Originally posted by DSC
The wastegate releases the extra air the turbo generates. For example if you have a wastegate at 8psi it cannot go over 8psi.
When you shift the TB plate closes causing a surge of air back toward the turbo. This is of course bad (its spinning one way @ like 50,000 RPM, then gets stopped). The BOV releases this surge.
uh, the wastegate vents exhaust gas away from the turbine to regulate boost.
not that it releases pressurised air. big difference, as you described a popoff valve.