Okay, a friend of mine and I are in a hot debate on how and when a wastegate works. My friend says it only opens when it sees a certain amout of boost. I think it opens when #1 it does see too much boost. But #2 it also opens when you let out of the throttle to let the turbo spool down. Which is right? I'm not certain, so I want yall's opinion. How and when does it work?

RubberDuck

 

I have a tendency to go with too much boost.

 

actualy it works on the exhaust side of the turbo, and when it does see to much boost it will let some exhaust go right past the turbo and into the DP, thus lower the drive pressure and lowering boost.

when you back off the throttle fast the drive pressures drop fast, but there is no way for the wastegate let the excess boost bleed off, as it is only an exhaust thing. so I think your buddy might have gotten you on this one.

now a blow of valve will do everything you described.

Diesel Rod