*Black Edition* Carrot Top Tuning Blow off Valve (BOV) MK4 MKIV A4 S4 1.8T 2.7T

Suitable for most turbo cars with an Air Flow Meter. Made from billet aluminium, this atmospheric diverter valve dumps the charge-air to atmosphere creating the "Whoosh" sound when the throttle is lifted. This increases both quicker throttle response and higher clamping load to maintain boost pressure more reliably. Unlike single piston or diaphragm diverter valves, this uses counter balanced springs and dual pistons to prevent the valve from leaking air into the intake system at idle. This prevents our diverter valves suffering any of the failures associated with single piston and diaphragm type diverter valves.All Carrot Top Tuning Dual-Piston Atmospheric Valves have been designed and built with the intent of venting 100% of the residual charge air remaining in your forced induction system to the atmosphere at throttle lift. While we have incorporated many elements into the design of the Dual-Piston valves to aid in their compatibility with mass air-flow sensor equipped vehicles, we