garrett376

This project has been going on long enough that there is about a 1mm thick layer of dust on the car in the garage! I went to get my tech inspection for my upcoming race in a couple weeks at California Speedway, it was noted that my kill switch was not mounted properly. The new rules for the POC mandate that the kill switch is to be placed behind the front shock towers. Yikes - in an early 911 this is no problem; but in a 964, it was truly difficult to find a place to squeeze in a kill switch.

This also gave me an opportunity to install the correct, 6-pole kill switch. I had been using an el cheapo $12 kill switch that is a 2-pole switch from my past race car. Well, I sprang for the $45 version for the sake of it working the way it should - kill the battery power, kill the DME (fuel and ignition) and save the alterrnator diodes by preventing a voltage surge upon cut-off. The 6-pole switch provides all of these excellent features with ease.

The hard part was:
1. Figuring out where to install the switch amidst all the A/C hardware in the trunk so it was behind the front shock towers.
2. Figuring out where to "interrupt" the DME the way the factory describes.

So, here's my adventure...

garrett376

First off, here's the difference between a 6-pole and a 2-pole switch.

garrett376

Here's the DME diagram - terminal #1 is the crucial wire to interrupt. Break this circuit, and the fuel and spark is killed.

garrett376

Interrupting that terminal #1 is the part that is cut-off with the poles labeled #2 in this diagram. The wiring diagram calls it the igntion switch and coil - but bypassing terminal #1 of the DME takes care of this.

Below is the kill switch wiring diagram for the 6-poles. It's pretty straight forward.

garrett376

Now, for the messy part - the CENTRAL ELECTRIC PANEL!!!!

You can see from the pics, that it's a mess. Removing it is like arm wrestling your grandma as you twist the wiring harness. Once removed, it is plug E that contains the lucky wire that needs to be bypassed...

To remove a plug, there is a handy slider at the top of the central electric - sliding this will unlock all the plugs. This took me about 3 hours to figure out - after mangling the plug (well, almost) I noticed this little lever and once you slide it, the plugs come off with no problem...

garrett376

Once unlocked, plug E can be removed (it's the second to the last one on the bottom right of the panel).
Shown is the small wire loop which is a brown & black wire. This is the secret wire to bypass! This wire is what is interrupted to kill the DME relay. So, the wire is cut, and new wires soldered to it. The wires soldered are run to the kill switch, and they are attached to the poles labeled "2" on the kill switch diagram...

garrett376

Now for the secret location of the kill switch - this was very difficult to figure out, but I think this is the only location it can possibly go without cutting a hole in the body and mounting the switch outside of the trunk.

I made this bracket from aluminum sheet purchased from Home Depot.

Curt911

Did you forget to put the heat shrink tubing on?

Great Post, BTW!

garrett376

I had to add a grommet to run the ignition cut-off wires - they go from the central electric, across all the A/C servos, through this grommet, to the poles on the bottom of the kill switch.

These pics show the grommet I added to the "firewall", and also the bottom side of the kill switch with all the plugs installed...

garrett376

Now for the final product! I kept the pull string in the same location as I had it before (saved me from pulling off the original sticker!

The problem I ran into was that the hood supports are quite thick, and I had to cut down the red key to be able to clear the hood. It took all my creative juices to chop up the key to keep it working where it cleared everything.

These pics show the battery wire routing, the resistor installation for the alternator protection, etc...

garrett376

Hope this helps those looking to install a kill switch the correct way on the 964. I had a tough time finding help for this - thanks to Bob Gagnon and Joey B for giving me the tips needed to get this thing wired right!! Success!! I fired up the car, and a turn of the switch kills it dead with no worries of frying the alternator! Love it when it works!

ThomasC2

Nice works, and pics!

garrett376

Hah! No, I was just showing off my one-handed soldering in that pic. I used electrical tape to seal 'em up before tucking away the central electric.

bhensarl

Genius, Genius! Great post, Garrett. Awesome step by step walkthrough. I think we need to somehow consolidate your posts about your new C4 into a single uber-informative thread we could call,"Preparing your C4 for the track: A Blood, Sweat and Tears Walkthrough by Garrett". Or someone else could come up with a better name. Oh, and you know, if you spray painted that aluminum bracket black, the whole thing would just melt away into the bonnet cavity. It might even look stock. But I'm sure you want to dismantle the whole thing just to paint it...

Brian

ltc

Garrett,
Very well done.

One thought though.

Are you saying that the POC would not allow me to drive my Cup car, as Porsche mounted the factory kill switch in an unapproved location?