Dump valve is sometimes referred to as blow off valve, diverter valve or compressor bypass. It is used in diving suits and hydraulic mechanisms. However, it is mostly used in automotives. Just like any other valves, its primary function is to prevent too much pressure. In the case of automotive application, it puts off compressed air into the engine. Whenever the engine shifts from a turbo boosted status into off throttle condition, there will be a pressure buildup and all the excess will be dumped by the valve. If you are thinking of buying one for your car, the guidelines below will surely be a help.