A friend of mine has an EVO, with bolt ons(tubular manifold, IC piping, IC, ecu flash, etc) but it doesn't want to rev all the way out. Now my question is this: If you are not running a boost solenoid, or pressure under stock boost, will that cause problems? He is running 9-10 psi(whatever wastegate pressure is), so will that cause any problems? The car came without the solenoid, but I might be able to access one if absolutely needed.

Recap: Car is running spring pressure for boost, no solenoid, and it sort of "pops" at higher RPMs and won't rev to redline. Any ideas?

 

With out a wideband to say for sure, he's more than likely running too rich at higher RPM. He's not hitting the load cells expected due to the lower boost level, which would cause the very rich condition. At least get a MBC and set the boost to 20psi.

 

Yeah, thats what we are doing right now. Hopefully that works!

 

absolutely get a mbc. I had a aem tru boost with solenoid, it crapt on me after like 5 months.($300) got a mbc yesterday ($85) solved everything. good lock!

 

That pop you might be hearing is the engine bouncing off the rev limiter. Log the car and see where the rev limit is set at. Your boost pressure dont have anything to do with how high your car will rev.