Grimmspeed Manual Boost ControllerWelcome to the most refined manual boost controller available on the market today. During development, we worked hand in hand with tuners across the country to develop this device and ensure that it solves legitimate problems that they have with other existing boost controllers. The GrimmSpeed MBC allows you to raise OEM boost levels in a quick and efficient manner through superior boost range and ultra fine resolution (. 25 PSI click). Adding the MBC