A friend of mine has just bought a classic WRX, not long come back from the clinic running 340bhp, all seems fine, plenty of history and extensive receipts, although there is a problem between 4-5000rpm. When fully on the power the boost just suddenly cuts out for literally half a second and then comes back in. Its definitely not lag, a few people have suggested wastegate actuator fault. (?) I have a UK2000 with TD05 and WRX with TD04 and have never experienced anything like it. Does anybody know what oil pressure it should idle at roughly with this spec as the reading on the gauge varies from time to time. Thanks

 

Sounds like the fuel/boost cut to me.
What else has the car had done to get it to 340bhp?
Has the car been remapped at all?

 

I couldnt say for sure until tomoro when i see him next and go through the paperwork, i know it definitely has bigger fuel lines, injectors and pressure regulator, and would guess it would have been mapped for the new setup at the scoobyclinic. It doesnt however have a boost controller which i thought a bit unusual for that much power. Other mods include complete de cat including manifold, FMIC, STi bits, and lambda sensor has been jettisoned. All temperatures seem fine although oil pres does seem to fluctuate a bit erratically.