A pair of adjustable atmospheric ( Blow Off) twin piston valves for the Nissan GTR35.

These valves have been specifically designed and engineered, to offer extreme flow rate capabilityw ith an internal 50mm (2") bore. For fine tuning there is a variable spring preload incorporated and a ratchet type top adjuster that will allow for the positive and precise adjustment that your driving style demands. To ease installation a 360 degree adjustable vacuum hose connector With a choice of inlet and outlet connections the valves can be matched to your engine perfectly. This valve incorporates a unique conical, progressive rate spring that can allow for the retention of boost pressure up to 34 PSI which will be dependant on the state of tune of your vehicle. This unique spring design will also allow for unrestricted piston travel and flow volume regardless of the amount of pre-load adjustment added to the spring.