[chillindrdude]

Hi,

My 944 sits in storage, and I do not have access to an outlet for a battery tender. I have considered a battery cutoff switch to completely isolate the battery from the car during long dormant periods.

But, since this is a track car, and although no W2W racing is planned, and I welcome the challenge, I figure I'd go ahead and put in a legit 6-pole kill switch, no only as a battery cutoff but also a safety measure should things go awry at a HPDE.

I am purchasing this from Pegasus Racing. I think OGRacing carries the same.


I installed an odyssey 925 battery and the rennline mount with kill switch extension today.

So I had a few questions about the wiring for the 6-pole kill switch. I am referencing the below wiring diagram...


The wiring going to the ignition coil originates from the DME right?

So I "simply" cut this wiring and route this to the "Z" spades (which turns OFF when the kill switch is turned to OFF)

I read that the DME has a 11gauge power feed direct from the battery. Why can't I find that power line, cut that and route it to the "Z" spades instead?

Wouldn't that KILL the ignition coil AND fuel pump? and be more ideal/safe?

lastly, where can I buy a 1985.5 944 DME? (just in case as a backup)

[chillindrdude]

I think I am confusing the DME (which is Porsche speak for ECU) and the DME (fuel pump) Relay. The relay I believe sits in the fuse box right?



The above part is a known failure point, correct? So I should have a spare in my toolbox....

[TurboPooch]

While you are doing this project you might as well make it legal for NASA, SCCA, or PCA so you can find lots of info on how to do this on their websites and GCR's

Think of it this way....
1. The heavy lugs should interrupt the Positive voltage from the battery. I found it easiest to cut the clamp end off of the battery wire and solder on a lug on to the battery wire and the small feed wires. Use several layers of heat shrink and buy a roll of the rubber water sealing electrical tape to cover it up. Buy a short positive battery clamp cable to go from the switch to the positive terminal of the battery.
2. The smaller lugs (z and W)will be one pair normally open and one normally closed. In your diagram the Z will be open when the main is open and W will be closed. Get a short piece of 14ga 2 wire SJO cable and run it from your switch location to the coil. I drill a hole thru the firewall at the front of the battery and put a rubber grommet to run the wire thru and then over top the fender and down to the coil. Attach the two wires to your Z terminals and on the coil end attach one to the coil supply wire and the other to the coil terminal.
3. The purpose of the W part of the switch is to act as a shunt to absorb any alternator current that is being generated until the motor stops turning by running it thru the resistor to ground. This is the simplest way to accomplish this.

And yes, you should have a spare DME relay or jumper with you. If you don't want to spend the money for a spare DME relay that you may never use make a three wire jumper that will jump terminals 30, 87, and 87b together. This will give 12V to both the DME and fuel pump. Just remember to remove it when you turn the car off.

[alan t]

There should be a spare DME relay that I left in your glovebox