Uncontrolled Boost?

daryl06 · #1 (**permalink**) 05-06-2009, 11:09 PM

I have an '06 Mustang GT auto with a 140ax nonintercooled kit. I have a 3.875" pulley.I was told I should be boosting 7lbs max. Any thing more is dangerous. When I had it on the Dyno( Mustang Dynometer) it read 10.1 lbs of boost at 6134 RPM. And when the tech shut it down it shredded the brand new belt(6 rib).Before this, one time I tried WOT on the street I swear i saw 12lbs on my wideband.They are saying this could be a bypass valve problem. True/false? Any help to solve this would be appreciated. Thanks.- Daryl

jared@lethal · #2 (**permalink**) 06-01-2009, 09:30 PM

Quote:

Originally Posted by daryl06

I have an '06 Mustang GT auto with a 140ax nonintercooled kit. I have a 3.875" pulley.I was told I should be boosting 7lbs max. Any thing more is dangerous. When I had it on the Dyno( Mustang Dynometer) it read 10.1 lbs of boost at 6134 RPM. And when the tech shut it down it shredded the brand new belt(6 rib).Before this, one time I tried WOT on the street I swear i saw 12lbs on my wideband.They are saying this could be a bypass valve problem. True/false? Any help to solve this would be appreciated. Thanks.- Daryl

Daryl,

That's definitely a lot more boost then you should be seeing. I recommend first checking to make sure that you're reading the boost correctly with a mechanical gauge. You can T the mechanical gauge into the line that feeds the fuel rail pressure sensor located on the fuel rail. After you do that let us know what boost you're seeing at WOT. Besides that I'll have to check with Mike to see what he thinks but it's definitely more boost then you should be seeing with that pulley size.

Jared