nismorx7

K this may be a strange question to ask, but I need a ballpark. On a street ported 13bt, with a T04S04 .70 compressor housing, power fc, 47mm wastegate, etc, at what psi do you think I would be around 200hp. 3psi? 5psi? Just need educated estimates. If you need any more information let me know. Thanks guys.

FD Rey

Hard to say with that little boost. I don't know if you could even get a wastegate spring for that boost on a 47mm wastegate. And from your turbo is nowhere near it's efficiency even at 5psi. A more educated guess would be you'd hit 200rwhp at 3krpm at 10psi.

nismorx7

This is all theoretical, so say the spring exists, and I can run the turbo at 3psi or so. Any guesses?

FD Rey

don't see the point if it's "theoretical", but I guess at 2psi by like 5k = 200hp. It's not like there's an equation to something like this. You're simply guessing. Take into consideration that NA rotaries make 200rwhp all the time.

dubulup

better get a bigger wastegate or smaller turbo if you want to run 3psi...IIRC, Tial makes a 4psi spring.

my guess is less than a stock TII

nismorx7

why would i need a bigger wastegate? 47mm should be more than enough to handle spike at 3psi.....

FD Rey

a spike? 3 psi of boost is not a "spike" it's barely spooling that turbo of yours. BTW, what's the hole point of this "guesstimate"?

dubulup

turbo's build boost off exhaust flow, if you want to run this car up in the rpms you will need a HUGE vent (WG) to bypass your turbo to hold it at 3psi. I think you will have some boost creep. I don't know though, I've never tried to run an oversized turbo at an insanely low pressure...it's barely spooling.

more air in is more air out...

RenofHeavens

What is the point of having such low PSI and a large turbo?
Just doesn't make any sense to me.

nismorx7

Ahh i see. No I wasn't saying that the spike was 3psi, I was asking if you thought it would spike running 3psi... I understand your theory for the creep though. Thanks I never thought of that.