Eric's Mtech2 Vert

[Cabriolet]

For those who are asking.
I started by pulling out the passenger seat, the whole rear seat and the glove box, and speaker grill.
Then remove the plastic inner black kick plate, the one that covers the doorjamb.
Remove the front passenger seatbelt, and the rear armrest.
Peel back the carpet.
Then there is an opaque plastic “S” shape that gets removed.
Now under the doorjamb there are clips holding a ton of wires. Pop those loose with a flat headed screwdriver.
Now go to trunk and remove the right side strut, right side felt/rubber liner, and then remove the back cover, which covers the motor area. Now you will be able to see a small whole at the floor level on the right side of the trunk. Feed the cable though that, then out the hole on the pass. side. Then down the floor covering it with that opaque plastic “S.” run it through the clips, BE VERY careful not to break them. Then up the wall behind the speaker grill and through the whole I showed earlier.
I had to add 8” more to the wire.


hope this help you.

Vivek, you need the cable, battery tray, battery cover, trunk cable holder, and the mount for it in the engine bay. cost me $40 for it all at pic'n pull 1/2 off day. (318 does not work. needs to be from a 325i)

[CorvallisBMW]

I just spent the last 12hours wiring in an amp and switching the battery to the trunk. all to find out the the wire was 6" too short.

Yes, I know this pain :(

The cab's double rear bulkhead means the battery cable has to do a bit more snaking around than in a standard coupe/sedan, which means it ends up being a little short. The solution is to either a) lenghten it, b) make a whole new one or c) use a dremel/sawzall on the bulkheads and make a tiny notch on the bottom corner to allow the cable to pass more "straight" through from the passenger compartment to the trunk.

[IronmanE30]

I think that moving the battery to the rear is a good mod. I am planing on doing this to our Mtech very soon. Nice to see some posts on it here before I start.

Cheers,

Jim

[Vivek]

What all do you need to relocate the battery, other than a cable from a coupe?

[durtyE30]

Looks good! FYI there is a tab to bolt the ground cable to near the wheel well, inside of the "new" battery compartment, no drilling is necessary. I've done this on all 3 of my verts, makes it easy to install an amp. :)

Thanks for the heads up, I'm tackling this job tomorrow!

I have no bumps in my carpet, I'm talking trunk carpet. Where would you pull it through otherwise? I need a bit more picture assistance there or I need to better review what you did.

e: after further review, i c wut u did thar.

I may do that as well, but I'm not too sure, it's not a big deal to me, but where does it punch through in the trunk? THAT is where I'm confused. I'm going to have to check it out in person more so tomorrow.

[Cabriolet]

durtyE30, if you run your cable under the door jam like it did there will be no bump at all and im running bigger than 0gauge.

Looks good! FYI there is a tab to bolt the ground cable to near the wheel well, inside of the "new" battery compartment, no drilling is necessary. I've done this on all 3 of my verts, makes it easy to install an amp. :)

doh! sucks to be me now.

[Dustn525]

Looks good! FYI there is a tab to bolt the ground cable to near the wheel well, inside of the "new" battery compartment, no drilling is necessary. I've done this on all 3 of my verts, makes it easy to install an amp. :)

[durtyE30]

I was completely unaware that was a complete WEIGHT until this thread!

I have a 0 gauge run I did for my stereo amplifier going ot the back anyway, so I'm just going to utilize that and make a new amplifier cable which is shorter. I figured I would have to cut the felt liner as well. I need to get ahold of the battery cover myself, and whatever mounts to hold the battery down (been bitched at for this in autocrosses before while it's in the engine bay, maybe not as bad if it's trunk located, but I don't want to get shit for it next time.)

I routed my cable differently, I didn't think there would still be the prepunched hole to punch out, so I just drilled and used a 0-gauge grommet. I obviously don't have the issue of cable length, but I do have the issue that my trunk carpet sticks up a little from where I ran through the rear. I used the holes in the seat backing and just ran straight through there, along with all my RCAs and speaker wire (I ran new speaker wires to each speaker, for impedence and continuity sake....my old radio harness was hacked up.)

[Cabriolet]

Barry, the battery cable it too short. so i have to get it lengthened this week. right now its tired to the wall next to the strut.

the dummy weight is the size of the battery tray in a coupe. but weights like 50lbs.

[reelizmpro]

Any pics of the dummy weight that used to be where your battery now resides?

[Cabriolet]

The carpet/felt/trunk liner that goes on each side of the trunk - you've shown it removed completely to fit the battery cover - you planning on trimming it and replacing or leaving it out completely?

oh that, yes i'm gonna mode mine.

[bmwphatpat]

please excuse my ignorance. but what/where felt liner?

The carpet/felt/trunk liner that goes on each side of the trunk - you've shown it removed completely to fit the battery cover - you planning on trimming it and replacing or leaving it out completely?

[Cabriolet]

How about the felt liner - how well does it fit with the battery cover? I imagine you'll have to modify it too?

please excuse my ignorance. but what/where felt liner?

[bmwphatpat]

props for tackling this on a vert! I've done this on a coupe but was wondering how hard it was on a vert...

How about the felt liner - how well does it fit with the battery cover? I imagine you'll have to modify it too?

[Cabriolet]

Yesterday was a super long day. It started with pulling out the entire interior.

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All the plastic under the dash had to be removed.

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Luke had mentioned that there was no good way to run the battery cable to the trunk on a convertible. I was very worried that this bulge was going to happen to me. But maybe the one he had seen had been done wrong but there is zero bulge in the carpet.
I took out the door rail and the clear/white plastic wire holder. Then I removed all the clips that hold in the wire-harness under the passenger doorjamb.

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After all that was out punching the hole in the firewall is supper easy. Lift the rubber matting and with a hammer tap on the pre-punched plate. I used a chisel to clean up the hole.

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NOW IF YOU WANT TO DO THIS AND SAVE HOURS READ THIS.
Remove the rubber boot and run the cable from trunk into passenger compartment then into engine bay. Otherwise you have to bend a hole so that the connecter can fit.

Run the wire through this hole. Not the little one in the back wall.

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Once the wire was run and stretched we mounted it to the front of the car. The holes for this are pre-drilled and accessed by removing the passenger grill.

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Wire gets sucked behind this speaker grill.

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To ground the car I drilled a hold through the body. Under the bumper so it can’t be seen. Sanded the paint off for a good connection then painted over it.

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On the inside I bolt it very tightly.

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Then I modded the battery cover, so the strut fits.

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Sporting some R3v pride.