Emergency Electrical Power Shutoff Location

[RebekahsZ]

I've read several good threads about wiring the shutoff switch and the likely need to complicate things with shutting off the alternator.  Before I get to the point of wiring the switch, I'm in a bit of a quandry about WHERE to place the shutoff switch.  I understand it is best to have at the back of the car so emergency crews can get to it if the front of the car is all smashed and the engine is on fire.  I was thinking of putting the switch thru the tail light surround panel, but looks kind of complicated.  I want to add one of the switches in my next order from the parts site to combine some shipping with other things I'm buying.  Just looked at one of the switches in the auto parts store and it is a larger component than I had envisioned in my head and will require more space than I had orginally envisioned.

 

Can any of you who have installed shutoff switches on your S30s send me a cell-phone pic to demonstrate where to locate this thing for the simplest and cleanest install? SCCA/NHRA legal is the goal.

 

Also, I'm gonna need either a 2-pole or a 4-pole (working on the concept)-does anybody know if the 4-pole will work as a 2-pole (just don't hook up the second set of poles)?  If so, I'll order a 4-pole to give me more wiring options as I figure out exactly what will be required for my car.

Edited January 27, 2013 by RebekahsZ

[OhBilly]

For location, you will typically see them just inside the driver's window, usually mounted on the A-pillar. Remember that if an accident occurs, YOU also want easy access to the emergency shut-off. Another thing to consider is that an emergency worker's first priority will be to get you out of the car if necessary, and the drivers window is where they'll likely be going first. Plus, that's where an emergency worker would be looking for it.

 

EDIT: Just wanted to add that you could also have the desire to activate the shut-off while still driving on track. It doesn't take a crash to get a good fire started. In my opinion having the shut-off within driver's reach is the way to go.

Edited January 28, 2013 by OhBilly

[RebekahsZ]

Anybody ever used this switch?

 

http://www.flamingriver.com/index.php/products/c0015/s0001/FR1013

 

 

[beermanpete]

I installed that one in a freinds car a few months back. It works well enough but is not as easy to tell ON from Off as the type with a rotary knob.

 

My car has the Moroso 74102 located on right side of the cowl just under the windsheild. It works well and has the alternator cutt-off pole.

 

 

[RebekahsZ]

Thanks for replying!  Can you show me how you wired that?  I have several folks telling me that I don't need a dedicated alternator lug, but rather to just run a second heavy cable from the alternator back to the switch and to have the battery cable and the alternator cable share a lug on one side of the switch, rather than getting the switch with more than 2 lugs.  I posted this same question on LS1tech.com and got the attached wiring diagram.  Funny that the motor shown is not an LS1.  It looks like that push-and-twist switch from Flaming River doesn't offer any advantages for coil-on-plug motors; it doesn't really kill the alternator, rather it shuts down the coil.

 

I'm gonna be looking for a switch like the one above, but one that has an extra long threaded section so I can pass it thru both layers of the taillight panel.  Lots of the switches don't seem to have the little off/on label, so I may have to buy the switch, then if no label is included, then go and find that.

[RebekahsZ]

http://www.allfordmustangs.com/forums/5-0l-tech/246271-battery-relocation-w-4-post-kill-switch-install-w-pics.html

 

 

 

This switch from a Mustang sight refers to interrupting the voltage from the alternator exciter wire....I wonder if that would let me avoid running another heavy gauge wire?

 

I may just have to start the car and start yanking wires...

 

Edited February 2, 2013 by RebekahsZ

[RebekahsZ]

Can't find any switches that have a long threaded section to afix it to the body.  If you find any-give me a link.  I have found these T-handle style where the handle is long enough that would let me afix it to the body with the 2 bolts, then let the handle pass thru the tail light panel.

[beermanpete]

My Z has the alternator output wired through the switch. In my friend's Alfa we ran the ignition positive through the switch.

 

Using a 2-lug switch with the alternator connected to the battery side should work but will not allow an ammeter to be used. Also, some alternators will backfeed current through the exciter wire and keep the ignition alive (which is why we cut the igniton power in the Alfa).

 

Switching the exciter wire for the alternator will only work if the alternator is not self-energizing once the engine is running. Perhaps some are like that. The cars I am familiar with are not.

 

Flaming River is suggesting to cut the igniton power which works fine. This would allow using smaller wires since the ignition current is far less than the alternator output capability. I am not sure how necessary the discharge resistor they show is. It depends on the igniton system design I suppose, or the rules of the racing sanction perhaps.

Edited February 3, 2013 by beermanpete

[RebekahsZ]

Thanks so much, beermanpete.  The Flaming River instructions talk of disabling the coil, however, this is going on an LS2 car, which has 8 coils!  I've pretty well resigned myself to running the alternator wire thru the switch, but I'm really not excited about cutting up my harness.  I spent a lot of time sanitizing my engine electrical system and it will hurt a bit to cut back into it.  If I can come up with a tidy way to avoid it, I'll keep looking at a leisurely pace.

Edited February 4, 2013 by RebekahsZ

[josh817]

You need a kill switch with a resistor pack somewhere in the system. The ones I have worked with have 3 or 4 posts. Reason is for the alternator kill, you cannot disconnect a battery while a car is running with the alternator charging. You will blow the voltage regulator in the alternator by doing this.


I have seen a lot of racers put their switch in one of the air vents, or on the quarter window but that's a little ugly. If you have a cage, you can make a little sheet metal panel and put it there too. It needs to be within your reach, and the workers reach though. As a worker, we usually ask you first if you shut the power off; being cynical bastards, we check it too just to make sure. Also good to have it within your reach if you plan on playing at tracks with long straights or gaps between worker stations. We usually don't run with a big fire bottle to your car so we don't injuire ourselves in the process so it will be up to you to shut everything down.

[Mikelly]

I'm running my MSD power to a toggle to cut it off.  If not, my alternator, which is wired to the main power switches (I have one outside the car and one on the dash) continues to run-on.  As to locations outside the car, I ditched the wiper arm on the driver's side (removed the whole assembly actually) and installed it there.

 

Mike

Edited February 18, 2013 by Mikelly

[Six_Shooter]

Different sanctioning bodies have different rules for placement and activation, check with the sanctioning body you plan yo run in.

 

I.E NHRA has rules about how far away from the battery that the switch needs to be within. This means that the switch location is dictated by battery location, and not necessarily convenience. They also have rules about whether the switch is activated by a twisting motion, or a push/pull type and how it would need to be activated, or deactivated in that regard. 

[RebekahsZ]

No wiring yet, but I mounted the switch.  I will probably mount another master shutoff switch near the driver before I do the wiring.  Anyway, the switch I finally went with was the one from the marine supply shop that has a longer post (designed to go thru a thick transom) to allow me to pass it thru the double-thick panel at the rear of the car.  Step bits rock!  Anyway, the photos pretty well tell the story.  Will add to the thread when I wire it, but that will wait until my ZG flares are done, since I will slip the wiring around thru the inner fenders.

[LanceVance]

I've seen plenty of people mounting the kill switch in the back of the car (mostly the drag crowd), but I've never been comfortable with having a kill switch I couldn't get to from the drivers seat, while harnessed up.

 

I'm planning on mounting a pull-cable attached to a kill switch mounted on the center console. The cables handle will be in a custom made recess, mounted in the quarter window (2+2, so it's a tad larger).

I've contacted a few glass shops about cutting the circular hole in the quarter glass and they all say it's doable, but if it breaks I'll just go with Lexan. Here is the recess:

 

 

Can anyone guess what it started life out as?

 

Few more:

 

 

 

 

 

 

 

 

If you guessed kitchen sink drain you get a gold star! The threaded body, nut and gasket design make it ideal for sealing against the glass. On the outside I'll use double sided mounting tape to go in between the steel and the glass, while the inside will be sealed with the supplied gasket and nut. I will also be powder coating it in a satin black to match the rest of the exterior trim.

 

Here are the part numbers, in case anyone is curious:

 

Recess - Everbilt - 02554

Pull handle - Rennline -EL20.21

 

I'm planning on using this switch (not pictured):

 

Longacre - (LA4578) Battery & Alternator Disconnect

 

I'm planning on using a brake cable disconnect from a Richie bicycle to prevent any issues while off the track:

 

Ritchie - (28-248-910) Break Away Quick Disconnect

[ktm]

Six-shooter nailed it.  You should investigate the sanctioning body you are interested in to determine where and how your switch should be wired up.  You should wire it up to the positive, not negative, side of the battery.  Wiring it up to the negative side will do nothing for you if you have a short to ground.

 

I installed a Flaming River switch under my hood.  I am not racing my car and after a scare where I had a short to ground that fried my entire front light harness from the combo switch to the short (a side marker light) and I had a fire, I installed the disconnect switch on the firewall near where the battery would be.  You can see it in the attached photo in the lower right corner.

 

 

[RebekahsZ]

Finally obtained an ON-OFF decal that isn't an advertisement for somebody.  I got it off Summit and it is a Moroso decal, but it was easy to trim the "Moroso" off of it.  In order to avoid having a sticky sticker on my rear panel, I made an aluminum circle out of some thin stock that I had laying around and stuck the sticker on that, then installed the assembly on the post of the switch with an additional nut.  Here it is.  Will wire all this next, but it will be at least a few weeks, maybe a month before I get to it.  Be advised, this is an NHRA-legal decal, location and switch, SCCA requires more elaborate decals, and I think they want a different location too.