SDOWD

I hope you may be able to provide a solution to the following problem :

Car : 1996 (Mar) Impreza WRX (import)
Mods : Stainless steel exhaust
Dump valve
I dont know if it is chipped !! (how would I find out ?)

Problem :

On full throttle acceleration in 1st gear I get overboost that results in momentary fuel cut off. This problem is also happens in other gears but very intermittantly.
I have put a pressure gauge on car and found that in 1st it will hit 16 PSI + (1.1+bar) while in other gears it (in general) runs at around 14 psi (0.96 bar), except when the above fault occurs when it hits ~15 PSI (1.03 bar). I have also heard "knock" when this happens.

I run the car on 95 octance with Millers Octane booster, so fuel should be around 97 octane with booster.

Also of note is that in 4th for instance when the throttle is floored at 3000 rpm, the boost rises to ~14 psi (0.96 bar) and then falls back to ~12/12.5 psi (0.83-0.86 bar) until 5000 rpm and then jumps to 14 psi (0.96 bar)

I have checked that main solenoid for clogging (none) and have also tried a different solenoid but this has no effect.

This is a pain as I now find that I am afraid to floor the throttle and actually get better acceleration by operating on part throttle.

Have you any pointers ??

What boost are they supposed to run ??
Regards,

Sean Dowd