Just for the record...about the different "psi" or "bar" that a 997.1TT, 997GT2 and 997GT2RS vs 996TT

...you have to take in consideration that the 996TT has higher compression ratio 9.4:1 vs 9.0:1

 

So you are saying that the 997's can get more boost then the 996,therefore they can get much more power HP,right ?

 

What I am simply saying is that 1.6 bar in a 9.0:1 is less than 1.6 bar in a 9.4:1

or in a 996TT 1.2 bar is more than 997 GT2 1.2 bar.

The advantage of using lower compression ratio is that you insure internals for high output applications ..and that additionally explains why de 997 TT & GT2 and for sure GT2RS has 60 lb injectors form factory instead of 45 lb that has the 996TT.

 

You are talking about Effective Compression Ratio (ECR). That's actually what matters when discussing strength of internals, not boost.

At 9.0:1 CR and 1.6 BAR of boost, the ECR for the 997 GT2RS is 23.2. In a 996TT with 9.4:1 CR, that same ECR is achieved at app. 1.5 BAR. That's the same amount of pressure on internals at two slightly different boost levels.

Regardless, 1.6 or 1.5 BAR is a heck of lot of boost for Porsche to run from the factory in a production car! That was my point, at least.

 

Scott

Which car,996tt and 997 GT2RS,at 1.6 bar will put out more power HP ??

Rolando

 

If you installed the GT2 RS's turbos, ICs, intake plenum and exhaust on an otherwise stock-motored 996TT or 997TT with the right tune, both the 996 and 997 would definitely make more power (thanks to the compression ratio and more aggressive, aftermarket tuning).

However; the GT2 RS was designed to run 620'ish HP in under any conditions, for extended periods of time (like on a race course), all while retaining it's factory warranty. The other two were not.

 

Thanks Scott

 

I was sure that the 997tt has the same CR as the 997GT2, both of which are lower than the 996tt.

 

Ya, I think you're right. I think the 997 Turbo varients are all 9.0:1. 996 is 9.4:1.

Rep for you.

 

You can run more boost with lower compression without fear of detonation to a point. Lower compression will also allow for operation on lower octane fuel. You will experience a bit more lag.

 

I was talking to the owner of Atspeed Motorsports a few days ago and we were discussing this very subject. He tought that the issue wasn't the block, rod or pistons, but the smaller components that would eventually fail. The rocker arms, valves, valve springs, rod bearings. Those are the weak spots in the motor, but who really knows, only time will tell.

 

Rep from me too

This may be yet another reason why 997Ts can be tuned for more power

 

Nothing much like DAMN HARD acceleration up to 216mph on REAL 1.95bar on bone stock engine + stock head studs

 

thanks bro...

 

Dennis you've been very sharp on your answers lately,you deserve it

SHOW THEM THE GIRLS