ProEFI iBoost Control System Hands down, the ProEFI has the best boost control that you will ever use!! Numerous ways to control boost include by vehicle speed, gear, wheel speed differential, time, ethanol content, and more!! A simple 5-position control knob is all the end user needs to choose the desired boost level. The fully integrated boost control system simplifies your system further eliminating redundant and inaccurate electronic boost controllers. The chosen boost level is also displayed on both the ProEFI CAN Gauge and Color CAN Display v2. Combined with the ProEFI Flex Fuel Ethanol sensor, your 5 boost settings will now be limited by the amount of ethanol present. The ProEFI automatically reduces or increases the boost levels available. This eliminates any possibility of overboosting ever again. ***The ProEFI iBoost system is ONLY able to be used with the ProEFI standalone. It cannot be used by itself.