A blow-off valve (sometimes "hooter valve" or BOV), is a pressure release system present in most turbocharged engines. Its main purpose is to take the load off the turbocharger when the throttle is suddenly closed. Blowoff valves are used to prevent compressor surge, a phenomenon that readily occurs when lifting off the throttle of an unvented, turbocharged engine. Unstable flow leads to the cyclic noise sometimes heard on high boost engines with no bypass valve. With a valve fitted, flow is maintained preventing the compressor entering the stall/surge cycle.
Maxpeedingrods provide quality Blow-off Valves which fit for various car models.