Boost for stock turbo
 

Hey guys what is the highest amount of boost a stock turbo can put out, or whats the best for the turbo without putting to much stress on it?

Depends on if you have an Evo 8 or Evo 9 turbo.
I have seen spikes as high as 29-30 psi on my evo 8 turbo,but the boost tapers off quickly.
Evo 9 turbos will spike as high or slightly higher but not taper as much.

Remember the type of fuel is a concern when you are increasing the boost. My car was tuned for 91 @ 24psi.

I run 30 psi on my 8 turbo.

I spike at 33psi on e85 on my ported 9 turbo

Are you sure these high psi levels are safe? 33psi on a stock 9 turbo? wow, do you have any other supporting mods

We all have supporting mods in order to boost that high. You have to run either e-85, race gas or meth, but I boost to 30psi everyday. I have 110k miles on my stock bottom end and head. Pretty safe IMO.

A) He said it was a ported 9 turbo
B) He's running E85, essentially race gas.

That's still super high, but I'm sure he has everything in place that he needs for it to be safe. Will the motor last 10 years? I doubt it. But even the cars running 23 psi will last less time than those running factory everything (that's a given).

I ran 21 psi with hardly any taper (down to 19 by redline) on my 8, and I'd crank it up to 25 when I'd throw race gas in (no tune for race gas, this was back before switching maps was easy).

If it makes you feel better we turned up the boost on my STi... I'm running about 15.5 psi most of the power band :lol: Was about 12 stock, with a peak around 15 for a few RPMs.

I run 26-27 psi on 91 oct

I'm running around 25lbs on stock 9 turbo, probably going to bump it up to around 29-30 when I tune the meth kit. Running 93 Octane

I run 22 psi on 91 everyday and it feels smooth. I turned it up from time to time but i do have a headgasket that can withstand 40 psi plus arp's, valves and retainers.

It all depends on the car... I can turn mine up to 29 and no knock, But the car makes like 2-5 whp difference! There is no need to run higher boost when you car isn't making anymore power

I'm tuned to 29.5 on the stock non ported turbo with 44k and have spiked as high as 33.5 PSI. I am running e-85 and the highest I have heard on pump 91 was 27 PSI with 650 injectors and Comp 280's.

A buddy of mine drags his stock 9 turbo to spike at 38 PSI and holds at 28-29 PSI

38psi on the stock turbo?????

Yes then it falls on it's face. Spikes to 38, drops to 28, holds there and continues to fall to 19 PSI when he shifts at 7500 RPM or so.