€œElectronic€ in this case, refers to simply connecting to the engine heat riser valve:s control wire and signaling to close the valve. A delay of 2-3 seconds occurs before the valve closes and exhaust backpressure builds to retard the engine revolutions vehicle speed. Automatic transmission equipped trucks have this function combined with the BD AutoLoc or TorqLoc computer. These trucks only require a basic wiring harness. A stock automatic equipped Ford truck, prior to 1999, will disengage the convertor clutch when the accelerator pedal returns to idle, the brake pedal is touched or when the truck accelerates. Since 1999, the convertor clutch will remain engaged until the brake pedal is touched. When the convertor clutch is not engaged the engine free wheels and the engine rpm falls to idle with no transfer of retarding horsepower being achieved. BD:s BrakeLoc computer is designed to close the heat riser valve on the Ford Powerstroke and will maintain convertor lock up until a pre-selected vehicle speed. The BrakeLoc improves retarding horsepower from 5 RHP, when the clutch is not engaged, to 200RHP when engaged. BD advises the driver that this €œelectronic€ brake results in a extreme amount of delay or distance before retarding occurs; the amount of retarding force is 30% less than vacuum engaged BD vacuum engaged brake and 10% of the stock Ford heat riser valves that stick or bind. BD recommends, for instant and superior retarding performance, the BD Vacuum Actuated, with a variable orifice butterfly exhaust brake kit, be installed. It does cost more because of the design and kit content but it is an engineered safer retarding device.