Thanks for explaining this, I just installed a vf39 with the utec stage 4 map today. The car was being overboosted I guess since it was doing that thing were it shuts down for second in the middle of excelerating, really sucks, feels like your going to break the tranny! I noticed that the utec stage 4 is set at 18 psi, this kinda sounds like alot doesn't it? I turned the boost down a bit and it got a little better so I turned it down some more and seems to be working great. The car hauls ass!
I have a turboxs turbo back exhaust system that has one cat in the middle, turboxs uppipe, stock intercooler on there right now, walbro 255, sti 565 injectors and a bov. Is it safe to just turn down the boost.
Do you know if there is an external wastegate for the vf39? Whats with the helper springs?
Oh yea the car is a 04 wrx.