BD Diesel 2001102 Variable Vane Exhaust Brake The variable vane turbocharger design used in diesels today to reduce turbo lag, emissions and increase power can also be used to slow you down. BD utilizes this technology by electronically closing off the turbine vanes which can create up to 130 retarding horsepower. This braking force will help to maintain your speeds on descents and curves, giving you better control of your truck and load.The rotary switch offers three different modesStockVane Control OnlyVane Control with Aggressive DownshiftEasily and simply installs in approximately 1-hour by plugging into existing factory ports, tapping one wire and by mounting the rotary switch on your dash.Test shows that the BD brake was equal to or had better performance than our competitors brake at slowing down the vehicle.Approximately 70 psi of back pressure generated with BDs Variable Vane Exhaust Brake.