NFRs2000NYC

The turbo is inefficient above 9psi. If you tune for 10-12, and you creep 2, you are still getting inefficiency up top, which begs the question, why do it in the first place? Not to mention, the potential damage to the motor boosting over 10 psi on a stock headgasket.

I am getting tuned for 9psi, and with my HKS/testpipe, I get absolutely no creep, as from downpipe to exhaust tip is 60mm straight.

I said it before, and I'll say it again, if you want big power, and high boost, you bought the wrong kit.

TRBOKEV

Do you have any data from Greddy to back up these claims of the turbo being inefficient past 9K? Flow charts etc?

I don't understand how this could be true when stock cars from the factory are running sometimes double that boost level stock with smaller turbos than the T518Z with 2.0 liter motors... (WRX, Pontiac Solstice etc)

NFRs2000NYC

I don't have the data, but a very well respected tuner on this board says the optimal efficiency for this turbo is 8-9psi. Since I don't know too much about the subject, I take the advice from people I know who do.

Having people double the psi on stock turbos isn't always a good idea, and definitely not something you should listen too. Again, if you don't plan on installing a headgasket, forget 12psi....or else you are looking at one expensive repair bill.

TRBOKEV

Data is fact, everything else is just hearsay IMO.


I wasn't saying they were doubling the stock PSI in other cars, I was saying that their stock PSI is double of what you are saying is efficient for our turbo, yet their turbos are smaller than the one that comes in the greddy kit.

Spec_Ops2087

Those motors don't rev to 9000rpms either where there is a MUCH higher flow requirement.

There was a board member who tried to run over 12psi and he said it just fell flat on its face after about 10psi.

TRBOKEV

True but the solstice runs a much smaller turbo, has a 2.4 liter motor with a 7K red line and it runs 20 pounds of boost from the factory..

Subaru runs a 2.5 liter with a 7K red line and 14.7 pounds from the factory.


Kinda makes you think, as both of these cars run really small turbos stock, but with more displacement which makes for more flow.


I did see the post where a 3mm HG was installed and they tried to turn up the boost and it just stunk though. I agree that this turbo isn't going to work in those type of applications. Some of us just want to find out where the edge is with he kit.

GT Motoring

Ive got the Random Tech 2.5in race cat pipes here, and extra o2 bungs here in stock. I can make something for you. Lemme know.

Spec_Ops2087

I should have skipped the rpm comment entirely because its only a small factor. Its really the engines in general that have completely different flow characteristics as proven by your statements. Some can run this turbo to 15psi or whatever and make power. But some (like ours) can only go to about 10psi.