GReddy Blow Off Valves are easily adjustable to eliminate compressor surge and preventing premature opening, • Increasing boost response between shifts. • Each valve is made of durable cast and billet aluminum frame and the valve to diaphragm ratio provides performance that cheap piston types cannot offer. • Be recalculating the air back into the intake, valve noise is kept low while eliminating rich conditions between high RPM shifts. • The spring stiffness adjustment screw and the recirculation makes this valve ideal for anything from stock application all the way to race only use.