Have a inline pro kit stage 1 and wanted to go from 9psi to 12 psi. Also going to add a boost cutout for the exhaust to have a free flowing system. My concern is boost creep. I shoul be arous 400 to the wheels after I add these upgrades. Woold the 38mm wastegate be enough?

Also, I'm running 1 step colder plugs. Should I run 2 step now if my hp numbers are at 400?

Thanks,

 

yes and no.
38mm will be fine and2 steps colder is overkill.

 

What turbo?

 

Turbo is a gt30 dual ball bearing..

 

If the 38 is working fine at 9 PSI, it will work fine at 12 PSI providing nothing else changes.

 

38mm is fine. I ran a similar turbo on my STI (>410awhp) and it was perfect even at 26psi (different spring obviously).

 

Perfect..hopefully with a 3 psi increase and a open exhaust , I hit 400-425

 

i run 9 psi fine with my revhard manifold and the tial 38mm with no boost creep what so ever. The most psi you run the easyier it is on the wastegate.