[redlin'r]

Hey guys, I am just curious what the stock Psi of the STi is. I beleive the WRX is around 14.7psi, so what kind of Psi does the VF30 turbo boost?

[4MLA1FN]

14.5psi

[thermobox]

the vf39(sti turbo) maxes at 14.5, and tapers off to 12.5. there have been cases of boost as high as 16.5 though, the wrx maxes at 13.5. i don't know what the vf30's max boost is

[redlin'r]

Originally Posted by thermobox

the vf39(sti turbo) maxes at 14.5, and tapers off to 12.5. there have been cases of boost as high as 16.5 though, the wrx maxes at 13.5. i don't know what the vf30's max boost is

Thanks a bunch. I appreciate it!

[bitabur]

Stock STi maxes at 14.7 psi - same as 1 atm.

[redlin'r]

Originally Posted by bitabur

Stock STi maxes at 14.7 psi - same as 1 atm.

cool thanks for some reason I thought it would be higher than the WRX, however in all reality the 14.7 PSI is more in the STi since it has a bigger turbo, so it is. What is the stock turbo in the WRX 13G? what is that equivalent to as far as VF series go?

[bitabur]

I don't think the WRX gets up to 14.7 psi.... probably close though.

[staticx313]

ya the wrx is 1psi lower stock... but that can always be altered

Robert~

[BoostdBoxer]

man i dont but my profec reported 21.9 PSI one day and I hit a hard fule cut

[steffen]

How high can the stock Sti turbo be turned up to?

[blueballs]

I wouldn't go for extended periods above 16 psi.

17.5 is fuel cut. You can get a fuel cut defender to get rid of it but I highly DO NOT recommend that. The VF-39 seems to be maxed out at ~16psi. The turbo for this car was too small IMO.

[ab954]

I have a PDE downpipe installed an i get a spike to 16(1.1bar) in second gear but it is stable at 1 bar every where else.

[blueballs]

Yea, that's fine. I tend to lean heavily on being on the safe side of things.

Spike to 1.1 bar w/ a dp... looks like you'll may get boost creep bad enough to get fuel cut if you add a catback. If you do, be prepared to port your wastegate.

[jspecex]

i'm sorry kinda of a newbie to turbo's usually work on allmotor but what is boost creep

[blueballs]

"The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down."

Boost creep occurs when the wastegate cannot flow enough air to bypass the blades. So what ends up happening is the air flows through the turbine even though the wastegate is fully open which results in the turbo spinning to higher than stock speeds. This can lead to premature turbo failure. Also, your ECU monitors boost and cuts the fuel if it goes above 17.5 psi for more than a second in order to protect the turbo/motor. You can see this happening if you watch your boost gauge and it will gradually keep climbing past stock levels.

Here is a very good site which will expain the basics of turbochargers (it was the 1st site I looked at to learn the basics):

http://www.howstuffworks.com/turbo.htm

There's like 5 pages of info that will help you.