Help wiring a battery cut-off switch for racing

Hey all,

I am getting my Chevy II gasser ready to get back on the drag strip.

I currently have a battery cut off switch mounted, it cuts all power when the car is NOT running, but will NOT kill the car when it is running. So I need a little guidance to get it wired correctly.

- I currently have the cut-off switch on the positive battery cable (per NHRA rules).
- I have an MSD capacitor (for the 6AL) wired directly to the battery.
- The fuel pump relay is also getting power directly from the battery.
- I am running a standard (NOT a one wire) alternator.
- I am also using a Ford starter solenoid.

Any information or wire diagrams would be great!

Thanks!

 

The positive off the battery goes to the switch. Everything is powered off the switch..... Its pretty simple..


The only terminals to the batteries are the thick red, going to the switch, and the big black ground going to the frame.....

 

You're disconnecting the battery, but not the alternator. The alternator is keeping the car running.

 

^^^ he is right, I never run an alternator

 

You can get a switch that also cuts off the alternator wire from anything else. There is a third smaller terminal on the battery switch.

 

Had the same problem myself.....alternator

 

Click the link for instructions on the 2nd cutoff switch on Moroso's page (i tried to direct post that link, but it didn't work)
http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225

Hook up the Alternator charging output wire and Battery to one side of the switch and the supply to the rest of the car to the other (also including fuel pump, if thats were you are having it powered from) as the alternator needs to be allowed to release any built up power or the diodes in the alternator can pop.

Brian

 

That will kill the motor, turn off pumps etc, but you still have a live, heavy gauge wire running all the way from the battery to the alternator, which can cause a short circuit., sparks, fire, depending on why you threw the cut off switch.

 

The best way is to use a continuous-duty solenoid (Standard ign SS608) as the disconnecting means. Mount it up in the passenger foot well area'lose to MSD etc. The rear switch energizes the hot side of the solenoid, i set a switch near the driver tha gives a ground to the solenoid to complete the circuit that pulls in the solenoid.
I run the battery supply cable to one side of the solenoid, the altenator wire goes to this side as well. The other side of the solenoid gets the starter cable, ign cable and the general power cable.
When either the rear switch or the drivers kill switch the power is broken to the ign/car etc and the altenator feed is going direct to the battery so it cannot backfeed the ignition.
That way the power from the altenator is located right at the source power for the ignition etc and there won't be voltage drop.
Think about it for a while and you'll see the advantage.
Get rid of the ford solenoid on the starter, bad ju-ju. Go to powermasters' website and read thier tech articles and you'll see why.