Does the waste gate or blow off valve increase psi. I know they relieve pressure on both sides of the turbo and that the size of the wastegate is extremely important. Any info thanks.

 

First off, no, wastegates and BOV's do not increase boost pressure.

In simple terms, a wastegate is attached to the turbo compressor. Turbos often overspool, and the purpose of a wastegate is to open and prevent the turbo from running too high of boost into the engine.

A BOV goes on the charge pipe (between the compressor and the throttle body). When you shift, decelerate, or do anything where you're releasing the gas pedal, it causes the throttle body to close. With the turbo going 150,000 rpms or so, it will keep compressing air into the charge pipe, but because the other end of the charge pipe is blocked (or at least impeded) by the (semi-) closed throttle body, pressure is built up in the charge pipe. This pressure will start to push back on the impeller and create a kind of chattering interference called compressor surge, which is hard on the turbo cartridge and bearing, not to mention the fact that the compressor must then respool for a longer period of time before it reaches effective boost again. A BOV is installed on the charge pipe so that, when the throttle body closes, it will dump the compressor surge out of the charge pipe and reduce the respool time of the turbo, as well as prevent the surge from damaging the compressor bearing.

There are more details involved with BOV actuation, purge routing, etc, but that's the gist of it...

 

Couldn't have put it better.

 

Haha, well put Kappa

 

for shizzel dizzel

 

Thank you, thank you... glad I could live up to my reputation as "Turbo Groupie."

 

Haha Kappa, I LOVE THE SIG ADDITION