Need Opinions On Battery Cable Relocation

[Bimmerknut]

Here's my plan for routing the battery cable. I'm going to mount the block where the CAI would normally bolt up, since I'm using a modified PVC and K&N Filter. From there, down to the subframe and then over to near the top of the tranny tunnel on the driver's side.


I'm hoping that running it snug along the top will work and not interfering with shifter. In doing this I am keeping it away from the fuel lines. As mentioned in another post, I'm going to use JB Weld to mount nylon Ty-Rap mounts at 1-2 foot increments to secure the cable and instead of using nylon ty-raps, I'm going to use metal.


Once it's run to the rear of the tranny tunnel it will run above where the two fuel tanks come together, as far away from the exhaust pipe as possible and the directly above the differential it goes through the floor of the trunk in the center.


What I'm looking for are any flaws that you guys see that I'm not visualizing, especially those of you who have done this modification.

[farmerdanz]

I would run the cable through the cabin but that is just me.

[audioscience10]

If ur gonna run it that route just make sure its mounted up good. It wont take much slack to drop and let the driveshaft rub and that will quickly lead to it grounding out and possibly burning the car to the ground.

[gsumzzz]

Not digging the jb weld over the long haul.

[Bimmerknut]

If ur gonna run it that route just make sure its mounted up good. It wont take much slack to drop and let the driveshaft rub and that will quickly lead to it grounding out and possibly burning the car to the ground.

There will be almost zero slack. I don't want it taut as the flex in heating and cooling is necessary to reduce stress on the core.

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Not digging the jb weld over the long haul.

Then what would you recommend over JB Weld? I don't have a shop with a welder or anything like that.

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I would run the cable through the cabin but that is just me.

I feel that the less tight bends you have in the cable, the less chance there is of the shielding and casing cracking, as well as the core itself. Just going through the firewall and the cabin around the dash and just to get to the trunk from the inside would be higher risk of damage. But I could be wrong.

[hdx]

Run it in side the car on the passenger side for sure you will not be happy with it on the out side it will fit perfect if you run it just like a e30 with the battery cable holder and a short cable from there to the starter.
http://www.realoem.com/bmw/diagrams/a/s/21.png

[Bimmerknut]

Run it in side the car on the passenger side for sure you will not be happy with it on the out side it will fit perfect if you run it just like a e30 with the battery cable holder and a short cable from there to the starter.
http://www.realoem.com/bmw/diagrams/a/s/21.png

The cable that I have came from an E30. The schematic doesn't really help me with location. You say I won't be happy with it on the outside but you don't say why. If you have a theory, then I'd love to hear it. I guess I expect that if someone has an argument, then give a statement that supports your opinion. Thanks!!

[epmedia]

I'm not positive, but I'm pretty sure production cars with the trunk batteries have a dedicated steel tube to run the battery cable through. I would not run it under the car unless you have a way of doing this and have all the parts/equipment to make it last forever and not routed in an area that can get squished from jacks, bottoming out, moving parts, etc.. have to also consider heat, oil, vibrations, fuel, etc..

[jlse21]

I believe various people have done it successfully both inside and underneath the car.

I recently did it myself, and chose to route it inside the car, under the carpet. I figured it was better protected this way, and had no chance whatsoever of falling off or getting snagged on something underneath the car and pulled off.

I ran the cable through the hole in the firewall for the wiring loom, down along side the speaker, and along the floor, going underneath/through the seat brackets, up underneath the back seat, and through the hole you use to get a ratchet and socket onto the rear suspension mount bolts. There were no kinks or tight bends in the cable at any point, and I didn't have to modify or cut any part of the car. Just had to temporarily remove the back seat and the door sill trim piece to lift the edge of the carpet up. The cable is not visible or noticeable at all.

[NWlocal320i]

I believe various people have done it successfully both inside and underneath the car.

I recently did it myself, and chose to route it inside the car, under the carpet. I figured it was better protected this way, and had no chance whatsoever of falling off or getting snagged on something underneath the car and pulled off.

I ran the cable through the hole in the firewall for the wiring loom, down along side the speaker, and along the floor, going underneath/through the seat brackets, up underneath the back seat, and through the hole you use to get a ratchet and socket onto the rear suspension mount bolts. There were no kinks or tight bends in the cable at any point, and I didn't have to modify or cut any part of the car. Just had to temporarily remove the back seat and the door sill trim piece to lift the edge of the carpet up. The cable is not visible or noticeable at all.

Exactly how i did mine. easy

[Bimmerknut]

I believe various people have done it successfully both inside and underneath the car.

I recently did it myself, and chose to route it inside the car, under the carpet. I figured it was better protected this way, and had no chance whatsoever of falling off or getting snagged on something underneath the car and pulled off.

I ran the cable through the hole in the firewall for the wiring loom, down along side the speaker, and along the floor, going underneath/through the seat brackets, up underneath the back seat, and through the hole you use to get a ratchet and socket onto the rear suspension mount bolts. There were no kinks or tight bends in the cable at any point, and I didn't have to modify or cut any part of the car. Just had to temporarily remove the back seat and the door sill trim piece to lift the edge of the carpet up. The cable is not visible or noticeable at all.

So, where did you mount your block at? Firewall? Passenger wheel well?

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Exactly how i did mine. easy

Did you run your own cable? My length is limited as I'm using the one from an E30, although I don't think that the length will be too short.

[hdx]

The cable that I have came from an E30. The schematic doesn't really help me with location. You say I won't be happy with it on the outside but you don't say why. If you have a theory, then I'd love to hear it. I guess I expect that if someone has an argument, then give a statement that supports your opinion. Thanks!!

The main thing I wanted to show you in the schematic is the mounting block. The reasons you don't want it on the outside
is it will get damaged , wont look good ,and is a short cut. Do it right like the factory would. You want it on the passenger
side for weight distribution and available space . In my 77 there is a perfect channel and clamps sitting there empty like it
was meant to go there. It comes out super clean if you run it just like the main harness but on the passenger side .
Then do the engine bay just like a e30 with the mounting block and short cable to the starter.

[BIMMERBOYZ]

Have you considered how much heat you're exposing the cable to, choosing that route. Go on the inside.

[Bimmerknut]

The main thing I wanted to show you in the schematic is the mounting block. The reasons you don't want it on the outside
is it will get damaged , wont look good ,and is a short cut. Do it right like the factory would. You want it on the passenger
side for weight distribution and available space . In my 77 there is a perfect channel and clamps sitting there empty like it
was meant to go there. It comes out super clean if you run it just like the main harness but on the passenger side .
Then do the engine bay just like a e30 with the mounting block and short cable to the starter.

Ok. Gotcha. Part #8 & #9 are on the harness. I posted them in another thread. I guess I'll post them here too. Where did you mount the block? On the passengers side? Did you have a picture?

Attachment 458572

Attachment 458573

[Bimmerknut]

Heat? In the tranny tunnel? There's a LOT more heat in the engine bay and even greater heat on the passenger's side where the exhaust manifold is.
Jus' sayin'

[Bimmerknut]

Ok. Per this thread by Madhatter, I followed the path most of your were suggesting.

http://forums.bimmerforums.com/forum...d.php?t=586880

My plan was to go in through the rubber flap 90-degrees left and then 90-degrees right into a small hole that I enlarged to a 1" hole that comes out just above the glovebox.



Down to the floor, under the carpet, I saw the metal tabs that hold the cable secure. It was run through a channel where the passenger's seat adjustment level is, across the rear floor, also with more metal tabs that you bend over against the cable to hold it secure.



The way it lies now, the mounting block for the engine bay is going to have to go right there where the end of the cable is. I can't get any more length out of it. And as I mentioned for the rear, it's going to have to sit behind the rear wheel well.


From there it snakes through a space that allows it go behind the upholstery card under the rear passenger's window.



It follows the fuel filler pipe and comes out into the trunk right where the grey plastic breather tank is.




The problem is that the cable is so short that it will no support a battery placement in the center on the trunk. The only place it could go is on the far right, behind the wheel well.