How to Properly Ground a Race Car

[Ed Wright]

Originally Posted by Jeff Niceswanger

Don't go directly to battery on the positive side if your running 16 volt battery's . You will have to connect to kill switch, so you are not charging your ECU and MSD during charging . They charge at 20 volts ,and I found out the hard way it will pretty much damage everything in your car ......

I learned the same expensive lesson. Both of my 16 volt chargers also put out over 20 AC volts. Had to replace the ECU & MSD. Not going to say who did it (not me this time) but me charging plugs in the fender were originally also shut off by the battery shut off. Had to change that so I could plug in & charge my batteries with it shut off. Sure don't want to charge them with that switch "on".
Instead of running the ECU, fuel pump, and fans through the toggle switch on the dash, I power them from GM fuel pump relays, turned on & off by the toggle on the dash. ECU has it's own roofer relay. I was seeing some voltage drop running all that thru the toggle switch. Power for the relays are double 10 ga wires directly from the batteries. May be over kill.
Everything, including to the batteries ground to a stud on the back of a cylinder head.