I have been known to ask why we should have to do a pull on a dyno. I guess this answers that....

 

Awesome.

Congrat's to you. Many happy, safe miles.

 

I was told that the AWE package (that you have) will enable our cars to pull on stock 996TT's......

Any comments on that?

 

I wonder why the problems are coming up on the normally aspirated car (particularly the 997s) in contrast to those who posted with supercharged or myself ( and other 997tt posters ) with the Turbo .

Any theories?

 

can you post a sound clip of your car? I would loooooooooooove to hear that thing!

 

Thanks AWE for saving me money. I hope RPM reads this thread.

 

Quote:

Originally Posted by yrralis1

I wonder why the problems are coming up on the normally aspirated car (particularly the 997s) in contrast to those who posted with supercharged or myself ( and other 997tt posters ) with the Turbo .

Any theories?

Just throwing this out there.

I am not making any analysis about the IPD part, I am only describing how the intake system works on the 997S (any every other NA Porsche intake since the 996):


Resonance tuning works this way:

Air flowing into the engine does not just go in one direction.

When the intake valves of a cylinder close, the incoming air then bounces off the closed valves and starts heading in the other direction. There is energy in this bounced pressure wave of air.

Instead of leaving that energy on the table, a tuned intake manifold like the Porsche 997S can harness the pressure wave to help move air into a cylinder whose valves are open.

As the air moves from a closed cylinder to an open one, it needs to pass through the plenum area in a reverse direction as it makes its way to the other bank of cylinders.

The air in the intake manifold does not travel only in one direction, away from the throttle body and plenum assembly.

Imagine if something were to disrupt the resonance tuning effect.

FYI, the resonance tuning flap opens at ~5k rpms.

 

Assuming 355 at the crank stock the 323 RWHP equates to 9% drivetrain loss (probably low) so the 350 RWP for the mods equates to 385 Crank (+5 over the X51!) or about a 30 HP gain.

I think that the 355 crank HP is a bit conservative so it is reasonable to asume that with this mod the 997S will put out close to 400 HP at the crank - very nice, definately on my mod list for next year.

 

I not sure that that is telling, since the 997S owners had the same satisfaction ratio (until Ian) based on the placebo effect.

As you might tell from my posts, as hideous as it looks, I believe that the OEM plenum is as good as anything.

Major kudos to AWE - both for honest reporting and a legitimate/proven power gain on their exhaust system.

 

Very nice results.

 

Neil, you doing the front?

 

I don't know about the 997S owner ratio posts . The 997tt had three posters : myself , Jason (atomic) , Larry(Humm) . I believe one more posted here as well . If so that's only four .

Myself and Jason experienced the same thing where the car took some time to adapt and then were pleased. Larry did not . He felt that his car remained the same . Of the three cars mine is the most heavily modded . I can hear a much more pronounced turbo spool upon accelearting and the car not only doesn't fade but pulls harder through each gear . Of course I my post is simply an opinion . Thus my post is not to be viewed as proof of anything other than I haven;t taken it off yet and if I had doubts I would.

As for "evidence" to support it I have my doubts even about dyno testing a small sample of cars as being enough to claim anything positive or negative in absolute terms .

FYI --My car's engine mods are -
Tubi Exhaust
Evo Headers
Evo Intercoolers
Werks1 Carbon Airbox
GIAC ECU
IBD Plenum

Lastly --If I decide to upgrade my Turbo's ( a bit nervous about the car's internals holding 700HP but considering it --I am approx 600 now) . I know whether its with the AWE system. The EVOMS system . Or the OEM Gt2 Turbos (three I am considering) --My plenum will be removed at that time .

But for the time being --It's staying .

 

Thank you for taking the time to gather the info!!!

 

Read my explaination a few post back. As far as FI engines,air dynamics is totaly different since the air is pressurized on the intake side of the cylinders and not drawn by them.

 

Actually, that explaination is not true. The air in the intake only flows in one direction for any given throttle position.. When a valve closes in an NA engine, the remaining opened cylinders on that bank increase in vacuum and immediately take whatever air the closed one is not. All air stays with the same bank. Redirection between banks begins at the throttlebody.