Phish806

iTrader: (4)

Long story short, i did a battery relocation to the trunk and am in need of a disconnect switch to mount on the back of hte car if i ever want to pass tech and run at a track. I was curious if anyone knew of a switch that would look somewhat clean and not crazy obvious or out of place. I have found a couple black ones (Hella makes one that looks like a **** and jegs selss a cheaper all black one) that i could put down on the bottom where the black plastic mesh stuff is. Still not really sold on those two products though. If anyone has any suggestions or know of a switch that is not ugly as hell let me know. Thanks

carbonRX8

iTrader: (1)

I was considering placing mine behind the licence plate then remove the plate while at the track. This has numerous benefits including not having a switch on the outside of the car that fools can fool with. The issue that I am trying to figure is how to wire it to actually kill the car when switched off. I dont believe that just disconnecting the battery will shut off the car when on. I think some additional wiring is needed to somehow shut off the alternater as well.

BTW, I got my switch from Summit with my relocation kit.

Phish806

iTrader: (4)

When you hook up the switch you switch the ground side. When you throw the switch, it kills the ground to the entire car, thus shutting the car off and EVERYTHING that is powered from the battery. Behind the plate is a very good idea, i have not yet thought of that. Any other ideas?

carbonRX8

iTrader: (1)

Pulling the ground from the battery just opens the battery circuit. The chassis remains the ground for all other circuits.

In my experiments WITH OTHER CARS, pulling the ground lead from the battery WILL NOT shut off the car. The alternater provides the electrcal power while the car is running. Not the battery. I have not actually tried this with my RX8, but might tonight.

Phish806

iTrader: (4)

The battery is the common ground for the whole system of hte car. without the connection to the battery, the frame of the car / the car itself can no longer act as the ground. Atleast i am pretty sure this is how it works, try pullin the neg off the terminal when the car is runnin and see what happens ;-)

Phish806

iTrader: (4)

Your right, after some research NHRA rules say it has to be on the positive side of hte battery. However i have found people that have done it both ways. On the positive side then yes, you would hvae to find a way to cut the alt. also. This could get tricky

MazdaManiac

iTrader: (3)

Uh, no.

Your switch has to be wired in such a way that it removes the battery AND the alternator from the circuit.
That's why the make dual-circuit switches for cars where the common positive isn't the alternator.
A kill switch in the rear with a rear battery location the way most (if not all) of you guys are doing it is only a battery cut, not a true power cut and does NOT satisfy the NASA and SCCA rules.

carbonRX8

iTrader: (1)

So, to do a kill switch with the minimum requirements to meet most if not all requirements of tracks and sanctioning bodies, you need to interrupt the battery circuit and somehow isolate the alternator circuit, correct? The only way that I could imagine that would be so somehow have a relay on the alternator circuit that is closed when the kill switch is closed and open when the kill switch is open. That way you could just run a small wire to the kill switch in the back to control the relay in on the alternator on the front. Sound reasonable?

Would be nice if there was a diagram describing this, or whatever actutally works, on the forum...

Phish806

iTrader: (4)

On a street car, where the kill switch is always on, wouldnt the relay for the ALT end up draining the battery if left on for a long period of time without starting the car?

Flaming river sells a dual sircut switch for the alternator circuit to be cut also, but i am unsure how it would be wired in to the alt on our car to have it shut down that circuit as well.

MazdaManiac

iTrader: (3)

No, you just put the switch up-front, connect the battery positive right to the alternator, then to the fuse box with the interrupt switch before the main fuse.

Phish806

iTrader: (4)

If this is true, there is a line running from the battery in the trunk to the alt, then from the alt to the switch that is mounted on the rear of the vehicle and back up to the fuse box.

Am i not following this? The way it sounds its alot of line running from the front to the back and vice versa. Also, if your killing the power in the front of the car after the ALT, i thought there could be no power running to the front of the vehicle when the switch was thrown. This way the line from the battery to the alt would still be energised.

Maybe i am understanding this all wrong, but i guess thats why i created this thread.