there already. For that matter, I'm sure Porsche was simply undoing much of what they did to restrict the engine over the years to let a little more power out and keep pace with the 911's increases. Unless he is talking about an earlier 2.7 that he has modded lightly to produce better numbers, in which case I second your question.

Any further updates? TIA!

what do you guys think about this: BGB / Fabspeed Cold Air Intake Install (with Pics) - works for the cayman, so will work for the 986 as the chassis is the same in this spot (would require different silicone as the throttle bodies are in a different place). expensive, but could fabricate something real easy; do as another member did on this forum and use that rubber boot that is removed in the link above as a template to make the plate out of lexan, attach one of these: RX-4750 - K&N Universal Air Filters, Universal X-Stream Clamp-On direct from K&N and then 3" silicone to the maf housing (reuse the oem unit) and throttle body. do you think there would be any issues with water, etc.?

To think of all the trouble I went through to put in that airbox he cut in half....I think I'll leave mine as is now. Plus, It looks like a total PITA to get that new filter out to clean it.

Installing 987 airbox in my 986. Does anyone have a 987 S MAF tube for sale? OR anyone thinking of buying a MAF sensor & won't need the tube? PM me.

What are doing to adjust the MAF housing diameter or are you doing a tune? It's tricky to find one of these as a 987 take off as the correct size housing is required to have the car run properly. ...I need one as well

I used a 2000 540i bmw housing. Cheap from ebay. Mine works great. I by no means have stock piping but It is working for my application with out a hitch.

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I would like to avoid cuting off the end of the 987 airbox. I plan to flash my DME with the 996 flash & tune from there as needed. It would be easy to cutoff my 986 MAF tube & plumb it in but I want to keep it as oem looking as possible for CA smog checks. I know there are 100's of disgarded 987 MAF tubes laying around 987 owners garages.

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Will the BMW tube connect to the 987 airbox?

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Okay hopefully the 987 housing diameter matches up the the 996 tune requirements...it is around 3.25" as I recall. Let us know how the tune works and there is problem running it on a 3.2L and all the ramifications I wonder what they do to replace them with and why?? I need one but I plan to sleeve it down to match the 986 3.2 DME

not alot available for aftermarket intakes for the cayman/987 (already is a very good cold air intake) so not many used mafs on the market. the place to ask is via a wanted ad at planet 9. ps, if you are gonna push a new base tune on your car, try the 996 x51 tune - raises redline by 200 rpm.

I have been following this post for a while now and it is a very tempting mod. I have a 2000 boxster S 6 speed and was hoping to get some direction from those of you who have done this. I recently acquired a 2007 cayman S diverter T and throttle body and would like to build from there. I have a few questions perhaps some of you could shed lite on. 1- What do I use for a vacuum signal for the flap in the T 2- do I continue sourcing the rest of the 2007 cayman S intake, MAF, and air box 3-From what I gather from the post, I use the maf sensor from my old setup installed in the cayman s MAF tube and my DME will adapt, if not will the X-51 flash help. Thanks for your knowlege and advice Frank

1. i *think* you should be able to take the vacuum signal that drives the resonance flap on your intake and use it. if you look at your intake there are two tubes that join the two sides together - the diverter 't' and the resonance tube. on the resonance tube there is a vacuum-driven flapper valve. 't' off this vacuum signal to drive the flapper on your diverter. 2. personally, i would just connect the new diverter/throttle body to your existing airbox/maf housing to start. this way your car can work with it's original tune and you can see if you get any performance improvements, if the flapper in your diverter is working, etc. 3. if you do go to the cayman airbox, you can saw-off the maf housing on your original airbox and plumb it into the system, or you can use the cayman maf housing and see if your ecu will adapt, or you can push a 996 tune onto your car (designed for the larger maf housing). only the first is certain to work; i've not heard with any certainty that the other two will work.

The 987 and 986 have different ECU programmes (and ECU's) , even though they share the same heads and much of the internal engine parts. If you fit a 987 inlet plenum T its supposed to modulate independently from the cross flap that is in the other link tube between the inlet manifolds. Unless you get a custom ECU I cant see how you could get the plenum T to modulate correctly , so it may be better to simply fit the T without any control. I also suspect that the variocam on the inlet also adjusts based on the plenum T as would possibly ignition and fuelling. Assuming you are fitting the airbox as a performance modification, it may also be better to fit a cayman / post 2006 boxster plenum T rather than the earlier 987 boxster 3.2 model. The later model plenum used on the M97 engine uses the same airbox but has a larger throttle body ( 76mm rather than 68mm diameter). I would still sugest this is fitted without the vacuum control or if possible with a 996 3.6 manifold T which doesnt have the internal flap control. If you fit either the M97 76mm plenum or the 996 3.6 item you need to also fit silicone reducers to mate the T to the inlet manifold on each side as the diameters are about 10mm different. There is a write up on planet 9 under the articles section and a few posts on 996 plenum tees into 986 boxsters under the tuning part of the forum. Hope this helps.

I would also be concerned as to where the flap is flapping without controls attached to it.

I have the complete set up from a 2007 cayman S, Air Box to intake T. Still doing my homework on this, just trying to lay out my options before I do the install. I'm busy with school rite now and I have suspension upgrades planed for spring break so this project is on the back burner until I can more info on the update. My main concern about this is the MAF and what I may need in the way of programing in order to benefit from more air. I would like to take advantage of the flap in the intake t for low end torque. If the intake flap is actuated with the variocam I may try hijacking the signal from the variocam solenoid relay to actuate a relay for the additional vacuum solenoid. I may put it off until I can get some head work done. I recently saw a post on the Pelican Bord from someone who had adapters made to use the cayman S intake manifold on 996 heads. In case you can't tell I got a real bad case of cant leave well enough alone!

I make adapters to install the CaymanS intake on *any* of the 9X6 heads. The guy who *probably* posted on PP was a guy out of San Antonio we did a set for.

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I intend on manufacturing a press fit sleeve for the 987 MAF housing. To bring it down to where the 986 tune can work with air flow. This diameter nicely matches the dia of the 987 74mm tb. This way I avoid custom programming issues The 987 T flap is vacum operated. It may be that the vario cam change overs their signals could be made to run the flap and work but I fear you will get snap change in flap position as the cams phase (2500 rpm ?). Maybe this is okay as this a coast cruise rpm but if the phasing occurs at (4000rpm) you could be in the middle of a corner when you get cams and flap changing.....whomp! The 987 would have vario cam plus which is gradual. Sounds interesting let us know how you make out!

The rate at which the flap opens can be regulated by the diameter of the vacuum line that feeds the flap bellows, larger diameter more volume transfer the faster the valve opens. The vacuum canister should have more than enough capacity to handle this. The plastic lines used currently have a 1mm I.D the combination of the small diameter and the volume air needed to actuate these devices does two things, regulates the time between normal and activated state, and lessens the affect of pressure pulses creating pulsed transition from normal to to actuated. Besides I have always been a fan of a 2 stroke like power curve, just as long as it is consistent. And I'm the only driver on this buss!

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Yes. True I didn't think about the line size and diaphragm diameter...could be okay! Hey I rode ported and polished RZ-350 for 7 years so I hear yah!

Finally got the 987 airbox & maf tube in & made a hose to connect to 997 plenum & 74mm T/B. Hard to see much of the hose, maybe I can get a better pic on a sunny day. My engine is 3.6L so runs very lean unless maf is disconnected then it runs ok just a little rich. Next is the 996 flash.

just thinking a bit here: anyone try to push a 996 flash onto a 3.2 986 that has the larger cayman maf housing? ie, do what you've done but to a 3.2? would really allow you to reduce restrictions in the intake tract, but the maps might be off for the smaller displacement (maf reading would be correct so afrs should be ok)? is there a special flash for the 2004 anniversary edition that had the 3.2 with larger maf housing?

I guess an 04 anniversary edition tune wouldn't work as it's a 7.8 dme. still, a 996 tune *might* work - afr's would be fine, maf readings would be fine with a cayman maf housing. I think it would just be a question of the maps being able to deal with the fact that the rpms wouldn't correlate to the amount of air (3.2 vs 3.4 displacement) but I think that there must be enough room in the maps for this, otherwise lne wouldn't be able to say that a 3.6 bore works fine with the oem 3.2 tune (same thing only in reverse). so, we need someone with a 3.2 to put a cayman airbox and maf housing in their car and push a 3.4 996 tune onto it and see if it runs ...

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That is my most recent plan for my car...though it is not a 3.2 anymore. We tried some updated tunes awhile back to no avail. Currently running an updated stock tune which is better than it was, just not great. Having the car on the road for over a year now, and dealing with various issues from the beginning I'm ready to once again try and make it right. Looking at putting the IPD plenum and a 987 TB on it too. Will report back once the 996 tune is tried.

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I think it would run ok just possibly a little too much cam too early due to the 996 timing. I would have to compare the cam timing differences.

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996 flash works great for the 3.6L, I was surprised how much power this combo added! The intake roar is startling! New dyno test coming.

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Who did the 996 flush for you if I may ask?

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I did with my PST2

I am impressed. You are the man BYprodriver. Respect, respect

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good to know you have one

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When I reflashed mine, I got to see some of Porsche's humor while the download was taking place:

That's harsh ....I think a more encouraging message would appropriate!

help! help from the gurus who have installed a cayman airbox without dropping the engine! i've modified the air box to remove the muffler. i've removed the intake. i've left the fuel rails on at this point, and CANNOT fit the thing in. any tips?

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I am dreading this myself and have not done it.......You may have to pretend that you are changing the front engine mount and sneek the front of the engine down a couple of inches....yes I know didn't follow instructions Perhaps leaving the lid off will allow you to contort it and snake it around the side of the engine.

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It's a pain & I don't recommend enduring this project for 3.2 or smaller till the engine is out. I removed the intake & fuel rail. Bend the engine lid mounting tab straight up for more clearance & remove the airbox lid filter & snorkel. You can reinstall the snorkel, filter & lid once you get the box bolted in. It would be much easier with the MAF mounting flange sawed off, but I like the larger MAF tube & works great with a 996 reflash

[QUOTE=Paul;334848]When I reflashed mine, I got to see some of Porsche's humor while the download was taking place: Thankfully my 2000 Box IP doesn't have that "big screen" option.

ok, i'll pull the fuel rails tonite (wanted to avoid it as my garage is sealed for the winter and fumes will be an issue); thanks for the tip on bending the tab up - it is one of the bottle necks. edit to add: given my luck, i'll probably snap the tab off in the process ...

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get a 1mm-2mm rubber cap/plug/stopper for the hard fuel line attached to the body & disconnect the supply line to the fuel rail. Cap the main line & drain the fuel rail into 1 litre catch can. Bend fuel rail over to opposite side of engine. It's really tight to cram that 987 airbox in place. The tabs are good steel so they bend back & forth well.

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Pro, So there is no way to get the box in with the MAF flange and clips still intact? I had planned on keeping these for a stock installation appearnce. What about lowering the front of the engine al la front mount change? What sort of pumbing did you end up with from the end of the 987 MAF housing to the the TB? I have a 997 diverter tee and this intake tract route was a real pain last itme around....having no garage I cant linger, hum and haw with fabrication so just asking

I am using the 987 Maf tube mounted to the airbox flange with the oem o-ring seal & clips. The flange is what makes it hard to install the airbox past the oil heat exchanger. Once you get the box bolted in you can install the MAF tube. Hard to see in this pic, but the widest clamp to the right is clamping the hose to the MAF tube:

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Thanks, yes I see it. It looks like you are using the stock 987 rubber piece at the MAF housing. Yes I wouldn't try it with the MAF tube on....so not possible with clips and flange? I dont plan to saw off anything but the muffler

dude - he didn't remove the flange.

Yes but it's a 3.6 so presumably the engine came out to put the flanged airbox in....may not work with the 3.2 sitting there....or it's simply a matter of removing the oil cooler Need the detail so I can bang out the job in a day when the opportunity arises

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My Box has the original engine that I rebuilt 2 years ago & now displaces 3.6L. In a previous post I was giving RadiumKing tips on how to install airbox with engine in place by removing half the intake manifold with fuel rail.

Every time I work in that area, my hands look like I rubbed them on a cheese grater!

got it in - pull the intake, bend the tab - fuel rails stayed in ...

ok, what I think I've learned: 1. as per all the previous posts, air box will fit. it has a larger intake, much larger filter element, and larger output (3.25" OD vs 3" OD) - it is an improvement. 2. remove muffler. easy, messy work with a dremmel. get one of those automotive plastic welding kits from ebay ($25) to fix any mistakes you make. use a piece of the discarded muffler to weld on a plug over the muffler hole with the welding kit. 3. intake has to come off. 4. engine lid tab has to be bent up. thanks to byprodriver et al for helping me through the steps above. 5. there are two vent lines (I think they are vent lines) with a bulky bracket that sits right under the new air box. this bracket has to come off for proper fit. I am also going to saw off the stub bolt that mounts the bracket to avoid rubbing on the vent lines. 6. the oem air box mounts with three bolts. the 987 air box mounts with two bolts and a plastic press-on fitting. in the 987 the highest, furthest back mounting point is a stub bolt and the air box has a plastic fitting that presses onto this bolt. make sure you get this fitting when you get your air box (part # 987 110 141 00). take your original bolt, saw the head off and thread it into the mounting point. the new plastic fitting can press onto this. 7. the air box outlet has a flange designed to mate specifically to the 987 maf housing. realise that if you use this maf housing it has an ID of 3.25" so will not work with a standard 986 tune (the exception may be the 2004 anniversary edition, but this is a 7.8 dme flash and won't work with pre-2002 cars that have the 7.2 dme). options are (1) try a 996 flash (don't know if it will work, but will find out in a month or so) (b) get a custom flash (big $$$) or (c) use a maf housing with a 3" ID. for 3" ID maf housings, the easiest is to saw the maf housing off your oem air box. note that you lose the screen before the maf if you do this and should sort something else out for this. otherwise, many bmws use the same bosch mafs as porsche, so you can get a 3" ID bmw maf housing with screen and use one of those (I have model numbers if anyone is interested). the issue becomes mating the 3" ID maf housing to the flange on the 987 air box. easiest is to saw the flange off and get a silicone coupler that joins the two, but what I've found is that, while the air box outlet has an ID of 3.25", the flange itself has an ID of 3.5". I've taken a 3.25" to 3" silicone reducer and found that it is a press-in fit to the flange. to make it more robust I took a thin-walled 3.25" coupler and sawed-off a 1/2" band. I inserted this band into the 3.25" end of the reducer to reinforce it. now the silicone reducer sits very snug into the end of the flange. this is still a work in progress, so I reserve the right to change my info at any time. again thanks to the folks helping me with this. I think that 997 plenum, 987 air box, tb and maf housing, and 996 flash is going to reinvent the 3.2 for little $.

Sorry to all for the late discussion. I have a 2.5, and may I ask is it possible to change the airbox from Cayman S to the 2.5 engine? If it's possible, is it even to change the piston to the 2.5 engine? I realise the MAF for 2.5 and 2.7 is different. If that's the case, does it mean I need to also change the Cayman S MAF to adopt the Cayman S Airbox in the 2.5 engine?

Since the people doing this mod would probably know: I am trying to get some wires from the drivers side grille, through the airbox somehow and into the engine bay. When I was last checking, the stock airbox seems pretty closed up, even pre filter, and there is no where to sneak some wires through. Anyone who has taken the airbox out, is there some space I'm missing/a good place I can drill a small hole pre filter? Thanks

Anyone who has taken the airbox out, is there some space I'm missing/a good place I can drill a small hole pre filter? I don't remember any hole there behind the air box, it's been a few years. It might be possible via the "de-snorkle" option around it. I never did that, just changed the whole thing.

The Radium King, did you go to a 996 flash or stay with the 3" maf housing?

funny you ask - in my garage prepping for it as we speak. decided to wait until i have my new exhaust on to maximise flow before i do it. that means welding as i have an early set of the chinese headers and the O2 bungs are a little exposed. pm byprodriver as he's done it, albeit on a 3.2 taken to 3.6.

How happy have you been with the stock 3" up till now? Obviously you think there is more if you are going to flash after fixing the headers, but curious how it ran for you after the swap.

its running great - no cels , no issues. more power? no idea. i want to try the 996 tune for three reasons: - curiosity, - sems silly to me to reduce the intake diameter for the maf housing, only to increase it again once past the maf housing, and - 911 3.4 makes 300 hp. using the same ratio of hp:displacement, the 3.2 should be making 280 hp. the 3.2 and 3.4 share cams and bottom end, so most of the power must be lost in tune, intake and exhaust (those in the know say the 3.2 heads flow quite well, so no work needed there). this thread and ohers talk about upgrading the 986 intake with 987, 996 and 997 parts, and there are good, inexpensive exhaust solutions out there, so the last piece is the tune. if it works then you have a 30 hp gain with mostly oem bolt-ons. and for not too much money ($300 chinese exhaust, $50 for 1/2 hour labour to push the tune, $300 intake parts).

Hello guys, I'm planning to fit 987 airbox, butterfly and plenum all in one. Have all the parts, silicone reducers for plenum but missing how to connect from 987 butterfly to 987 airbox bit, is there a Porsche part for that? Plus it does seem that the engine bay is very very tight, can you confirm the 986 airbox can be removed without engine removal? what would be the removal order? 1-plenum 2-manifold 3-airbox? where are the manifold screws located? Sorry many questions.. photos are going to follow and I plan do make a brief video when will be replacing parts so others can benefit. attached my cut on the airbox. Cheers, Ser

Don't forget to cover the hole in the back. I used fiber glass. I had the motor out when I put my box in and it was still difficult then. I think it would be really hard installing with the motor in the car. I also had to cut off the flange closest to the throttle so I could get my 3.5" silicon tubing to fit on the air box. I installed a 996 3.4 motor in my 986 using the 987 air box but it was a really tight fit. If I would have needed another 1/4" it would not have fit. If you want some pictures I can send them. Good Luck

Brad I sent you a PM with a question. Thanks in advance.

Thanks to all. So at the end no one made this mod to a 986S with engine in? I really would like to avoid to remove the engine if its possible. cheers

I did it while I had the engine out, but the saying on the street is that it is possible with the motor in the car if you remove the manifold on the left side. That sounds very likely to me. But removing the manifold is not one of my favorite tasks, the bolts are hard to get to and be prepared to scratch the back of your hand.....

Thanks, feeling this is getting on the right track. Is there a manual I can refer to on removing the manifold next to the airbox side? Can someone please confirm the Porsche ID number for the tube linking airbox and throttle body? much appreciated

to plug the hole get one of these: 80 Watt Iron Plastic Welding Kit TPO TEO PP Rod Mesh Auto Car Welder Repair Kit | eBay and use a piece of plastic from the muffler you just cut off. there may be info on removing the intake manifold here: Porsche Boxster 986 (1997-2004) / 987 (2005-2008) Technical Articles | Pelican Parts otherwise workshop manuals are here: Manuals_Original only the driver side manifold has to come off. I couldn't get mine completely out because of the aos tube, but was able to move it to get enough room. use your dremmel to cut the old airbox into pieces to get it out. the new one will go in with some contortion - to make your life easier, saw off the tab at the back of the engine compartment lip as per reebuck1, and bend the driver side tab for holding the engine compartment lid out of the way. there is no oem tube to join the airbox and the throttle body. the 987 airbox is designed to work with the 987 plenum which has a big bend in it. the plenum you are using doesn't. you will either have to fab your own, or check with ipd - they make a tube that will join a 987 airbox to their plenum (which is about the same geometry as the one you are using).

I would advise you to take lots of pictures of every step and mark every electric connection that you open. I have to emphasize this. On an other note I would say that this is a fairly straight job. The manifold is held by 6 M6 screws that you use 10 mm socket on. They go straight down into the head and are a bit hidden under/behind the manifold. Be careful not to over tighten them when you put it back together. Torque to 10Nm (7.5ftlb). That is about the force you get with a big screwdriver. But I would strongly advise you to get a torque wrench for this job. And one more thing. You might want to open the hatch in the firewall, that is behind the seats, under the carpet to get somewhat better access to some of the bolts and get some light in under there.

other things I am remembering from the job - your intake manifold will also be constrained by the fuel rail - watch the injector tips. you'll also need part #6 on this diagram to keep the insall as oem as possible: http://www.********************************************.com/porsche-parts/hardparts.php?dir=987C-06-08&section=106-00 otherwise, you may encounter a bit of fuel vent line interference at the bottom of the air box; you may need to saw-off the fuel vent line retaining clip boss to get the air box to sit flush against the inner wheel well.

As promised, pics of the 987 intake transplant to 986S: A view over the 987 / Cayman airbox, cut to fit into the Boxster. Hole was sealed later reusing some plastic cuts and glue, plus thermo isolation tape. Starting opening the engine window

Part2

Hard to tell by reading through all this, but did this end up being successful mod?

I followed these instructions very closely and they worked great for my 3.4 996 motor swap. I did not use part #6 in the diagram...instead I used a long 10mm (40mm)bolt with a large washer. Been running it for two months and it works great!!

I should rephrase what I posted. Hard to tell by reading through all this, but did this end up being successful mod for a 3.2 engine? I've read stuff like car running too lean and MAF not working for the 3.2 engine. Also the images notech posted will not display for me.

Anyone confirm this working on a 3.2 engine? If so what did you have to do to make it work correctly. I have the month of February off and would like to do this mod if it works correctly.

What do you mean by work on a 3.2? The early 987s were 3.2 and the late run 550 is also a 3.2 and both used the 987 based airbox.

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Have you read this? It's a mess of MAF problems and the car running too lean.

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Reread if necessary! Additional post make it worse for everyone doing the right thing & searching for answers.

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I've read it several times trying to figure it out. Telling me to reread it is not the answer to my question. A stock 3.2 engine with this air box. There are people with MAF issues, AFR's concerns and if done does the car need a custom tune?

If we are looking at 986 S 3.2 you have two options with this airbox. 1. Saw the original MAF tube off the original airbox and plumb it ont the new airbox or Use a MAF tube for 987 airbox that can take the original MAF and 2. a) Remap the ECU with tune from a P-car with the same diameter MAF tube and the same type of computer (i.e. 996 from the same model year for the most part but you might want to research this further) or 2. b) get a remap from some tuner with good reputation that knows what he is doing. I myself have chosen to go with alternative 2 a) and got the so called rest of world tune from a 01 996 on my Box 01S. That way I got rid of the eternal CEL that I had for two years after catless performance header install. I first tried to move the downstream O2 sensors by lengthening the wires with thick wires to no avail, then tried so called O2 simulators but they did not work either. A good tuner would do the same but I like to be in some kind of control over what is in my car and also the original Porsche remap is much cheaper than a complete professional remap. And there is no question about it; these engines can use the improved breathing, but I think you should do both the intake and exhaust at the same time. Hope this helps.

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Excellent, thank you! Yes I intend on headers, cat delete pipes and Borla exhaust, but that will be late spring, early summer. Spent my current car fun funds on new bumpers, front, rear, body shop cost, new wheels, tires and a Euro Suspension Kit (ROW M030). I still have car fun funds to do the air box change out right now. The tune deal, can that be held off until I get the exhaust done?

Just go with Alternative 1. You will toast the engine if you run it for more than a few minutes with the big MAF tube as it will be runing in lean condition

Quotes source post: 433037

Is there a good benefit doing Alt 1? Would buying a high flow air cleaner be just as good? Like this one? Pipercross Air Filter Porsche Boxster 986 2 5L 2 7L 3 2L All Years | eBay EDIT: I can wait to do the air box change too, just have some free time (February off) and looking for something to do. .

I almost say "This has been beaten to death her". But I say this: It is a well known fact that Porsche choked the Boxster engine on purpose. Just do a search on that. A high flow air filter will help to open things up but will it do what it is supposed to do as well as the one it replaces? To filter the air and stop all small particles from entering the engine? Maybe if you use the type that you oil but then you get a lot of issues with the oil getting on the MAF and messing up every thing. So I will not have one of those on my car/engine as I am concerned that it gets proper clean air. The 987 air box has proper filter with much larger surface area than the original 986 filter and that is only one of the benefits. The piping is also more open, the box has bigger volume (and bigger MAF house as mentioned). And it is a proper "cold air intake" as opposed to some aftermarket intakes that claim to be, but in fact get some of the air from the hot engine bay. One thing that I failed to mention is that you should also do the 996 throttle body upgrade and 997 plenum at the same time as you do the 987 airbox and do something to open the exhaust. You don't want any weak links or bottle necks (as we say in my native language) in your stream of air through the engine. I think all these things work together and you only get full benefit from each, when you do them all. What you do to your exhaust depends on the state you live in, I am firm believer in performance headers, but they are down right criminal in some states, as known. And don't forget that exhaust can be tricky you can rob the engine of power with some expensive aftermarket systems. If you are not aware of this tread her about 997 plenum and 996 throttle body, I suggest you spend half a day of your life reading through it. You will enjoy it, it is fundamental and real interesting reading. And to answer your next question, my gussimate based on my 0-60 tests with an g-meter is that all these mods togeter give the S-engine about 30-35 extra horses. Worth it? I don't know. But it is dam fun process doing them all.

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From the other end, how far up is the screen located inside the 987 MAF housing? I missed the picture, and it answers my question.

Also can the intake manifold gaskets be reused or do I need to get new ones?

Well it depends.........they could or could not. I would believe they could, but you have to evaluate them after you open things up. It is not a yes or no question and not an yes or no answer

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Thanks, I'll order some in. I'm going to do your Option 1 for now. Got the complete air box assembly for $75 shipped. When I get ready to do the exhaust system, plenum and throttle body upgrade, it will be in there already. I have this planned out pretty good I think. Only thing that will be larger is the air box itself. So the car won't run lean, correct? Thanks for your help Bfan.

Quotes source post: 433295

Just for comparative purposes my old S was running a little lean with just stainless manifolds and a 2-box exhaust.

how could you tell - via the narrow band o2 signal to the ecu, or aftermarket wideband? if aftermarket, was the sensor placed before or after the cats? if using the afr from the ecu, did the ecu not correct the lean condition? also, at what rpm were you seeing a lean condition - part throttle, wot, or both?

Wideband exhaust lambda probe on the dyno.

if the probe is in the exhaust post-cats then I've read that it will read a bit lean compared to actual products of combustion pre-cats (which is where the ecu gathers its data from) so your actual afr might be where it is supposed to be. remember, regardless of what you have done to improve airflow (larger airbox, bigger plenum, bigger throttle body, better exhaust) the air still has to flow by the maf and be measured, and the computer just adds fuel based on the amount of air measured. so, as long as you are measuring air properly (ie, proper diameter maf housing) then things should be pretty much ok.

I understand what you are saying and have similar thoughts. However, that car had 5 or 6 dyno runs on the same dyno with different mods over a period of time and the car in the configuration above was the only one to show lean running. Of course, that doesn't neccessarily mean its correct! Ironically, after the fitment of the 996 throttle body the AFR was back to 'normal'. You could interpret it as a spurious reading or that it indeed was running lean as the other 5 or 6 runs all seemed ok.

that is odd. I understand that at low and medium rpms the 'tuning' aspect of the exhaust and intake come into play (ie, using restrictions in airflow to time pressure pulses with valve opening) but fuel trims should react and fix any of that. did the ecu have time to compensate between exhaust install and dyno? was the lean condition present throughout the rpm range, or just at max rpms?

Am very confused myself......

I can't remember all the details as this was back in 2012. I still have the printed dyno plots but can recall it was leaning out towards the top of the rev range, perhaps the last 1.5k. The mechanical fitting had been done some weeks previously so the car had plenty of run time in between.

ok. my understanding of ecu operation is that during normal driving (part throttle) it is in closed loop mode - the engine senses the amount of air in, looks it up in a table, and adds fuel as per the table. it tries to maintain the magic air:fuel ratio of 14.7:1 for best power and efficiency of combustion. the o2 sensors in the exhaust monitor the products of combustion and provide feedback to the ecu - this feedback allows the ecu to trim fuel levels in order to maintain an afr of 14.7:1. when the engine is working hard, ie in the higher rpm range, the ecu starts to worry about heating and detonation (the ecu can't control what kind of gas you put in, and can only modify timing a little bit). to address the issue it adds more fuel in an effort to cool the engine. this richens the afr to 12.5:1 or so. the o2 sensors only work in the 14.7:1 range, however, and can't provide any feedback to the ecu when operating outside of this value. as a result the ecu operates open loop and provides fuel based only on sensed air intake and fuel maps. my understanding is that, in open loop, it also ignores any fuel trim information compiled while operating closed loop. so, my next question to you would be if you recall actual afr values when you encountered the lean condition at high rpm. I ask as this may not be a bad thing. in fact, this is the standard trick used by ecu 'tuners': they can't change ecu performance during closed loop operation (any modifications to the fuel maps would just get trimmed out) nor would they want to because the engine is already at 14.7:1. instead, what they do is lean-out the fuel maps during open loop operation to get closer to 14:7:1 (ie, set the engine to run at 12.7:1 instead of 12.5:1). you lose the benefits of the additional fuel cooling the engine, but gain power (more efficient combustion) and efficiency (less fuel used). this is why they often require that only high octane gas gets used with their tunes. so, provided that the lean condition you encountered wasn't way out of whack, it wasn't necessarily a bad thing.

My 987 air box got here today. Been in talks with Rhonda at FVD about the Genius Flash Tool so I can fully utilize the larger MAF housing and get some extra power from the tune. I'll start hacking away at the air box to get it ready to fit into the Boxster. Car goes in the body shop Monday so I have some time to evaluate going the Genius Flash Tool route. Rhonda is supposed to get back with me after I send her pics of the parts so their engineers know exactly what I have. Side note: If you're a forum member at 6speedonline FVD will give you a 10% discount on the Genius Flash Tool.

While cleaning my MAF sensor today I noticed some hoses going into the air tube from the MAF housing. It's related to my Tiptronic transmission. I circled them in red and they both go into the air tube. Throttle Body Thoughts on how to deal with this?

Can't tell you how much it helps to have the Plastic Soldering Iron while doing this. Thanks for the heads up on that TRK! I bought a used Porsche tow hook cover, trimmed up the inside a bit so the inside would fit into the hole and used the soldering iron to melt it to the hole in the air box, sanded and looks great! Originally bought the tow hook cover for the bumper I was going to have installed. That didn't work out, but to cover got used. One like this, but I got it for much less. http://www.ebay.com/itm/Porsche-911-505-703-00-front-bumper-cover-tow-hook-cover-cover-eye-/121503674097?pt=Motors_Car_Truck_Parts_Accessories&hash=item1c4a2eeef1&vxp=mtr

I just used a piece of plastic I cut from the air box and RTV-ed (hot temp.) it to the air box. It works great and I do not have to worry about vibration or heat. I was concerned about the plastic welding and its potential strength. You will have to use a long 40mm bolt and finder washer to hold the air box from the inside.....or at least I had to.

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Which bolt number are you referring to?

The bolt goes through the hole that #10 and #6 previously used. The fender washer is large enough to cover the larg hole and hold everything against the inner fender side wall. When you tighten the bolt it pull the air box to the side wall helping point #2 down towards the ground making it harder for water to get in. Good luck !!

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That's a great idea. I've order #6 and #10 from 3 different places. 1st place canceled the order, said they couldn't get the part, 2nd place said it will be back ordered up to 30 days to get the part, called a dealership and they said it's a Germany only part 6 weeks to get it. I placed an order with ECS Tunning, says it with ship in 6 days. If ECS Tunning says back order, I'm going the bolt route.

I keep Torque App constantly connected to ECU for real time reading. Unfortunately I haven't saved my logs before the airbox and throttle body swap. Is anyone running it? I'm particularly interested in your stock max MAF cfp values / O2 values. thanks

One more question, during the airbox swap, mechanic used a different boot to connect the manifold, he put one with no hole, therefore that little tubing is not connected anymore. Anyone knows what is that for? Can I drive without reconnecting it? any harm? much appreciated

That little hose connects to the fuel pressure regulator. It adjusts fuel pressure relative to manifold vacuum (throttle opening). You're gonna need it.

How does the 987 air box intake sound compared to 986 (desnorkled) once installed? Is there a difference, what does it sound like? Thanks in advance for any input.

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Never desnorkeled my 986 box. The 987 box and intake upgrade that I have done, she gives a good roar at WOT with the snorkel on. I would imagine it's more then what a desnorkeled 986 box gives. You can tell the 987 box is moving some serious air.

Is there a difference between a 986 throttle body and a 987? I am switching my 986 cold air intake box to a 987 (as Brad suggested) and the Intake "T".. surfing flee bay it seems they have part number of 98660511501, or 99610702600 regardless if it is listed as 986 or 987!?

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I highly recommend going to a 987S throttle body, 10mm bigger I believe. After I installed this on my 986S, it made all the difference along with the 997 T. Similar to what Pedro sells I'm told. And the intake roar is probably the most enjoyable part of it all!

Ditto on this mod. It transformed the car. Now looking for Lt weight Crank pulley to compliment it. Do it! Toughest part is getting 987 intake in, then downhill. No regrets!

Put the 987 snorkel on it. Much smoother hp and torque curves with it.

Take the intake manifold off on the drivers side. It is easy to remove and will save you countless hours and stress.

I just picked up the parts to convert my '03 S to the 987 airbox. I was able to find an airbox with MAf housing and rubber connection hose, which would mate with a 987 throttle body T. The interesting thing is that from the pictures that I have seen the '04 550 edition looks to use a different throttle body to MAF hose to match the 987 MAF housing to the 986 throttle body, but I don't see it listed anywhere. Odd. I also found the split intake T from an '05 987 S with the vacuum flap and PCV hose. With these parts I THINK I will be able to bolt everything in using all factory parts. I haven't yet checked the vacuum control diagrams to see if the vacuum valve was control separately from the other intake flap. Has anyone tried the either the early or later 3.4L 987 throttle body T on a 986? It does move the throttle body down and back closer to the MAF housing. Hopefully this won't have clearance issues on the 986.

it was discussed in the other intake thread i think and, if i recall correctly, the flapper on the plenum is mapped differently than the one on the resonance tube.

I pretty much assumed that was the case, but I can't find the where in the intake threads that this was discussed. I guess I need to have a look in the 987 diagrams to see how it was set up. I have a feeling that even if the late 986 M96.24 and 987 M96.26 are almost identical and use the same ECU hardware, the later 987 software may not work in the 986. I may have to go play with a local shop PIWIS II to see... I haven't seen any posts where someone with a '03 or '04 adapted the 987 air box. I would like to see if they found the 550 edition MAF to throttle body hose.

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In the UK at least the 987 has a different AOS arrangement with an extra clip. Why would you need the 550 MAF to TB tube? If you upsize the TB it won't be of any use anyway.

....so I have a 986 with a 987 airbox from the factory. If you need photos let me know.

You will have to let us know how you make out. BTW haven't forgotten I still owe you $$ for my gauges!

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For those interested in upgrading the "T", the Thread linked may be useful& cheaper than the plan mentioned in the quotes: http://986forum.com/forums/diy-project-guides/55966-intake-plenum-911-throttle-body.html

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I would like to see that, especially the throttle/body area

The throttle body area part itself look very similar to a regular 986. What you do have is a more solid plastic MAF to TB pipe with a smoother curve. From memory the neck of then plenum is the same length as the regular one too. The MAF is also further ER away from the airbox almost next to the TB.

All of the parts arrived yesterday and today. I have the 987 airbox with snorkel, 987 MAF housing, rubber hose from MAF to throttle body, and 987 "split" T that the throttle body mounts to and the matching hose to AOS that goes to the ports on either side of the T. I went over to a shop today on a break from shopping and mocked it up on 986 engine and everything looks like it will mount right up. The only question is what to do with the vacuum controlled flap in the T. I did find a picture of a stock 550 edition '04 engine compartment a few days ago (a UK site maybe?), but I can't find it again. As we all know, it uses the 987 airbox, but with the 986 throttle to intake T. There is no different part listed for the throttle body to MAF hose, but it is obviously different than both the "normal' 986 and 987 parts. I have seen it before where Porsche will have parts on cars without showing the part numbers in the parts breakdowns. So, I would like to see the actual 986 550 throttle body to MAF housing hose and its part number if possible. I did also noticed that in the parts diagram they have a part 98711026000 listed as "Stopper" that is not in the diagram, but goes with the 550 edition in the Throttle Body diagrams, which is not used on other cars. I would be interesting to see what that is as well.

Here's the 550 Anniversary arrangement

so, a quick look at the parts diagrams shows a 987 part number for the duct on the SE car - 987.110.22 0 .01. a check of the 987 boxster (not cayman - it uses a larger TB for the 3.4) parts diagrams shows that the intake duct is 987.110.22 2 .01 - different part number. so, that first part number is what you would need to join a 987 airbox to a 986S 67mm TB and plenum.

...is there a specific 550 se MAF housing or is it just the larger diameter 987 piece ? What diameter is it? It needs to be the right size for your tune.

From memory the 550 uses the same MAF as regular 986.

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How would that work, since the 550 uses the 987 airbox? My reading of the parts KATALOG indicates that the 550 uses MAF with part number 987-606-125-00...

and the 987 maf comes w the housing, unlike the 986 part. to Q, you have a 2003 so 7.8 dme. you want a flash for a car w the larger maf holder and the improved variocam (but not variocam +). you are limited to the se flash or *perhaps* a 987 boxster flash. 987 boxster would be excellent as it would have the programming to drive your new flapper, however i am uncertain if it would work well on a 986 car - i *think* the 987s have other programming built in to the dme such as traction control; it may not function properly as all systems are not connected (i've asked this question before on several forums and never got an answer). otherwise, i had done some research previously that had indicated that the plenum flapper was controlled differently than the resonance valve (worst case, check the wiring diagrams for the 987 - seperate wires for each would indicate different control - or get someone with a 987 to have a look). you could delete it altogether, or use a solenoid triggered by the same signal as the resonance flapper, or use an rpm signal to trigger (if you new how it was supposed to function, you could build an rpm-triggered window siwtch to actuate it).

Good information! I knew that the MAF to throttle body hose needed to be different. Thanks EDC for the picture confirming that, and thanks to The Radium King for the part number. I must be looking in the wrong place, as I could not find a different number for that part. Now a harder question concerning the 550 edition, that won't be so easy to verify. Did the factory modify the airbox to remove the resonance chamber, or did they modify the chassis (I kind of doubt that)? Also, for those who have fit the airbox, are the mounting points identical? That is, do you just bolt it in with the existing hardware, our do you need to modify or add things like bolts or washers? Personally, I am not sold on the bigger throttle bodies until I see dyno data, not just "butt dyno" impressions. From experience, bigger throttle bodies need to be mapped properly to match the flow characteristics. Just bolting a larger one in and running it can lead to odd part throttle behavior. That probably wouldn't show up on the dyno, but would be felt in real world driving. I am not a fan of something that might give me 5 hp on the top end at the expense of drivability.

Just my personal experience, the 987 airbox mounts to the original location. At least 3 and yes you will loose the Hemholz chamber the 986 had as there is no space. Impressions to me driving it is that I lost a bit of low end just around 2.5-3.5k rpms but by 4k you are really booking and linear all the way. Just a bit of trade off but that push from 4K is really nice and looking back with the smaller TB it just felt slower between 4K and redline. By Butt Dyno it really feels like there's more than the numbers suggest.

Not that I am good at stopping and testing, but we could just go back to a standard stretch of road and stop watch or timing / dyno software to gauge performance changes.

I've posted dyno data before of mods on my first Boxster. Base line, exhaust and manifolds then throttle body and intake, then lastly remap. All on the same dyno.

link, please?

http://986forum.com/forums/performance-technical-chat/47555-tuned-modified-2000-boxster-s.html

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Very nice thank you....would like a visual on your exhaust components

It's the regular cheap eBay stuff. It's all from alibaba ultimately. Over here it's branded as Toyosport, Topgear, Direnza etc as they place large enough orders to have their label put on or stamped on. Over your side I think this is the same as Topspeed but also resold as various other "brands". Remember only 1 pair of cats for UK and European cars ie no cats in headers. I kept the standard cats which are 400 cell. You call them the rear cats.

So, I ordered up the '04 Boxster S 550 50th Anniversary SE MAF sensor to throttle body hose, along with the "stopper" that was listed, but not shown in the diagram. The stopper was over $25 and just ended up being a plug for an unused port on the hose. IMO, it is NOT worth it if you want to do the same. Here are a couple of pictures. In the first I have the 987 airbox, the 987 MAF sensor and 986 SE MAF sensor to throttle body hose. In the second picture I also included the 987 throttle body tee, 987 MAF sensor to tee hose, and tee to AOS tube for comparison. As you can see, I have not yet modified the airbox to fit in the 986 chassis. While it is possible to use the 987 tee, from testing by another local shop shows that it difficult to install due to interference of the throttle body to oil cooler if clocked as on the 987, and also interference with the engine cover if you clock the throttle body so it does not hit the oil cooler. The tee also does not play nicely with the tuning if you actually connect up the vacuum operated flapper, so you would probably just use the tee without hooking up the flapper. I plan on installing the airbox with the 986 SE plumbing after doing a baseline dyno test, then repeating the dyno testing after installing the airbox, plumbing and 986 SE tuning. The tuning will only work on an '03 or '04 S as they have the M 7.8 ECU. It is also possible to use these parts on earlier cars with stock (or whatever performance tune you have) if you sleeve the inside of the MAF housing to match the original, and use the MAF element from the original air box.

You need either the 996 plenum or the larger one from Cayman 3.4 if you want to go to the 74mm throttle body at the same time.

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Qmulus, do you have the part number for the SE Maf to throttle body hose? I am having a hard time finding it and I like the OEM look and may look at using it in my install.

You can find the part number in post 269 by The Radium King, or is it pretty easy to find in the online parts breakdowns. The part number for the "Stopper" is also in one of the later posts by me, but I wouldn't bother getting it. I am sure that you could find something that would fit that is far cheaper than the expensive factory plug.

Finished my 986 to 987 airbox and 3.4 throttle body & plenum upgrade. Here's a ton of pics and a write up including part numbers. My car is a 2003 Base Tiptronic but this should work for all 986 models. USE AT YOUR OWN RISK!!!!! NO NEED TO BEND CLIPS OR TAKE APART TOP OF ENGINE - Easy to do if you have access to a lift & engine jack... USE AT YOUR OWN RISK!!!!!USE AT YOUR OWN RISK!!!!!USE AT YOUR OWN RISK!!!!!USE AT YOUR OWN RISK!!!!!USE AT YOUR OWN RISK!!!!!USE AT YOUR OWN RISK!!!!!

USE AT YOUR OWN RISK!!! USE AT YTOUR OWN RISK!

Use at your own risk! Use at your own risk!

Use at your own risk! Use at your own risk!

Hi, looks like the front engine mount bolts are still on and thus the mount is used as the pivot point. Where do you place the jack to lower the assembly? The differential in the transmission?

Used an engine jack with a wood board to give as much support as possibly to the whole assembly. Only really needed to lower it a couple of inches. PS: If I didn't post it before - be sure to check the wheel alignment when done with this project.

Great post, I didn't see how you will reprogram your bigger MAF sensor housing?

Nice technique!! Were there any precursors to this sequence? Other items to unbolt prior to starting. I am surprised that the whole assembly can pivot on the front mount and not interfere with the studs

Great info, I will put in the 987-box this winter.. However I´m also about to change the front engine mount. Do you think that the same trick (lowering the engine to switch airbox) can be done by lowering the engine in the front while the front engine mount is removed during the switch? I know, I need to get off my computer and get going in the garage..

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Fabspeed will be doing the reprogramming in the spring.

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They write up was pretty much it. A-Z. Definitely needed to get a wheel alignment after

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You can probably do that but then you really need to secure the engine and trans. Why not do the method I used and change the front mount after you put it all back together? Changing the front mount then makes more sense I think.

Has anyone done this to a 2002 Boxster S? I have a question about the tune used.

For all those who wants to use the 987 MAF housing on the 986 S ... I have used this reducer which fits after a bit sandpaper exactly in the 987 MAF housing cutting out a hole for the MAF https://www.pvc-welt.de/PVC-U-Klebemuffe-ECO AL107

For all those who wants to use the 987 MAF in the 986 you can just implement this into the MAF housing to reduce it safely AL107 https://www.pvc-welt.de/PVC-U-Klebemuffe-ECO

I would also like to confirm the tune for a 2002 S: the 7.2 DME will work with the 996 tune?

So I was able to add the 987 Airbox, 987 MAF Tube, 997 Throttle Body, and T-Plenum in. All parts were slightly used, but looked decent. Fired her up. Drove her around for a tad, and now I have 3 codes. P1119, p1126, & p1133. I need a tune which should happen this week. Is it possible I need a new Throttle position sensor? Or should I try to do the throttle relearn procedure first?

For anyone looking for a 987 MAF housing adapter sleeve (3.25" OD 3" ID) I found this on eBay that might help. The pvc-welt link wont work for us US folks ( AFAIK ). https://www.ebay.com/itm/16mm-200mm-PVC-Inner-Diam-Equal-Water-Supply-Pipe-Fittings-Adapter-Connector-/174808609002 Hope this helps someone. Im in the process of sorting parts for this upgrade now.

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You don't need a new throttle position sensor, what you need is a tune with a updated MAF-table to reflect the larger MAF tube area.

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Hey robert! speaking of tunes, how is your car doing? Any updates?

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Hey Ike, thanks for asking! Car runs really great, just wish the summer was longer! Next mod will be coilovers I guess.. 😎

That's great to hear man! Coilovers are phenomenal. My car has less than 40k when I switched over, and the OEM struts were toast. The coilovers made a truly remarkable difference in handling characteristics. Sent from my SM-G970U1 using Tapatalk

Btw, as stated previously I put in the 987 airbox & MAF with great results.. My tuner made a new MAF-table so if anyone needs a MAF table for the 987 MAF with Motronic 7.8 let me know!

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Initially, looking for a non-tune solution. Does the 987 assembly come with a MAF sensor installed? I think that is what I understand. I assume the 987 MAF and fitting comes off (with the special security bits) and the PVC sleeve slides in to reduce the ID to 3". A hole is needed in the reducer tube, and the 987 MAF and fitting is reinstalled? Assuming the 987 MAF assembly comes with a MAF installed, the connector plugs right in? Later, I assume I can remove the reducer and push a 986SE tune on a 2003 986 S?

One done also here Used the best from from two posts: http://986forum.com/forums/335445-post196.html from The Radium King and http://986forum.com/forums/605375-post286.html from scottmaggie We have started according to the instruction in The Radium King's post, but we didn't bend the engine lid tab. Rather we lower the engine a little bit according to the instructions from scottmaggie. But again 6" or 15 cm is impossible to lower, the hoses start to "dislike" it after 3" or 8 cm. We unscrewed only 4 bolts in the front mount of the engine. It was enough for me. I can't imagine to insert the 987 air box there with the left air distributor still mounted. Don't forget you need longer bolt as mentioned in step 17 in scottmaggie's instruction, and also insert the blue rubber grommet from 986 air box instead of the 987 black plastic grommet for tucker before trying to fit the air box. We were able to fit the Air Mass Flow tube when the air box had been bolted. No need to mount it on the air box in advance. The K&N filter was also little pain to fit. The rest slightly differ to the other posts here since I was fitting GT3 throttle body not the 987 one. The T-shaped intake plenum and the elbow part was 3D printed. Designed by Ben006. More info here: http://986forum.com/forums/diy-project-guides/55966-intake-plenum-911-throttle-body.html After all mounted and 3 times checked all is connected back, I turned key to position ON for approx. 1 minute. Then OFF for another minute. Then with fingers crossed we started the engine. The engine was able to idle without engine light and any fault code in the ECU. Strange... The AF ratio was definitely too high because the engine was "shooting" to the exhaust. Unfortunately our multibrand diagnostic tool was not able to start the basic adjustment of the ECU and engine components. ECU started to learn at the third start when I didn't let the engine idle but rev it just under 2000 rpm. After 5 minutes there was standing perfectly idling Porsche Boxster S 986 with 987 Air box with K&N filter, 987 AMF, silicone hump hose, custom 3D printed elbow, short silicone hose, GT3 Throttle body, custom 3D printed intake plenum, OEM air distributors and OEM 3,2l engine . In addition long exhaust manifolds, OEM CATs, and sport mufflers. At that time without engine light or any fault code in the ECU. All took 12 hours. Everything in the engine bay is super tight, nearly no room for hands and tools. Many times we got stuck because the hose refused to connect back or were finding from which spot and which kind of wrench from wchich direction to use to screw some of the bolts. BUT Engine light came up after ca. 50 miles / 70 km on my way to tuning company. No limb mode just orange engine light. Unfortunately they were not able to dyno the car because even switched off PSM the car refused to rev over 4000 rpm without massive loss of power. Need to find someone with 4x4 dyno which can rotate also front wheels during measuring. So confused I forget to ask what fault was there. They just done small adjustment to "fix" this error. No special tune so far... Anyway looking for any Porsche specific diagnostic tool because readiness for emission test is still not green. So I don't believe to these multibrand diagnostic tools anymore. Because they probably show only emission relevant DTC not all of them.

Reviving this thread, if it's OK with members.. I am going to start doing this upgrade with my 2000 Boxster 986S.. So far I have the following: 1) 987.1 Airbox with the MAF section 2) 74mm TB from the 997 3) Plenum from the same 997 Still a bit confused if I either need to use the 987 MAF or the 986 MAF along with these upgrades? If I go with the current 986MAF, do I need to have it tuned? When do I need to have it tuned? if so, what's the best way to do this? My apologies if this has been covered already... I read through all 16 pages, but still a few questions left.. TIA, Regards CB

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is up to you. first, some nomenclature. the maf is the sensor. the 986 maf is the same as the 987 maf. the maf housing is the tube the maf mounts to. on the 986 it is part of the airbox. on the 987 it is a separate tube that attaches to the airbox. the 986 maf housing is a smaller diameter than the 987 maf housing. the computer multiplies the maf reading by the cross-sectional area of the tube to determine flow. so, change the tube diameter and confuse the computer. if you do not wish to do a flash then saw the maf housing off of your 986 airbox and plumb it all together. the 987 maf housing is not required. otherwise, if you plumb it all together using the 987 maf housing then you need a flash that will work with this larger diameter. for a 2000 the solution is a 996 flash. the 996 of the same year had the larger intake tract and the 3.2 runs just fine with this flash. your dealer should be able to provide for you, or anyone with a piwis or pst2 contraption. the benefits of the latter option are twofold; using the larger diameter maf housing removes a restriction to airflow. second, the thinking is that porsche neutered the boxster so as to not compete with the 996. otherwise a 3.2 should not be 50 hp down on a 3.4. there's only 3 places that can happen - exhaust, intake, ecu (fuelling, timing). so, an ebay exhaust, clean up the intake as much as you can (pro tip - bolt an intake manifold from a 3.4 onto your car) and 996 tune.

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Thank you so much for the valuable information. You are right about getting my nomenclature right... Usually picture a MAF as a pipe/sensor included as in my older bimmers... DIdn't know the MAF are was part of the 986 airbox. Couple of questions please(actually 3 ) : 1) Any 996 tune will do it? I am sure there's a difference between the base and the S version. 2) I have the 997 TB/plenum (in combination with the 987 airbox). Do I need the 996 intake as well? Is that a must or a nice to have? Was planning on keeping the 3.2S intake intact. 3) Suggestion for the pipes/bends to connect from the airbox to the plenum? Already got the exhaust, and downpipes (no secondary cats)... but keeping the stock headers/manifold due to the emissions regulations in my county. Was planning on leaving my car stock (wishful thinking lol)... but I can never manage to do that with my cars. Once again, thank you so much for your help and feedback. Regards CB

Thank you so much for the valuable information. You are right about getting my nomenclature right... Usually picture a MAF as a pipe/sensor included as in my older bimmers... DIdn't know the MAF are was part of the 986 airbox. Couple of questions please(actually 3 ) : 1) Any 996 tune will do it? I am sure there's a difference between the base and the S version. 2) I have the 997 TB/plenum (in combination with the 987 airbox). Do I need the 996 intake as well? Is that a must or a nice to have? Was planning on keeping the 3.2S intake intact. 3) Suggestion for the pipes/bends to connect from the airbox to the plenum? Already got the exhaust, and downpipes (no secondary cats)... but keeping the stock headers/manifold due to the emissions regulations in my county. Was planning on leaving my car stock (wishful thinking lol)... but I can never manage to do that with my cars. Once again, thank you so much for your help and feedback. Regards CB

not sure if there was an 's' version of the 996 (at least in 2000 anyways). regardless, all 996 used the same tune. the 997 (or 996) intake plenum (the 'tee') will fit on the boxster 3.2 intake. it is the same width but a slightly larger diameter - i was able to stretch the rubber boots to fit no problem. what bends, etc. you use would depend on whether you are using the 986 or the 987 maf housing. if you are going with the 986 unit i've got the assembly off my car i could probably part with (ie, when i did the airbox and tb/plenum but hadn't done the tune yet).

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Thank you. Do you mind if I send you a PM? Regards, CB

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Hi Did you eventually go with the 987 maf tube and tune? If so did you see a performance hp gain over the 986 maf tube? Thank you

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i did install the 987 maf tube and push a 996 tune onto the car. it sure felt like performance improved not nothing quantifiable. my thought exercise was that the hp difference between a 3.2 and a 3.4 was too large to be just due to displacement. intake, exhaust, and tune are the only other variables as the heads and bottom ends are the same. so, i improved intake and exhaust and put a 996 tune on it. all the porsche rats at the track think i am running a 3.4 and i can chase 987 spyders around pretty easy.

Thank you for the reply. I have looked at the 987 airbox and before the maf but after the filter there is a 90 degree turn that constricts air flow to less than the 83mm id of the 987 maf tube. Difficult to judge exactly what it is due to its angle and turn but I would suggest around 70mm. With the above in mind what is the point of the larger 987 maf tube over the 986 maf tube? All that is happening is that the restriction is moved closer to the air filter. Any thoughts/comments?

every time you compress air (force it through a narrow opening) you do work. and heat the air. i would rather do less work and have cooler air. but make your own choices. to quote yoda - do or not do.

So the MAF tube from a BMW 540i has been recommended in this thread as a good choice when installing a 987 airbox but can anyone tell me the diameter of that MAF housing? Is it the same as the OE 986 tube built into the 986 airbox? I'm trying to make sure it will work with the 00 986S ECU and 996 74mm throttle body without going lean. The MAF I'm referring to is Bosch #0280217814 from a '00 BMW 540i among others. There's a lot of good info in this thread but much is outdated and/or confusing; I'm going to start a more current thread and am in the process of determining the best info to put in that thread. My goal is to list the parts at the best current prices and availability to help anyone trying to complete the 987 airbox mod. I'll post a link once the new thread is created. Thanks to all who have created this thread and would love to hear any updates they may have regarding their experience since some of these posts date back to 2012!

I did this with my project S. I used the 987 MAF sensor but neither elbow would work so I had to make one using a silicone elbow. I was also advised to get a 996 ROW tune since I added headers (stock is beyond abysmal, might as well be a Model A!) and block-off plates for secondary air injection. I never got to try it as engine 2 locked up a mile from the shop helping sort it. Building engine #3 now so hoping to see how this works later this summer!

"Is it the same as the OE 986 tube built into the 986 airbox?" no

I just bought a 3.2l M96.21 to replace my blown 2.5l I will upgrade the intake before I install it in the car. I'm planning to use the 996 3.4 TB, with the 987 airbox and MAF tube. I will restrict the tube dia down to match the 986 tube. I will be installing headers and exhaust later. There are no Porsche tuners in this country that I know of, so I'm going to ship the DME abroad for the flashing. Considering I have the 2.5l tune now I guess a flash to a 996 tune will be a requirement. Is there anything specific that should be done to the tune while they are at it, or can I rely on the stock 996 tune to adapt properly?

“Considering I have the 2.5l tune now I guess a flash to a 996 tune will be a requirement. Is there anything specific that should be done to the tune while they are at it, or can I rely on the stock 996 tune to adapt properly?“ The guy who helped me assemble the bottom end on my 3.2 worked for and has a shop close to one of the big Porsche parts operations. He has a 996 with a big bore kit that runs great. I asked if he tuned it. He said the ECU adapts just fine, so, no you should be ok by that metric.

That sounds promising, but it seems to counter what others say in here. Perhaps it's one of those things that varies from setup to setup.