Last weekend I made a trip to MI and got a saab kit, much thanks to steve (acav2envy), i absolutely love this set-up, but im only reading 4-5 psi on my gauge, and he had the wastegate set at 8-9. Were thinking my exhaust may be the problem, after the downpipe, i have a 2.25 high flow but then my exahaust is just stock size (2") until the back it Y's off into 2.25 duals. So my question is, is that whats holding me back from seeing 8-9 psi? I plan on just doing a full 2.5 here pretty soon, just wondering if anyone has any other ideas as to why im only reading 4 psi?

Thanks!

boost leak would be my first guess, especially if you're saying the previous owner was reading 8-9psi off a good mechanical boost guage.

That's all my kit ran before I hooked up the boost controller. Check for boost leaks like oldskool said. And maybe try a different gauge. If that doesn't make any difference try and adjust the wastegate arm. Don't recall which way to turn it for more boost, but that info is on here somewhere. I got mine close to 6 with some adjustment to the arm. Also check the gasket between the turbo and the manifold, I had a problem with a leak there and it would only make about 3 psi, and it spooled real slow. Like 3 psi at 3000 rpm. i also had a 2.25" exhaust on mine after the dp. Once i hooked up the boost controller I could peak about 10psi(by about 2200) then bleed down to anywhere between 6-8psi.