Blow Off Valve

[SilverBirdSeven]

What exactly would the gains be for a blow off valve with a turbo. I mean, I know it helps it work "more efficiently" but is there any real performance to be had? Thanks

[T-Punk]

no performance gains. It keeps you from having compressor surge and will keep your system alive longer. I wouldnt run a turbo system without one personally.

[grayman]

A4 tranny /M5 tranny + turbo = must have BOV.

A4 + super charger = do not need BOV
M5 + super charger = SHOULD have BOV

[gergwheel]

There are no gains, and it doesn't help it to be more "efficient". With turbos you do not NEED a blow off valve, some people think they help to make a turbo last longer. However no one has ever blown up a turbo because of compressor surge. It does seem like it would help the life of the turbo, but there is nothing proven. I have a pt52 right now, and no blow off valve. GM never put a blow off valve on the grand nationals, therefore they did the research and decided it was not beneficial to put it on.

Originally posted by grayman:
A4 tranny /M5 tranny + turbo = must have BOV.

A4 + super charger = do not need BOV
M5 + super charger = SHOULD have BOV

if you want to lose all of your boost while shifting and have to rebuild it in every gear then you should put on a blow off valve. Super chargers have a recirculating valve, not a blow off valve, this helps to prevent over boosting at idle. they don't need a blow off valve vause when you let off the gas the supercharger stops spinning as fast and that controls the boost level.