50mm blow-off valve

Blow off valves are needed to keep boost psi from damaging the throttle or the turbo. By releasing the pressure air when going from boosting to NO boosting in a short time line.  Example, going from a wide open "boosted" in the intake to slamming the throttle body closed causing a  "vacuum" in the intake.  There is a brief moment of pressurized air that is before your throttle body.  IF excessive enough can damage parts. So the blow off allows that air to get out.  Plus is sounds cool.  All of our turbo kits come with a 50mm blow off valve.