Blow off Valves (also known as diverter valves, recirculating valves, bypass valve, or BOVs) release excess pressure present in the turbocharged system. Excess pressure is either recirculated or vented to the atmosphere, depending on each setup. NGR Performance manufactures Blow off Valves, turbosmart BOV, bypass valve with a focus on performance and innovation. The Blow off Valves are designed for street use as well as racing use. NGR Performance manufactures best blow off valves with 6061 Billet Aluminum. The NGR Type-S Blow off Valve is the BOV Known for its unique whistle sound, the sound of metal slicing metal, that everyone loved from the Fast and Furious movie. The diaphragms are pressure tested to 100psi.