Anyone running eGas ported throttle body here?

Just want people to chime in that actually has one. I've only seen non-eGas versions for regular c2 models.

may be you can explain what is 'eGas' and 'ported throttle'

E gas means electronic throttle or any C4 or later 2000 car. The throttle body can be ported larger, but the intake T tube would be restricted. IPD make larger intake tubes that fits GT3 throttle body and claim HP increase. My reservations are that the factory never increased the size of the throttle body on neither the 3.4 or 3.6 engine. I have to guess while it might gain a few top end hp some of the lower end hp suffered. IMO it is a questionable gain and i would need to see more independent testing to think it would be worth it.

JRGordon has done this mod and has dyno'd it with positive results hence the reason why I'm willing to tackle this. His is a non-eGas. I'm not sure if I'll be the first but I'll take one for the team. BTW, I wouldn't be totally disappointed if it didn't actually give me any HP as long as throttle response was improved. Yes I currently have IPD plenum which can be bored out further as there is enough material there. Also, the factory never increased it so they can charge you $25k for the x-51 package. LOL

For the non-egas: http://www.fvd.de/us/en/Porsche-0/99...NON_E-GAS.html

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Link doesn't seem to be working but I went on the FVD site before and didn't find any throttle body for eGas 3.4 Carrera model. I've only seen non-Egas for 3.4 996 and another for 996 GT3 models.

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Does the X51 have a larger TB? My understanding it is same size as regular TB just the hose is slightly different.

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larger tb and different intake manifold and plenum.

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Agree. I did not see any for the egas either. Send them an email. Maybe they have something available.

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I plan on doing something custom locally.

It does make a significant difference even though the cable TB is only 1.8 mm larger. If you really want to rock-n-roll use a early GT3 TB. I believe Viking used one a 3.6 race car.....

I am surprised this topic never came off before. so many discussion about the IPD plenum, but not mch about the Throttle Body. I'd be curious to see a documented mod

good timing on this topic! I was just thinking last week that since I have added the IPD plenum a few years ago to already installed headers and 200 cel cats and EVO CAI that adding a larger bore throttle body might make some sense. So I have ordered the unit from FVD and will install it before taking the car out of hibernation. I'll chime back on this subject after driving around with it for a few weeks. Pete

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Waiting for impressions on this change...

My cars a non egas. I have had the IPD plenum for a while now and just took out the IPD plenum plus the TB. TB is being shipped tomorrow to get ported. The guy only does TB porting and charges 99 shipped.(vs fvd 450). 1 day turn around and he inspects/cleans/disassembles and makes a new butteryfly/ports to the max. Stock TB is 76.4mm and goal is 2mm(again fvd 1.8mm). While I'm waiting, I just got done hand porting the IPD to 79mm(IPD came stock just about 77mm). He does port egas TB's also. I should have the TB back in the car this saturday, I'll post when installed.

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You mean stock TB is 74.6mm? IIRC, my IPD was the same diameter as the stock TB opening. Pics of the ported IPD? Also, I'm assuming you're going through Maxbore porting services which I also plan on using. FWIW, they've been in business for years and have ported a few of my TB's over the years. Never had any issues yet.

The stock non egas TB intake side is 74.6mm. TB manifold side opening is 77.5mm. My IPD was 77mm. I used a dremel and opened it up to 79mm removing some of the orange coating that IPD has on the inside. Yes, maxbore will be doing the porting.

I'm going to see how wide maxbore is going to go on the TB manifold side. I might have to port the IPD a little more but I'm getting close to the gasket.

Thanks for the clarification. Yeah I'm also wondering how close I should get to the gasket.

Sorry for the crappy pic. I'll post more after i get my TB back and see if I need to port more.

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Yes, I have used much larger GT3 TB's. The hp was minimal but did help, it did also move the tq curve a little, but the main thing to remember is that I did this on a non street car with multiple other mods. So your results on a street car will be different. An engine is really simple, it's an air pump, more air in while more air out, makes more power. Just more air in, will not necessarily mean more power. Many times it may make less power, this is why some see no gain with IPD. The key is knowing the weaknesses in where the restriction is and then modifying that to flow more air. Stock they are pretty matched up well, I think Porsche may have spent some money in the R&D dept. Now if you've added headers,no cats,open exhaust, flowed your heads, or up'd displacement, by all means, add the TB, it will probably help. Both JR and I run some bastard combos for the race cars, it works for us in our specific applications but neither of us JUST have a TB alone.

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Do you know if the mounting holes for the GT3 TB line up with the stock C2 plenum? I've thought about going that route but the only thing holding me back was the mounting issue.

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No, you will also need to change the "T", as well as deal with the larger hose to the airbox, as well as possibly a vacuum line difference depending on year/ model. The easy way would be to get the "Race or Comp IPD" pleanum which makes it a bolt on. But then you are changing too many parts to know which one will be what gains you or losses you any power. Also keep in mind that porting your stock one does really change the flow a lot, be careful here.

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Thanks for the clarification. And yes, one of the reasons I want to stay with the stock is the minimal increase of around 2mm should be more compatible and less overkill than a gt3 setup, especially without having any kind of cams and headwork.

Anyone who wants a New IPD plenum for an e-gas car PM me. I will throw in an e-gas pedal for anyone thinking of doing a swap.

So, I got my TB back. FVD advertises as stock TB 74.6mm and enlarges to 76.4mm(1.8 increase). I have a feeling this is measured at the intake side opening? My TB was measured at the narrowest point, the butterfly area. Stock measured 73.5mm. The butterfly was increased to 76.4mm(2.9 increase). The intake side opening size is right at 76.4 or .1 or .2 larger. I wasn't able to drive around much as moderate rain where I'm at but observing 70-80% throttle up to 5k rpm's, throttle response is definitely noticeable. I'll report more after the weather clears up.

Great to hear but my measurement came to 74.6(eGas) at the butterfly opening, however I did notice yours was non-eGas. It would be interesting to see the effects after adaptation values have changed over time. Any pics of the modified TB? Did they use the same material as OEM for new butterfly plate? Unfortunately, I have to wait until George returns from vacation to do mine.

Maybe egas difference? George's measurement was 73.5(I didn't measure butterfly before sending out). Sorry, I didn't get to take any pictures. I was busy reinstalling the IPD(such a PITA). The IPD was open up slightly larger than the TB manifold side. Also, cleaned up all the oil on the IPD and replacing the coupler hoses. I'm not sure on the butterfly material.

Let us know your air fuel ratios with the modified throttle body. Some say lean conditions are possible in the upper r band Best is to throw it on a dyno once you've had a chance to drive it around and do a few pulls to make sure your not running dangerously lean.

Until we make serious internal mods we see very small gains from adding larger plenums/ throttle bodies and etc with these engines. In my experience those things generally create more negatives than positives. I start to worry about optimizing this when my 3.4 based engines are taken to my Gen3, 3.8 specs, or a 3.6/ 3.8 based up to a 4.0. At this level things start to make enough of a difference to tweak the induction, below this point I simply don't see the returns from the modifications being great enough.. Opinions will differ. Results will vary.

so if somebody added a larger TB to a 3.4 that has the IPD Plenum, 100 cell cats, exhaust and K&N air flow filter with an ECU flash how much extra hp would you gain? ballpark...?

25-30hp at the wheels would be my guess....I think i've done everything NA without opening up the motor and I'd be happy with a 30hp gain at the wheels with all the below. intake/TB/IPD/pulley/headers/200cell/straight through cans/GIAC tune The only thing I'm going to do at this point is switch headers. I have a 44.5mm piping "equal length" headers but I'm going to switch to x51 style log headers just due to the fact that they are 48mm piping. Sure, I would have gained 100hp+ with a supercharger with the same amount I put in but I'm still happy...for now

Sorry I misread what you wrote. I thought you were asking if all of those mods were done. I don't think anyone has dynoed just adding a TB to your mod list...

Never noted anything like that from an induction change here on my dynojet chassis dyno. Making that much real power is quite a chore, its not like its made out to be in those shiny magazine ads, here in the real world.

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Sorry I meant with all the mods I listed above...

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I tend to agree for the most part and I am not really expecting much. If the engine design is maximized for performance from the factory with little room left on the table for improvements, short of making the engine pump more air through high lift cams and doing headwork, the rest of the intake tract will generally yield minimal improvements. With that said, I haven't seen too many actual dynos with these mods other than from the manufacturers or resellers. Lots of talk but nothing to back them up. I consider this somewhat of a costly excercise but something I want to do to satisfy my own curiosity. I would love to dyno after every mod but not too practical due to cost. I do plan on getting it on the dyno at the end of my journey to see if it was worth it for me.

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Jake, what kind of -ves do you see with a bigger TP here...? I heard it's only good for 10 hp and 7 lb/ft of torque... probably not even worth it on a 3.4

Porsche X51 = lots of mods and lots of money for a modest 25hp so I always have a tough time buying into the numbers I see advertised for go fast add-ons :/

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All I've seen is the power band move and not enough of a change to warrant the time or effort. Its pretty easy to end up with big intake syndrome on OEM engines that are smaller displacement. BTW_ I have a total of three dynos, two of which are engine dynos and one of those is the only M96 engine dyno in North America, but none of them are smarter than we are. The dyno is just a tool, but it doesn't trump old fashioned evaluation and here I use both and let the engine tell me what it likes. This mindset isn't found with today's "Tuners". Hell, my Wife set 4 Land Speed records after I made a change that LOST 6HP at the rear wheels but made for a much faster engine. Prior to that the engine was impressive on the dyno, but was .5MPH away from several records, after the change I went with my gut and those records still stand today. When we start "racing dynos" things will change. Where the engine makes its power is the key.

I've put a few hundred miles after TB as of today. Throttle response definitely improved. This is lower and upper rpms. Revs easier. I'm not sure how to interpret this data but all pulls from 2nd gear full throttle to letting off middle of 4th gear before max timing advance 49 after max timing advance 49(as expected) before max MAF 258g/s after max MAF 238g/s.

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I agree. I care more about the area under the curve for a street driven vehicle more so than peak hp. People always talk about peak hp but seem to rarely concentrate in the areas that count. Your $&@& might be longer but I have more girth. LOL

agreed.... lol cams is probably your only way to get some good torque under the curve and FVD makes some good ones... but don't know if it's worth the time or $$ to install them for what you get... pretty pricey but will work well with all the other mods....

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x51 actually produces 40hp... 25 hp is just porsche's conservative rating

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Can you site source for the 40hp boost on x51? My 2004 40th AE w/x51 = 345hp as per Porsche. You claim 40hp which would make it 365hp yet a GT3 of same year 360hp. I have been in a 2004 and a 2005 GT3 and they are bothe heck of a lot faster than my 40th AE. So....

Ask around. That is the whisper number at Porsche. X51 is around 363 hp. 2004-2005 gt3 is 380 hp but most that have been tested produce 390 min hp and some at 400! (Bhp) Gt3 feels (is) faster because the torque curve is flatter and much higher to redline and higher than x51 motor by about 30 lb/ft for a longer duration Like Jake says its all about torque and ability to maintain this torque to redline. Gt3 does an amazing job of keeping good torque to redline. If you look at some torque curves for bothy cars side by side you will understand why gt3 is much faster. Especially on a long track where it can stretch its legs.

^^^ less drivetrain loss too due to 2wd as well as lighter weight on the GT3.

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FWIW... Over the past 3+ years I've witness many dyno runs for compliance ona Dyno Dynamics machine. They historically produce anywhere from 5-10 % less than a DynoJet does. We (POC) are switching to Dyno Jets only this year and will have a portable one out this weekend at Chuckwalla for testing. It will be interesting to compare the results... I've dyno'd 3 maybe 4- X51's with the highest reading being 309 rwhp on the Dyno Dynamics dyno. That car will be there this weekend so I can make a apples-to-apples comparison. Regular old 3.6's make 280-290 by comparison on that same dyno, a difference of only 20-30 rwhp (=/-). YMMV.... FWIW my motor, 3.6 bottom with 3.4 heads (lightly decked), OEM cams, & FVD cable TB hit 305 rwhp on that Dyno Dynamics dyno. It produced awesome TQ in that configuration but didn't much like it when I hit 8600 twice in a race. Boom.....

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Nice. Do you have a pic of the dyno somewhere? I would love to see the whole curve instead of just reading about peak figures.

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JR, I guess the sea level air in Texas is better than the sea level air in Calif. No one give me crap for the fuel curves, etc, the final tuned dyno was higher, tq moved some, and with better AF ratios. It is a 3.6 X51, race car, NOT a street car. Stock Porsche unopened block,heads, crank, although various add ons, "Special" tuning package, etc etc etc. Oh, and on a Dynojet.

nice flat torque curve from 4500rpm right to redline... wow! that thing must hussle

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Thanks. It does ok for a stock block/heads/cams/valves motor. Although I have been planning something new for even more tq and a better curve, hopefully it will all work out as I have planned.

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NASA adds 10% to the Dynodynamics readings so 309 + 10% gets me right up next to your dynojet results. I did however find a X51 at 315 on the Dynodynamics maching. +10% for that motor woudl be 346.5...

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Thanks JR, those are some great numbers for your frankenstein setup. In my experience, the Mustang style dyno's generally read a bit lower than the Dynojet roller dynos. Seems like you got some decent broad powerband. It seems like you are gradually dropping off above 6.5k though. I wonder if the x-51 intake manifold allows the power to keep going as in Viking's graph above 6.5k?

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I have tested them back to back, and yes the X51 will help, BUT not as much as the head work from the X51 does. That said, we do everything possible to make peak power at 6.5K or below, else I have learned that we have to use our solid lifter/ solid tensioner package that requires valve adjustments. The factory X51 engines make power right up to the rev limiter, which is very hard on the factory hydraulic valve train. Not even my modified hydro lifters are able to hold up with constant redline operation as well as our solid arrangement. The solids are a bitch to deal with, but to really turn it up we have learned what needs to be done..

^^^ Thank you Jake for that wonderful piece of info. So since the stock lifters are the weak point at high rpms, does one even need to worry about valve float since there would be no point in running high rpms, at least on a constant basis? Also are you sure you're feeling ok? I've only heard technical responses from you with no sales pitch whatsoever lately. It feels like I'm reading your older posts lately. I mean that in a great and refreshing way. Either way, thanks for the insight. Truly appreciated and what forums should be about.

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The hydro issues we see aren't valve float as much as other issues that take a lot of service time to show up. Actually I had oral Surgery today and am pretty much whacked out of it after having 5 teeth cut out, but trying to get a newsletter finished and etc. I didn't think that I had changed anything in the way that I post. I have been posting less as I just don't have the time. I enjoy posting and helping most of the time, but other times its just another form of stress that I need to avoid.

Redux pt2

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on a stock 996 gearbox shifting @ 6500 will yield optimal acceleration and keep you in the thickest/highest part of the torque curve... the 996 gears are actually quite tall so you don't need to go to 7000 or beyond.... it's there if you need it as you approach a corner and don't want to shift and then downshift... going that high is tough on internals and don't really get you more speed... in fact shifting beyond redline may make you slower as you traverse the weaker part of the down-sloping torque curve... in Viking's case... this doesn't apply as there is good solid top end power.... but the top end stress on the motor is still there and will materialize over time..

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egas Tb is that much smaller than a nonegas? Regardless that's a nice size gain...

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Yeah, not sure as it's en route to me now. Once I get it, I'll measure this one along with a stock one and report back.

Just got mine back from Maxbore. Looks great, fast service and only hundred bucks, how can you go wrong? Has a tag that says Stock bore 73.6mm Max bore 76.8mm, this is from a 3.6. Can't wait to try it. First event is first weekend in May at BIR.

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Crap, had a chance to measure against my stock TB and apparently, I've been sold a turbo version which is smaller. The numbers didn't sound right from the beginning and now I know why. I guess I'll need to send in my original TB.

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Just reading through this thread after doing a search- so what was the outcome?

Sorry, never got the chance to install it. The racing season got started, then the engine blew. Maybe this year in conjunction with the rebuild.

Sorry to hear that. I might beat you to it. And maybe some dyno results to corroborate any gain (or loss??)

hey guys... any updates on the bigger TB combo here ?

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I've held off on installing until I get a couple more mods in which I'm planning on installing everything together.

Negligible difference. Get short gears instead ; )

I'd like a who, what, where on the short gears please.

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Not really saying much. What setup, overall power, change in power curve, better throttle response, etc. I love people that say one liners and expects everyone to listen or believe them. Also, you are talking about $99 vs. $3k+. LOL This is the 996 crowd, not the 991 crowd.

I'm traveling. When I get back in front of an adult sized keyboard I'll respond in greater detail.

Did the TB mod and went to the dyno. Problem was I also installed a piggyback and did a completely new remap. They added a fair bit of fuel. Peak hp went down slightly but tq went up and there is a lot more meat below the curve. Net- much improved, but still need to play with it a bit to try and remove the dip at 5300. But no peak whp to boast about here. At the track (before short gear instal) the car felt more "drivable" with better response and broader power, starting lower. It comes on at least 500 rpm sooner now. But its also a long-stroke 3.6 vs 3.4 motor now so thats where the grunt is coming from. In short you can't use my results to come to any conclusion other than for $99 you are not going to see a quantum change in performance. As far as the 3-6 short gears are concerned they are awesome and track proven. You can do a search on Albins short gears and should have you questions answered. If not, I can weigh in.

what is that short gear business I am interested to hear more about it Did you also beef up the transmission fork and stuff while in there ?

I've always maintained that ported tb's should be looked at improving throttle response as a primary expectation. If it improves other areas like broader power curve or peak hp, that is a bonus and icing on the cake IMO. I can think of a lot of other places I can easily spend $99 and not get a single thing in return. Shorter gearing is a common racing trick to gain performance(ala Honda most notably). I've done it on some previous cars but I feel I want to keep a more civilized and relaxed attitude on a street car. What is your top speed and have you increased your redline?

You can't measure throttle response (well, easily) and it may well have been improved, but the main reason I did this was to make sure that my TB was operating at 100% after doing the motor and before going to dyno. It is 14 years old afterall. Would I do it again- yes. The gears on the other hand are unquestionably wonderful (at least in the context of a track car). The gear set is not cheap but worth every penny IMO. JRG said it feels like 50 more hp and that's about right. I should have done this long ago, but better late than never. I raced on the w/e at RA which prior was a 3,4 and barely 5 on back straight track. It's now a full 4,5,6 track with occasional 3 in traffic. Before, when shifting to 5 the car would perceptibly hesitate at around 135mph as wind resistance and the large rpm drop conspired to slow the car's acceleration. No more. Now strong pull from each gear- even 5 to 6. Top speed is 157 @ 7k. I have the table and can post it later.

Short gear table:

Very nice that you can hit 157mph(not that there's too many tracks where you'll encounter this situation) even with the shorter gears. Did you buy chance select your ratios based primarily on a specific or set of tracks?

G96 gear set from Albins is only available in these ratios. No other ratios I am aware of. I think they will work well at the tracks I frequent most though quite different (RA, Barber and Sebring).