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Discussion Starter · #1 ·
On my 70 Mach 1, I am in the process of relocating my battery to the trunk and wanted to see what others have done to route the BIG power cable to the starter.

I already have everything planned out for safety and meeting the full requirements of the NHRA for a trunk battery, including a trunk mounted disconnect switch (that kills power as well as stops the engine from running. i.e. breaks the alternator charge path) remote solenoids so that big wire is only hot during starting, and other smaller wires are fused.

So now I am just trying to figure out the path from trunk to starter for the BIG 1GA welding cable. The door sill trays are already full with the rest of my wiring harness, so that is not an option. I am more concerned with safety and reliability versus it being all hidden.

What I am thinking at is the following, but also trying to get others ideas.
Exit through the trunk floor:
1. Run along the underside of the car following as much of the subframe and sub frame connectors as possible.
2. Follow the rear subframe to the rear torque box then run the wire inside of the sub frame connector tube and exit the front of the connector near the torque box so less wire is exposed. Would need to drill holes on either end of the connector tube and add grommets.

Other ideas on what you have done? Pics would be great.

Thanks,

Tony
 

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Could you run it inside the car parallel to the rocker? Maybe run it through the seat riser and using grommets instead of up and over it- that way no hump in the carpet. Use cable clamps to anchor it in the corner of the rocker and the floor pan. I'd think inside the car would be safer from any road debris or (heaven forbid) impact damage. I can't speak for the Mustang, but I did this same thing on a '40 last fall. I actually ran it inside the frame rail and sleeved the entire length for safety. Probably overkill, but better safe than sorry, right?
 

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Discussion Starter · #4 ·
Thanks for the feedback and sharing the pics. Gives me a few things to think about.

With this winters changes, the car should be going form the low 10's to breaking into the high 9's so trying to be extra safe with a trunk battery, cleaning up wiring, and other things.

GT357SR, I was thinking about running it inside the rear frame rail, then break out into the subframe connector tube.

Rusty, I like how you routed the wiring and definitely easier. Seems to be very common doing it like that. I noticed that the solenoid is in the engine bay. Is that red wire always hot when the disconnect switch is active? I am locating my solenoid in the trunk so it is only active during starting, then the rest of the power going up front will be protected.

Also what is in that black box to the right?
 

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I use 1/0 welding cable instead of 1/0 battery cable, it's much more flexible than the battery cable and made from much finer strands of wire. And it may even cost less than battery cable.

If your cut off switch interrupts the alternator, never cut it off with the engine running, unless it's an emergency. Doing so can fry the alternator.
 

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Discussion Starter · #6 ·
Thanks.. did pick up welding cable and agree it is definitely much more flexible..
 

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The black box is to add weight but has been taken out and put back in my 1969 Mustang. When you race NHRA Stock or Super Stock you are weighed after each run. Going from track to track the scales can vary so you can add lead weight up to 100 lbs in the weight box to make the minimum shipping weight of the car you are racing.
 

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Discussion Starter · #8 ·
If your cut off switch interrupts the alternator, never cut it off with the engine running, unless it's an emergency. Doing so can fry the alternator.
John, Thanks for that advice. Given NHRA rules, I do need to kill everything so the engine stops, so I have it set up so the battery disconnect switch (DPST) will also kill the MSD ignition box rather than break the alt path. In addition I also have a continuous solenoid for the rest of the power that will also kill any other power from the battery.


Rusty,
On your 69 mustang, do you have the battery in the trunk? If so, how did you route the front portion of the cable? Looking at my mustang, with the headers, it is pretty tight around the starter and was looking for the best path to take with the battery cable to minimize header exposure. I will definitely need to use some heat shielding/insulation on that portion of the cable. I will not have a solenoid up front like you do in your Fairlane.

Thanks,
Tony
 

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Discussion Starter · #10 ·
Thanks again for the pics
 

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Mines a 65 but should be pretty similar. I ran a power cable and a ground cable from the trunk. I could only fit one in the sill, so the other one runs along the inside of the sill under the carpet(you can't tell it's there with the carpet on). They both meet up above the toe board, and then go through some grommets just behind where the air vent would be. I then ran them through conduit along the guard and down just before the shock tower, where the power cable goes through another grommet, through some heat shielding and straight to the starter solenoid which is on my starter. This car is a street car though which is why I didn't want cables exposed under the car, I guess for a track car it's a bit differernt.

You don't have to put the starter solenoid in your trunk if you don't want to, just run a fuse. I am using a 200amp automotive mega fuse, it is a slow blow fuse and won't blow with cranking, unless you are sitting there continuously cranking the starter with the car in gear or something silly.

I'll get some pics if you like.
 

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I moved the solenoid to behind the shock tower than ran my cable along frame and along frame connectors and up through the truck floor above the rear axel.
 

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Discussion Starter · #13 ·
Thanks for all of the feedback folks. I looked at a number of ways to route the cable, and it could not go under the car easily. Between the subframe connectors, outriggers to the door sills, and other supports, the cable would of had to go up and around too many areas, unless I started drilling holes all over. The best path was inside the car starting at the trunk, going over the right rear wheel well, then enter the car just behind the door and follow the inside edge of the door sill by the floor to to the floor kick area. Then there it will go through a hole and right to the starter so only about 12" of cable will be outside.

I am going to put the entire run in nylon braided wire loom for added protection, as well as grommets and even a section of rigid fiberglass wire loom when it enters the car behind the door for added protection.

I will post pics when I do the install. Waiting on the wire loom and some connectors.
 

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I recognize this is a 4 year old thread, but I have a related question. Like app01 I also have a 70 Mach 1 with the torque boxes used on the Mach 1. I have determined that my 1 AWG and 6 AWG battery cables will route nicely in the sill channel. The sill channel ends in a bulkhead in the PS A-pillar. I have my upper and lower cowl panels removed right now so I still have access to the PS air vent path right now. I can drill holes for grommets for the 1 and 6 AWG cables to enter the air passage way. A exit hole for the 6 AWG cable will drilled to feed it to the power distribution box mounted in the upper right corner of the passenger footwell. So the 6 AWG cable routing is taken care of. I want to route the 1 AWG cable through front bulkhead into the torque box and exit from the front torque box plate. I can then simply route the cable forward and under the subframe to the starter.
Anyone do something like this routing themselves. Any documentation and or helpful hints would be great. Drilling large holes from within the air passage way does not look like fun, but doable as I have a good right angle drill. I will likely drill the holes with a step bit to keep the drill bit length to a minimum.
 
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