[ma71supraturbo]

battery kill switch

I'm looking into relocating my battery, but to comply with NHRA I'd need to have a kill switch mounted on the rear of the car that when flipped would not only kill battery power, but would also kill the engine. It seems to me that if I just had the kill switch routed to the battery, the engine would keep running on alternator power. So how did you guys wire this up? I would like to avoid having the kill switch positive in the event I get rear-ended on the street...

 

[99rollaguy]

doesn't ur ignition run off of ur battery?

 

[99YellowStang]

it stays on i tried it once

 

[chevyeater-on-sf]

How about this- Run it on the B- side and attach your fuel pump ground to the switch. I didn't check it out but seems like it should work.

 

[ma71supraturbo]

How about this- Run it on the B- side and attach your fuel pump ground to the switch. I didn't check it out but seems like it should work.

hey! now thats an idea. Thank you. I wonder if the tech officials will get mad if the car runs for a few moments until the fuel pressure goes away?

 

[supracar]

It must be connected to the positive side of the electrical system.

http://www.nhrasportcompact.com/2003/rules/index.html (page 80)

 

[ma71supraturbo]

8:1 Batteries
All batteries must be securely mounted. Batteries may not be
relocated into the driver or passenger compartments. Rear firewall
of .024-inch steel or .032-inch aluminum (including package tray)
required when battery is relocated in trunk. In lieu of rear firewall,
battery may be located in a sealed .024-inch-steel, .032-inchaluminum,
or NHRA-accepted poly box. If sealed box is used in
lieu of rear firewall, box may not be used to secure battery and
must be vented outside of body. Relocated battery(s) must be
fastened to frame or frame structure with a minimum of two
3/8-inch-diameter bolts. ("J" hooks prohibited or must have open
end welded shut.) Metal battery hold-down straps mandatory.
Strapping tape prohibited.

8:4 Master Cutoff
Mandatory when battery is relocated or on any vehicle running
9.99 or quicker. An electrical power cutoff switch (one only) must
be installed on the rearmost part of each vehicle and be easily
accessible from outside the car body. This cutoff switch must be
connected to the positive side of the electrical system and must
stop all electrical functions, including magneto ignition. The off
position must be clearly indicated with the word "OFF." If switch is
"push/pull" type, "push" must be the action for shutting off the
electrical system, "pull" to turn it on. Any rods or cables used to
activate the switch must be minimum 1/8-inch diameter. Plastic or
keyed switches prohibited.

damn. Alright, so what all needs to be wired back to the switch to make it kill right away? Do you just intercept the alternator positive cable and run it to the switch? Does the starter need to be switched?

thanks

 

[ma71supraturbo]

bump

 

[OVRBST]

When you re-locate the battery you run one master wire from the trunk to the engine compartment, which can then be branched off via a distribution block to certain needed electrical devices (Stereo, alternator, etc.)

Just run that master wire from the + side of the battery to one pole of the cut-off switch, then from the other pole to the engine compartment. This will kill everything associated with the battery. When the current is broken (i.e. turning off switch, breaking + cable) everything electrical dies, including ECU, fuel pumps, ignition, etc. Car stops running instantly.

Problem is if someone turns it off, it will re-set your ecu, and erase memory pre-sets on your radio and clock.

 

[BLKMGK]

When you re-locate the battery you run one master wire from the trunk to the engine compartment, which can then be branched off via a distribution block to certain needed electrical devices (Stereo, alternator, etc.)

Just run that master wire from the + side of the battery to one pole of the cut-off switch, then from the other pole to the engine compartment. This will kill everything associated with the battery. When the current is broken (i.e. turning off switch, breaking + cable) everything electrical dies, including ECU, fuel pumps, ignition, etc. Car stops running instantly.

Problem is if someone turns it off, it will re-set your ecu, and erase memory pre-sets on your radio and clock.

One problem - you get rearended and the hot wire on the switch gets grounded - it's a mess. Cannot use the ground wire easily either - not without killing the alternator using a relay. You can put the switch further inside I guess and use a rod on the switch. Bleah!

 

[1BADGT4]

-OVRBST

I had that setup once, but ... only 2 out of 10 times the car would shut off.

We need to find out how to kill the alt somehow.