I have a 2005 evo 8 with 19k miles (bought the car used) car has turbo xs 3" cat back exhaust, Cone air filter and Halsman MBC. Boost set at 19 psi, car ran fine for awhile, had to replace clutch (never do that agian) about 2 weeks later boost went- down to 11 psi. I tought it was the MBC so I uninstalled went back to stock tubes, now only boost to 2 psi to about 5000rpm then creeps to 5 psi to about 6000 rpm then i back it down. Anyone have any suggestions????.

 

Get a new BC your old one must have took a sH** , the 11psi was wastegate pressure. Get a forge for under 100. Call Dynoflash and see if he has any left. Check his vendor forum, he had some in stock I believe last week. That is my opinion.

Could also be your wastegate actuator broke at the turbo.

Check out this thread:https://www.evolutionm.net/forums/sh...ght=lost+boost