WTB: Z3 M battery box

Whether you are having a garage clear-out, looking for a second-hand accessory, or buying/selling a Z, post your 'for sale' and 'wanted' ads here.
This Forum is not meant for discussion, please do not comment on the asking price.

Moderator: Gazza

Post Reply
User avatar
pinkpiggy
Joined: Thu 05 Nov, 2015 00:04
Posts: 39

  Z3 coupe 2.8

WTB: Z3 M battery box

Post by pinkpiggy » Sat 20 Aug, 2016 14:11

Hello guys,
because of my plan is "rebuild" my trunk on my coupe on m trunk (because of exhaust), i would like to buy battery box. I am located in Czech republic (post is probably only solution).

As well as battery box i would love to buy the toolbox as well (tools doesnt need to be included).

Thank you very much for offer.
BMW Z3 Coupe, M52B28, 2.8, Hellrot/black, sunroof

Image Image Image Image Image

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Thu 01 Sep, 2016 19:18

May i ask...
Whats the difference between the non M Trunk and the M Trunk that makes a need in this battery box?
Thanks

User avatar
Devon Z
Z Register member
Joined: Thu 20 Nov, 2003 21:39
Posts: 650

  Z3 roadster 2.0
Location: Brixham, Devon

Re: WTB: Z3 M battery box

Post by Devon Z » Sat 03 Sep, 2016 12:50

With the twin exhaust on the M the battery box is in the middle of the boot floor instead of the right hand side as on non M cars.
99 Topaz Individual

User avatar
pinkpiggy
Joined: Thu 05 Nov, 2015 00:04
Posts: 39

  Z3 coupe 2.8

Re: WTB: Z3 M battery box

Post by pinkpiggy » Wed 07 Sep, 2016 14:25

Exactly how devon wrote, with M trunk the battery is located in the middle of the floor. That allows you to have duplex exhaust.
BMW Z3 Coupe, M52B28, 2.8, Hellrot/black, sunroof

Image Image Image Image Image

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Thu 08 Sep, 2016 15:55

I did a full twin exhaust conversion on my 2.8. I relocated the battery to the center, but didn't bother with the original M battery box because the boot floor of the M is also different to a non M car. The M version has specific contours for battery cabling and locating the various components. I had a panel shop cut out a hole in the floor and make a metal box to fit under the floor - all welded, painted etc etc... The original piece of floor where the battery used to be located was covered over with sheet metal and welded too. Next is you will need to remove the spare under the car, and cut away the brackets which the spare holding device hinges etc.. next, you will need to have exhaust mounting parts fitted on the right side to match the current left side pipes, and finally make a template of the bumper cutout on the left and make an identical cutout on the right side. The OEM M battery box fits into the M boot floor and finishes flush with the floor due to the floor being pressed at production to allow the fitting - Non M cars don't have that same floor... :wink:
"Normal is overrated"
Image

Z3 Upgrades and Additions

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Sat 10 Sep, 2016 13:16

Southernboy... im just about to go throgh the process myself... bought a complete set of M rear parts... so will need 4 mufflers...
Any photos of relocating the battery?
Thanks :)

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sat 10 Sep, 2016 14:39

First, you only need one more muffler - that's unless the existing one is shot. The Z3 system is a single pipe from the front header to the rear muffler, the muffler has 2 pipes extending out the back of it. I would suggest you speak to Spurs Fan / aka Andy about a spare OEM muffler - he's like able to help - or try eBay or the scrappies.

2nd - The battery box needs to be dead center - left / right, and far enough back that it won't interfere with the diff/ axle carrier under the boot floor. Place the battery on the floor centrally in position, and use a sharp tool to scribe a line around it on the boot floor - then increas the size of the rectangle by 1/2 inch all round. That's so you can get the battery into and out of the new box once it's in. Also, measure the battery from it's base to the tip of the terminals and add 1/2 inch to that measurement - that's so when the battery is in the box, the terminals are well below floor level.

3rd. Find someone to make the box, cut the floor and weld it into place. Also, the existing battery box will need to be cut out and a plate welded to complete the boot floor in it's place. A professional welder / sheet metal worker / autobody shop should be best used.

4th. whilst the person fitting the new box is doing his stuff, you may as well ask him to cut the spare wheel carrier and it's hinges away.

5th. you will now need to have a pro exhaust fitter make a new pipe for the right hand side system. This requires all the pipework from the front to the muffler. NB. Be sure the person making it is a professional. Both the left and right pipes need to be joined just aft of the 2 header pipes under the engine with an "X" system. This means that both left and right side pipes will carry exhaust gases irrespective of which of the 2 header pipes from their respective 3 cylinders is pushing gas out.
The reason for this is that if you don't do it this way, the exhaust sounds will alternate from left to right muffler as each handles only 3 of the 6 cylinders... not what you want !! you want a constant purr from all four pipes all the time - hence the "X" join at the front end of the system...

I did have some pics of my setup, and I have had a look for them - but oddly, I can't find them... If I do, I'll post them.

I had 55mm pipes running from the "X" through to the mufflers - I replaced the OEM muffler for a matching Stainless pair - Z3 spares in SA are like hen's teeth, hence my decision to have a matched pair. Obviously with Z3 parts being more common in the UK you should try for an OEM part first.
"Normal is overrated"
Image

Z3 Upgrades and Additions

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Sat 10 Sep, 2016 17:20

As usually- thanks alot!
Hope u can find some pics so i can show my man who going to work on the car.
Thanks!

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sat 10 Sep, 2016 19:18

Best I can find is below - you can just see the welded box and it's relative position to the diff.

Image

Image
"Normal is overrated"
Image

Z3 Upgrades and Additions

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sat 10 Sep, 2016 19:32

One point I omitted to mention - you will need a length of heavy duty copper wire aprox 700mm long and a splicer/connector to extend the positive battery cable and connect it to the existing positive supply cable. It is imortant to use the same type of cable which is made up of probably hundreds of very fine copper strands sheathed inside a heavy duty plastic sleeve. I used a brass connector which is commonly used in the welding trade to connect two pieces of such cable. I heated it with a small gas torch then shoved one end of the battery cable into one end, then used the gas torch to melt lead into the same entry point - then did the same at the other side, and finally fitted the connector which attaches to the positive terminal on the battery. You will need to route the cable from the positive terminal staight back towards the metal wall which forms the deepest recess of the boot, then towards the right and connect it to the OEM cable which then feeds to the front of the car / power distribution box etc.. The earth cable from the battery can be simply removed from it's OEM position, and moved into the welded box.
"Normal is overrated"
Image

Z3 Upgrades and Additions

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sat 10 Sep, 2016 19:42

I later on fitted a twin eared diff cover to avoid the dreaded boot weld popping issue, and you will see from the pic below, that some parts of the spare wheel carrier were removed to allow the new fitting. I had to manufacture a new mounting bracket for the right hand side ear of the diff....

Image


This was the original interior...
Image

and this is what I converted it to...

Image
"Normal is overrated"
Image

Z3 Upgrades and Additions

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Sat 10 Sep, 2016 21:03

Wow... and i tought i did some real job on my Zed... hehe
One more thing to ask... when relocating the battery to the middle... what did you do with the tools? Removed them, or just put the battery under that tools box?

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sat 10 Sep, 2016 21:25

I did away with the OEM tools. Bought a small compressor which plugs into the ciggy lighter, and a puncture repair kit for tubless tyres. A small set of socket spanners with 6mm to 14mm sockets, it also has a screwdriver and socket attacment to hold a Phillips or flat screwdriver bit in the kit, plus a mini ratchet and two extensions. All 8mm drive size. It is small as a kit in a steel box and I stored it in the small triangular recess behind the right tail light together with the puncture repair kit and a hand wipe cloth jammed in to stop things rattling about. The mini compressor I fitted to the underside at front of the passenger seat. Since I had to dump the spare wheel, for the extra exhaust, there wasn't much use for a jack. I also carried one of those "multi-tools" with the fold up pliers etc etc as part of it's kit. That lived in the storage box between the seats at back. Also the wheel security socket lived there too - the one for the wheelnut.... So basically I still carried tools, just in a different way....but no jack.
"Normal is overrated"
Image

Z3 Upgrades and Additions

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Sat 10 Sep, 2016 22:13

Ok... understood
Sometimes im thinking of being without the spare wheel and its kinda make me feel scared... for example... once i had a really big crack in the tire... what would you do without a spare wheel in that case?

User avatar
Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6312

  Z3 roadster 3.0i
Location: Johannesburg

Re: WTB: Z3 M battery box

Post by Southernboy » Sun 11 Sep, 2016 06:09

You will need a new tyre if that happens, so you would need to call an appropriate roadside assistance organisation like AA, or such.
"Normal is overrated"
Image

Z3 Upgrades and Additions

zz3po
Joined: Sun 30 Aug, 2015 10:31
Posts: 73

  Z3 roadster 1.8

Re: WTB: Z3 M battery box

Post by zz3po » Sun 11 Sep, 2016 14:08

Yep... :)

Post Reply

Who is online

Users browsing this forum: Gazza and 4 guests