I have a 2001 Subaru sti ra, and I’m currently having a wee issue with boost. On boost the psi is fluctuating between 1 to 1.4 bar, mostly in 4th and 5th gear. What I’m wanting to know is any advice in this area on what part needs replacing/fixing? Also can you tell me what the factory turbo is for it? VIN = GDB-002851.

 

does the car have any non-standard parts on it, maybe a decat downpipe or a random induction kit that hasn't been mapped in yet?