Turbosmart BOV controller kit (controller + custom Raceport) BLUEThe Turbosmart BOV controller is an electronic device which controls the pressure signal to the BOV. It works by detecting a negative voltage change in throttle position. It then energises a solenoid to vent all of the air out of the BOV cap, causing a pressure differential between the piston of the BOV and the cap which will vent pressure from the intake system. Large diesel engines with larger turbochargers can experience compressor surge when