My friend recently upgraded his stage 2 WRX to stage 4.
AP VF34 map
JDM STi TMIC
Perrin turbo inlet
Stock T-hose and "pill" from TD04
Now, problem is that he's only able to hit 12psi at max... that's what's read on AP live meter and defi boost gauge. Can someone point to where he should look as far as fixing the boost problem? He doesn't hear any whining or high pitch sounds which would point to potential leak problem...
Your help is appreciated.