Air Bypass Valve: Description and Operation

Intercooler And Components:

The air bypass valve, located on the intercooler pipe between the intercooler and the throttle body, is a vacuum controlled pressure relief valve. Due to the volume of pressurized air that can be stored in the intercooler and its piping (under high boost conditions), to prevent throttle overrun in the event of a sudden throttle closure, it is necessary to provide a bypass. The air bypass valve does this by using surge tank vacuum (created any time the throttle is in the closed position) to open the valve, thus allowing pressurized air to bleed off to the inlet side of the turbocharger.