Hi All

I've got a MY00 2000 Subaru, when on boost 1st and 2nd gear are fine boosting but when i hold boost in 3rd, 4th and 5th, the boost comes in ok then drops off then spools up again then drops it again and then goes again without any problem, ive recently changed the MAF Sensors due to revs going up n down at stand still cued that with the MAF, but now i get boost problem, been told its ova boosting but its not, any1 hav any ideas.

 

You say it's holding fine in 1 and 2, what does it hold at in these gears, and what pressure is it dropping off at in 3,4 and 5??

It could be a number of things, from a dodgy BCS to a weak wastegate and anything in between.

You need to post up more info on the car, mods ect.

 

I will check were its loosin boost, as for mods not alot really just 3" ss exhaust from turbo and dump valve, standard air box n filter, just put a new turbo on from a new age 06 wrx, put new gasket on. Think it might be the BCS tho or the piping, will give tha a clean or borrow my brothers. Question tho has the new ages turbos got a restrictor built in, cos ive got a pipe with summat in it from turbo to actuator and the 2p sized one thats on the bottom pipe from the BCS.

 

found the problem, new age uses different sized piping swappped it back to the old piping and runs like a dream lol, but just to make sure ive got the right brass pill in the pipe can any1 tell what size i need to use in the pipe for a (2000) Subaru Impreza 2000 turbo.