What Is It?

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Senior Member
what does BLOW OFF VALVE doing to the turbo???


And what is boost doing to the turbo???
Ok as soon as you let off the throttle to shift your throttle body closes. If your turbo is still spinning at that time(which it will be) where does the pressure go? It hits the throttle body and starts comming back to the turbo. This slows down the turbo almost instantly which "shocks" the turbo's shafts and bearings. A blow off valve(BOV) releases that pressure when your throttle body closes to keep from shock loading the turbo. It also helps you by letting the turbo slow down ALOT more slowly. So as soon as you drop the clutch in the next gear, your turbo is still spooled up instead of almost stopped. This helps you have a smoother transition between gears. BOV's are sooooo worth the money! I hope this helped you!
how does it know when to open or close. I mean what should I connect to it to it to work....???
it works by the pressure in the charge pipe. when the throttle body closes, all the compressed air is still in the pipe, and it pushes the valve open, until the pressure is equilized.
Exactly! Most BOV's are adjustable by simply turning a nut. You can also swap out springs on most BOV's also to change pressure.