When I had an Evo.. on my first stage of mods.. which was boost guage, mbc, intake, exhaust set up.. I too was running at full throttle and noticed my boost hitting 25-28 psi.

Now I never actually went on local highways and started doing 110mph but I sure did get from 0-70 pretty damn quick, Ofcourse I didn't hear noises like you but anyway.. I went to have my car dynoed and when they plugged in there boost guage it had accurate readings and I was boosting 20psi.

I had a defi d guage by the way and I'm pretty sure those are known to read so many psi off... but that's what you get for a 100 dollar guage.

 

$100 isn't cheap for a gauge. Even if it was $30, it should read the correct boost, not 5-8psi off. That's unacceptable and not normal.

 

It was the shop 909 Motorsports that installed it. I am going to go and give them hell. I know I'm pretty sure I wasn't running 25 psi, I would have felt 25 psi. That boost gauge intallation must be wrong too. What should I tell 909 Motorsports?

 

really i dont think you would feel 25psi on pump gas basically it would end up pulling timing from all the detonation..... it would probally run worse....

 

you would feel 25psi in a evo...you'd know for sure....
i had a crappy "autometer gauge" that read 5psi more than it was ...for the longest i thought i was running 21 psi when i was really running 16psi...my profec b spec II saw to my boost being corrected... autometer gauges are known to be defective and dont' last too long...