Primary Wiring Path

[Steve McMahan]

Ok, I mocking up the primary feed from the trunk to the engine compartment, on the wrong side for most of you, so please accept the drivers side routing so I can ask my question without all of those questions. I’ve picked a positive cable path that routes the cable in the best low-exposure path I could find. I’ve got to make a few shields, mostly for incidental road objects (not a driveshaft or something huge), but no pics of that yet.

My question is the negative cable. I removed both of the transportation brackets from the rear of the frames and was wondering if attaching the ground to that point would be adequate for the main frame ground. I still intend to use a stock-sized battery cable from the engine to the frame. Also, I have several other grounds for the EFI harness, one of which will tie into that Eng to frame ground. If that sounds ok, beside using good connectors and star washers, any other points for attaching the battery to frame ground?

Do I need to run my 00 cable from the battery to frame ground, to the front of the car? For info that might affect your response, I am welding my subframe connectors to the subframes that each of the main grounds are connected to. Pics: Battery box in trunk, location where I would like to run battery ground(it’s right below the box). Thank you, Steve

 

[Don C]

It appears that you are mounting the battery in the trunk, is that correct? It helps when you ask a question like this that you tell us the reason for it. If you are mounting the battery in the trunk I would not rely on a ground through the body and chassis, too many old, corroded connection points. Run a negative cable along with the positive cable. The reason that the battery is generally placed on the passenger side, in the trunk, is twofold. One, the length of the cables will be shorter, shorter cables means less voltage drop in the cables. Two, the torque on acceleration tries to lift the passenger side of the axle and tire, reducing traction on the passenger side.

Were it me, I would probably run the cables on the inside, next to the rockers.

 

[Steve McMahan]

Wiring is on driver side because that’s where the starter solenoid is. I asked about the ground just because I wanted to make sure I’m not over-doing it. I’ve got the cable to do it.

I’ll try mocking in the rocker panel. I think there is room next to the fuel line .

 

[Don C]

OK, I guess I'm confused. What engine do you have? What side of the engine is your starter on? I thought that all Ford engines used on our Mustangs had starters and solenoids on the passenger side. In looking at your profile pictures it looks like the battery box is on the passenger side.

 

[Steve McMahan]

I’m swapping in a 5.0l from an 87 TBird, which has the primary electrical system on the drivers side; makes the swap easier by keeping that. It’s all explained in my build post . That pic shows the battery box on the drivers side.

 

[rvrtrash]

Running a negative cable to the engine block is the best way, because of the amp draw of the starter. Also, I wouldn't run any cables or have any connection points on the outside of the body. I would also mount the battery box on the right/passenger side of the trunk for weight transfer. Run the cable or cables over the wheel well and inside the rocker, even if you have to use extra cable to reach your connection points in the engine compartment.