Made from billet aluminium, this atmospheric diverter valve dumps the charge-air to atmosphere creating the "Whoosh" sound most commonly associated with rally cars when the throttle is lifted. This increases both quicker throttle response and higher clamping load to maintain boost pressure more reliably. Unlike the Diaphragms valves this uses a single piston single spring to prevent the valve from leaking air into the intake system at idle. This prevents the diverter valves suffering any of the failures associated with single piston and diaphragm type diverter valves.