Mitsubishi Evo X Blow Off Valves
While the sound of a blow off valve indicates to everyone that you are turbocharged, a blow off valve serves a much higher function as well. When the turbo spools and you are accelerating through the RPM range, let off the gas and the turbocharged air is no longer needed but must be expelled from your forced induction system - this is where a blow off valve comes in and relieves that pressure. With an upgraded turbo or even just increased boost pressure, you run the risk of overextended your factory valve's operating range. With an aftermarket unit, the boost handling capability is increased, making your blow off/bypass system rock solid for any boost level you desire.
