Compressor bypass valves can play a vital role in any successful turbo system because they not only improve performance of your vehicle but they increase the longevity of the turbocharger as well. The function of a compressor bypass valve is to relieve compressor surge (pressurized air normally forced backwards through the turbo upon deceleration) without reducing compressor speed. Repeated stress from compressor surge can damage the turbocharger and cause turbo failure. HKS offers three types of compressor bypass valves: Standard, Race, and the Super Sequential Blow Off Valve.