Last summer I finally got my car back to the track to make some passes. I had done a ton of stuff to it over the winter and one of the upgrades I made was installing an alternator for the first time. When I went through tech the inspector turned off the main power switch and the car kept running. I have since been told that I need to put a diode in the excite wire to solve this. I am getting ready to do this but I have no idea what size of diode I will require. The alternator is a 55 AMP Denso unit. Any input will be appreciated.