BLOW-OFF VALVE (BOV)

The blow-off valve (BOV) is a pressure relief device located in the induction system, between the compressor discharge and the throttle body, after the intercooler. Upon quickly lifting off the accelerator pedal, the airflow is rapidly reduced, which causes flow instability and pressure fluctuations known as surge. This surge can damage the thrust bearing inside the turbo. One solution is to fit a blow-off valve, which vents the boost that creates the surge into the atmosphere. Another solution is to direct this air back into the induction system (between the air filter and turbo) by fitting a recirculation valve.