trying to do some research on wether a plenum/tb is worth the investment and came across claims that the larger Tb from the GT2/3 may increase turbo lag.....anyone who has done this mod (preferably with ecu tune) care to comment?

was it worth it?

 

yes it does.

and also you should remap the ecu to keep the idle stable.

 

I was going to start researching this soon... do you guys have any links to where the problems are being discussed?? I thought the plenum was supposed to be easy bolt on power.... or is it the larger throttle body that's causing the issue??

drvik

 

Easy bolt on power?
Starting from a stock car, you have many upgrades you can do that give you far more bang to the buck than a plenum or a TB.
On stock turbos, even on upgraded VTGs, plenum and TB upgrades are of minimal consequence.

 

Thanks k... first will be an exhaust so the car can exhale better... I am still undecided about ECU because of the warranty issue... I was hoping that helping the car 'inhale' better would allow even the stock programming to possibly satisfy my needs... and possibly avoid a tune.... but if the plenum & throttle body cause actual problems on the stock programme then I guess they have to be considered as a package...

Still, does anyone have links to the specific thread where the rough idle and other problems being discussed...

drvik

 

wat would you suggest for 997.1tt with:
-ecu tune
997.2 gt2 rs intercoolers
-catless fvd exhaust
-looking to buy 65mm turbos

wat would have more bang for buck then plenum/throttle body?
thanks

 

tune is going to give the best bang for $ over all other mods, the exhaust should go with tune...the exhaust is two fold sounds much better than stock and makes car run stronger

 

Well, you aren't really going from stock. You already have a tune, exhaust and ICs.

I would invest in them upgraded VTGs and re-tune.
I would also install a meth kit allowing you to run higher boost without the race gas. That saves you money and gives you the ability to run at max all the time.
I would also look at the upgraded BRVs from EVOMS for example which will help you hold boost much better to redline.

Plenum, TB, manifolds, upgraded coils, etc... are, in my view, final stage mods that you would want to do if you are after that extra bit of power and are willing to go the distance.

Many cars here are running very very high HP/torque on their 997.1tt and have the stock plenum/TB but have upgraded fuel injectors for example.

 

++++1

 

It is a very worthwhile mod if the car is experiencing a restriction in airflow from the stock TB/plenum. That will not be the case if all the mods the car has is a tune. The stock exhaust is very heavy and restrictive. You would be far better served by changing that first (since it is currently the biggest restriction to airflow) After that you should consider changing your turbos or at least the turbo wheels to continue to raise power.
As long as your fuel system can provide enough fuel to prevent a lean condition, think of the engine as an air pump. The more air you can bring in per unit of time the more power can be made. You need to approach this problem in a logical planned manner. You dont just want to be hanging parts on the car. You should talk to a tuner to help you devise a plan that gives max return for your $.

I did the plenum/TB mod after I had done all of the above plus headers and intake piping. I found at that point that the larger TB/plenum actually decreased turbo lag and also gave more power up top!

 

Here is a 996TT thread showing some of what I was talking about...

https://www.6speedonline.com/forums/...num-996tt.html

 

so whats the general opinion?

Agency power plenum/TB or IPD for a car with upgraded turbos at around 650-700hp?

 

At that power level the TB/plenum mod should be helpful. I like the IPD better than the AP because the design looks like it would give better flow due to smoother less drastic splitting of the air. The AP looks like just a larger version of the stock plenum.

 

Is it necessary to lower the engine to replace the plenum/TB ?
Thanks

 

If I could throw another option into the ring...how about carbon fiber?

Not much of a cost increase over either of the other two options, but dissipates heat much more efficiently, sparing you those precious few degrees of IAT.... Available for both stock 75mm and upgraded 82mm throttle bodies too...

http://www.championmotorsport.com/pr...1-997t-tpc.htm