This is for an R50 to be raced in SCCA’s B-Spec class. We wired up an OMP kill switch with the alternator protection. I never found a good source of info so with the help of my friend (electrical engineer) this is how we did it.

’Hardest part was finding the switched wire to the ignition system: we located it inside the plastic rail just above the four coil packs. Now, before you go all “bomb squad” cutting wires - get a good multi tester and check for continuity between the wire you think it is and the 20amp fuse in the engine compartment fuse box. A good probe will allow you to check without sniping the wire.

There are two threaded studs in the ABS brake module area on my car so we put the switch there, went thru the floor board with a 3/8” hole for the cable to the in car pull handle. The cable to the hood’s T handle just runs under the hood.

Will post more photos as we finish up. You can get everything at Pegasus Auto Racing Supplies. Use a good switch though!!

Why all this? Why not just turn off the key? I have been upside down too many times, crashed, hit hard etc - make it easy on yourself and the corner workers to help you.

Generic wiring diagram - hard part is finding the ignition system wire

that fuse F34, is the power to the ECU and ignition system.

This wire has connectivity to the 20 amp fuse in the other picture.

May have gone nutz with stickers. There is a nice open area in that part of the engine area for the cable to bend.

you can see the two studs here, bracket is in white, switch does not have the key inserted.

Make the T handle easy to find for the driver.

 

Thanks for sharing the full setup. Your explanation of tracing the ignition feed from F34 and confirming continuity before cutting is really helpful. Mounting the kill switch on the ABS module studs is a smart choice too clean and accessible. The routing for the pull handles also looks practical. This will definitely help anyone setting up a proper race-legal kill switch.