Just read an interesting post on Rennteck regarding mid-level torque improvements available form 997 engines by using the larger GT3 throttle body on either a 3.4 ,3.6 or 3.8 liter engines. Has anyone had any experience with this mod ? The post was comparing the value of this mod over installing larger diameter headers with regards to usable low to midrange torque vs high RPM hp.

 

Very interesting... got the link?

 

Her's the link and have copied the specific comment that got my attention. The original post was about headers.

"Having done both manifold experiments and also throttle body upgrades , I know from dyno plots that the throttle body gives real world Hp figures that can actually be felt and used on the road. Personally i dont fall for the marketing hype or the price tag that suggests something is worthwhile because its expensive. The TB upgrade on my own car achieved between 8 and 12hp gains with more results mid range than at peak power. Torque also increased by a significant amount . The mod has been verified by at least one other and suggested to be more worthwhile than manifold and ECU tuning put together...Its certainly worth a try , particularly if you can source a used throttle body and plenum , rather than paying new prices. In terms of value for money its an outright winner , direct bolt on (though you will need silicone reducers to fit the GT3 plenum to a 997 3.8 manifold and requires no ECU retune, the car does this compensation all by itself. "
To make sure credit is given where credit is due, the comments above were posted by berty987. Can't beleive this idea has never surfaced on 6speed. Sounds like cheap hp from a simple mod with no negatives. Too good to be true ?

http://www.renntech.org/forums/topic...-need-to-know/

 

Suncoast Porsche in Sarasota did this on a Cayman S. To take advantage of this you will need a ECU flash and exhaust mods....this this does work. Ryan is the lead tech their and he auto crosses this car and can tell you more about it.

 

It seems like an IPD plenum would make sense while you're in there, and maybe a Softronic 93 map if that's available in your area. I've got to think that hi-flow cats, maybe headers, and a B&M filter would round it all out.
By my calculations, that would equal 12HP (TB) + 12HP (IPD) + 15HP (ECU) + 10HP (Cats) + 8 HP (Headers) + 6HP (B&M), for a total of 25 HP.
Seems like the way to go if you're not into FI.

 

Are you intentionally being conservative with the final summation number due perhaps to some overlap? Just trying to follow your math...

So where do we try to source a GT3 TB from?

 

yes - it's not that I'm bad at math. Actually, it's a bit of a joke, based on a combination of overlap and false/exaggerated claims of the tuner crowd. The real number is impossible to know IMHO. Sure - you can test on a dyno, but that's a mess as results can be 'adjusted' by ambient temp, engine temp, tweaking the environmental compensation *****, etc.
I do believe that there are gains to be had, with the right mods, and I'd like to go down that path sometime in the future when my warranty expires, but I'm just sitting on the sidelines at this point.
I know some will say that most mods can be done while the car is under warranty - and I don't have an issue with that - but I'm personally going to wait.

 

Good point. There is a reason why I got a CPO and paid extra for it... certainy don't want to lose it. That said, GT3 TB and IPD Plenum sound like a potentially good combo. It will be nice to see some real dyno results though.

 

I believe the X51 throttle body is even larger than the GT3 throttle body. Not to mention it would be easier to modify a IPD plenum to fit the X51 throttle body. It has been done quite a few times before.

Dave

 

I see plenty of GT3 TBs for sale, no X51. In addition it sounds like there has to be fabrication done to some parts in order to make X51 work. GT3 sounds plug and play.

 

Is this implying that 1/3 of the power of the X51 package comes from the TB??

 

Interesting stuff...
Here's a good thread on X51. I think there's a fair shot at duplicating the HP gain with slightly different mods.
TB - yes
Headers - yes
Plenum - yes - but IPD - should be better!
Intake Manifold - maybe - I say no
Heads - no
ECU upgrade - yes, but aftermarket, like Softronic - should be equal or better
Airbox - maybe - X51 is too rich for my blood. I'd go with an alternative for most of the gain. Maybe just a B&M filter.
Then - add in Cats - not sure if X51 has special cats. If not, this should be a real power gain.
Did I forget anything?

Overall - most of the 36HP gain for less money. Maybe 25-30HP? Maybe equivalent 36HP? I can't believe it would be more than X51. So - I say 25-36 HP for around $5-6k, vs $15-20k for X51.

Of course, FI is also an option, if one would want to go that route...

 

Hi there

Funny you should mention this, I was talking to Porsche today ordering my X51 headers, centre radiator kit and X51 undertray for my 997.1 C2S

The Porsche tech actually said on the CUP 997's they fit GT3 throttle bodies and get very good performance increases and at a cost of sub £200 it seems good value. What I did not ask if its a direct bolt on mod?

So does anyone here know if the 997.1 GT3 throttle body directly bolts onto a 997.1S?

 

Thanks for the link Jack667! I will do a bit of reading tonight.

I may try sourcing a GT3 TB. Anyone know if this is plug and play?

 

If you have already put on 9974s.1 model the plenum and you want to put the gt3 tb the diammeter is defferent can you put it or you need other plenum?