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Advice re IPD intake plenum and throttle bodies & tuning

markturner1960

Well-known member
Joined
26 Nov 2016
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215
Hi, I am considering replacing the slightly rusty exhaust on the car with a new one, as I cant stand to see dirt and corrosion underneath.....It's a man maths certainty that of course, the exhaust should be replaced with something fruitier , lighter and with more BHP....and of course the logical progression from that is that if you have freed up the exhaust, the inlet needs likewise....

So i have seen this: http://www.design911.co.uk/fu/pt697...05/996-GT3-RS-2003-04/Performance-Plenum-IPD/

which would appear to do the job, and the suppliers are claiming great things in conjunction with the new throttle bodies and was considering doing it all, including getting it remapped, all at the same time. All good.....

However, today, while idly browsing Rennlist, I came across this amazing thread, where this guy has built his own 4.0 litre engine based on the 996 GT3. When I got to this page, http://rennlist.com/forums/996-gt2-gt3-forum/632534-996-gt3-4-liter-8.html where he installing the intakes etc, he specifically mentions he is not installing the "snakeoil" IPD plenum.....

Now he seems to know what he is doing, along with his specialist tuner, so what's the perceived wisdom on upgrading these parts ? Are they any good? Will they work? Why does he think not?

Would be interested in what is seen to be the accepted route to liberating some BHP by tuning inlet and exhaust on these cars.

Thanks!
 
Hello mate,

Like you, I can't be doing with a rusty underside.
I recently fitted a complete Kline system with manifold headers. Replaced all the studs with titanium where possible. I also had an IPD plenum fitted in place of the OE. I had it tuned/remapped and gained circa 120 hp!
But mines a turbo and you have a NA. Obviously you don't get such spectacular results with NA. Although you'll achieve power gains, they won't be huge (20hp maybe).
To get significant power gains from a NA you'll require head work. High lift cams, aggressive valve shimming and maybe race gaskets (thinner) to heighten compression. Google tuning kits for specific models.
 
Thanks, I did not plan on going quite that far, but a little extra BHP always helps....the exhaust I was looking at gives up to 35 , the remap another 15 so I am told. The plenum and throttle bodies should give another 30 BHP according to the details. But I am not really interested in fitting it it does not do much, I also have an E92 M3 and there are a couple of induction kits for that that promise gains and dont deliver. I wondered if this was one of those, or why would the american guy poo poo it as snake oil?

I imagine it's a bit of a niche subject and should perhaps ask one of the specialist tuners etc.

Is there a particular company that I should speak to?

Cheers,
 
Having already been through Serge's build and following his path you'll be lucky to get anything near those figures. At best you'll get close to 400-410bhp but drive-ability will improve. If you really want gains you need larger displacement.

Think carefully before going down this route as it's a lot of ££££ for not much bang...

My expensive exhaust story:

http://911uk.com/viewtopic.php?t=74295&highlight=exhaust


:thumb:
 
Thanks Stuart - I wonder if I should make another post asking about exhausts in that case? Dont want to spam the forum with loads of posts, but this one does not deal with that ? what do you think?

I can see the issue along similar lines as your experience, firstly, there is not a huge amount of choice in this market, from what I can see there is:

1) Design Tek, in stainless steel, sold through design911 - Anyone fitted one? Any good? These seem nice quality, a sensible price and promise fairly good gains alongside a remap
2) Kline - look amazing and superb quality, but big money - £5K for a full system - add the fitting and remap costs and you are looking at £7K all in.....Again, anyone got one, can they comment on gains, experience etc?
3) Sharkwerks - muffler only and in America, so not really an option
4) Akrapovic - only seem to be available for 997 models upwards. Plus mega money...
5) M&M - appear to do a system, not sure who sells in the UK now..or the price

Could not really find anything else, the Manthey system seems to be only available as part of a package, and Europipe not around anymore...Miltek don't appear to make for the GT3.

So all in all, fairly limited choice. I would appreciate any advice or experiences on any of the above or any systems I am unaware of...and obviously any advice re the intake side of things , in conjunction with an exhaust or as a stand alone.

Cheers, Mark
 
It is never realistic to add up the stated hp increases of each item you fit to your car. Unfortunately is is all smoke and mirrors! Select mods will see maybe small increases in power but you will never get more than a total of around 20hp extra out of your car without spending a lot of cash.
GT3 is not about the power really. If you find yourself want a lot more power than buy a turbo or GT2.
 
You should also consider Cargraphic

http://www.cargraphicts.com/index.php?id=129545&L=1

I have one of theirs on my 993; it's very well made & sounds great, especially at WOT!

I have an M&M Cup exhaust on the 996 GT3 and although it has side cans, it's too loud for most UK circuits without additional silencers.

My advice is not to be tempted by a cheap exhaust; there's a reason why expensive exhausts still exist & are expensive. Poorly designed headers can rob you of 10-20 BHP on their own. It's very easy to claim power increases but very few will back these claims up by verified independent tests.

If you are going to materially improve the intake side, you are looking at porting & polishing the heads, fitting the 4.0L intake plenum + intake manifolds + injectors. All this requires a lot of re-engineering to accommodate the differences between the 996 & 997 and will cost you around £10K for parts & labour (I'm guessing here). Come back next year when my 4.0 litre is built and I'll know exactly :grin:

What you really need to understand is that the 996 GT3 isn't a platform that is easy to extract more power from; Porsche did a pretty good job and didn't leave much on the table for tuners to extract without spending a ton of money effectively making the engine 997-spec.
 
seconded on cargrahpic. its a well designed and flowed system so combie that with the IPD plenum, larger TB and re map you should see some decent gains.

mate has one on his GT3....got some decent gains , it sounds great but not too loud.

again its the sum of the parts that add the 25-30 BHP if you get the right mapper (wayne Schofield) and the right flowing exhaust
 
OK, thanks all, sage advice there.......It's not really a quest for more BHP at all costs, I just want a well set up, optimised system if I get a new exhaust - if I get an extra 20 -30 BHP as a result, that's great.

I think the exhaust is probably one of the most important mods or changes you can make - the full Akra system on my E92 M3 has transformed the car and I just love the noise it makes now, hands down for me the best thing about driving the car is the wonderful noise the V8 now makes. So if I can get the same thing from the GT3, I will be very happy.

Comparing the prices of the Cargraphic ( most expensive at around £6K) and the M & M ( around £4.5K) with the Kline ( around £5K) its a difficult choice.....The Kline might get the final vote being titanium while the others are stainless steel.....However, its all a bit more than I had initially planned to spend, so I may wait awhile , as I want to get the suspension and geo done first....

Thanks for the advice,
 
mark, great to chat earlier and PM sent

sometimes worth looking into getting an exhaust fabricator to build and flow one too. they can do some amazing things these days from custom headers to full systems.

NW
 
I went to see Steve today at Viper exhausts, as I had to drop the M3 off at a bodyshop in Stock, so it was only a few miles away. He is going to send me some prices but seemed very knowledgeable and a very nice guy. Lets see what he comes up with! Rgds
 
nice one. its no frills but steve really knows his stuff. anyone that used to build exhausts and headers for F1 cars with all sorts of exotic materials has got to be worth a punt.

he still does work for BTCC teams I think.
 

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