bad exhaust valves?????????????

[bretthejet26]

hi, i usually think the worst when it comes to poor performance, so im gonna throw this one out.... well i replaced the head of my 1g about 6 months ago (timing belt incident).... since then i've added a 2.5 downpipe and 4'' exhaust from buschur... and also a hallman mbc. now, im kindof worried because i think i've been detonationg BAD.. but its weird because boost has not been over 14psi (1 bar).. the most boost i've been running at any given time would probably be 12psi. i still have the stock fuel filter in there, and i dont have a thermostat in the car (im dumb i know).. but anyways my problem is similar to the bogging problem everyone has... but the wierd thing is that my vacuum on the boost gauge (blitz) reads -9psi at idle.... which is bad considering a month ago it was around -12_-14psi.. so im worried that there is something major wrong... or it could be just a vacuum leak... but if anyone has any symptoms of bad exhaust valves let me know? thanks

 

[TrustGs-R]

do a compression test. I've seen similar symptoms indicative of: bent valves, dead piston rings, or even a blown head gasket