Mirage L4-1597cc 1.6L DOHC Turbo (1989)
Air Bypass Valve: Description and Operation
Air Cleaner, Air Piping And Components
The air bypass valve, located on the air pipe between the turbocharger and the throttle body, is a vacuum controlled pressure relief valve. Due to the
volume of pressurized air that can be stored in the turbocharger air 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.