Quote: So anyways, why wouldn't having a separate power and ground buss for the race car stuff not work? So far that MSD seems to be happy the way it is.
Like this in the picture, except not grounded to the chassis... The rest of the stuff like fans, water pump, fuel pumps, lumped in with the car stuff like lights. BTW, this is kinda how the car is wired now and the box sticking into the space a passenger's legs would normally go is a hassle.
It looks like someone tried to do a tidy job here. But I see something I don't like. Why have 6 relays that are nowhere near the device they are controlling? Also why control the relay with the same size wire that feeds the device? I would suggest placeing the relay near the device, water pump, fuel pump, fan, etc. Feed the relay with sufficient gauge to run the device ( 12ga, might even need larger) direct from the nearest power source. I like to use the battery cutoff positive feed terminal for the fuel pump. The alternator output or firewall pass through for the fans, etc. The control circuit can be light duty. My relay power feeds run a fusible link. They could be fused but my feeling is if the water pump, fuel pump shorts bad enough to kill the fusible link that item is toast anyway. In the pic the relays are on the motor plate for the water pump and 2 fans. The alternator on one side, coil and crank trigger on the other. Coil and crank trigger wire run down the right side. The alternator on the left Doug
