i have an S5 turbo and i noticed when i warm the car up to normal op. temp. i can boost up to 10 psi with no problem but after i drive for a few minutes i can only boost up to 6 psi tops. sometimes though it will let me boost up to 10 but what is causing this resistance? i thought it might be oil because i am coming up on an oil change but i never experienced this before. so any info will help

im confused, does it intermitantly boost 10 or 6 psi hot? or does it boost 10psi cold and 6 psi hot?



if its intermittant, than i'd have a look at the boost control solenoid, maybe it sticks?

boost 10psi cold and 6 psi hot

they do heat soak, when that happens boost drops

so how can i correct this????

Your IC clogged or something in the way?

no i actually think that the actuator that opens the waste gate has gone bad. like i think that the actuator is not closing the waste gate all the way

The colder the intake temp charge the higher boost pressure will be. A front mount intercooler and an ambient air intake will help. So will a vented hood.

well i removed the boost control solenoid and now i can boost again, yet i am not sure what the purpose of the solenoid is.