M-Roadster swap

[racepad]

Hi,

I have an entire rear end from a 2000 M Roadster from the Diff to the brake rotors. I would like to swap this into the car with a future M3 engine swap in mind. Has anyone mated up this Diff to the existing drive shaft?

David

[Silver00spike]

make sure it has the same number of bolts

[racepad]

I presume you are referring to the flang on the Differential (6 vs. 4)?

[96cali]

To answer your Q a member named J!m did just what you are suggesting a couple years back. I have not seen him post in many months though. Very knowledgable but time crunched. Email him and see if he can give a few tips.

BTW how did you find an M rear and how much did you pay?

[cali-ti]

people have swapped the e30 LSD into an m-coupe/roadster so i can't imagine that it's not a 4-bolt diff/driveshaft flange on the front of the m-roadster diff.

the ti parking brake cables won't work from what i remember of others' posts. i'd put in poly subframe bushings while you're doing it too.

[racepad]

Hi,

Thanks for the tip on the ebrake cables. It is tedious but I know what to do there. The M-roadster diff has a 6 bolt flange for the drive shaft.

[cali-ti]

hmmmm ... so i guess you'd need to either change the flange or the driveshaft. yuck.

that said, if/when you get it swapped, it would be great to have a notebook article on the swap of the complete m-roadster/coupe rear (including e-brake changes, hydraulic brake lines, etc). i still need to put one together for the e30 LSD swap.

[racepad]

there is a decent writeup in the notebook section on the E30 diff and what to do there. Yeah, it looks like I will either have to find a drive shaft or change the flange to use this diff.

Got the setup from The Euro Depot (www.theeurodepot.com) in Concord, NH. These rarely come up for sale. They cut me a good deal and can't share the exact price. They are straight up guys and stand behind the parts they sell (new or used). A good source to check out when you are looking for parts. Enough on the plug ;-)

I will keep track of the project and post in the notebook and my web site as it comes along. It will be a while before I do this as I need to figure out what will work and there is little to go on here.

[cali-ti]

there is a decent writeup in the notebook section on the E30 diff and what to do there.
i ran into a number of issues when doing the swap (in fact, i think i found every possible problem!) so i wanted to provide more info regarding the swap, tools i used, etc.

[KIRASIR]

You just need to swap the flange (the driveshaft from 2.8l / M car won't fit your ti).

there is a decent writeup in the notebook section on the E30 diff and what to do there. Yeah, it looks like I will either have to find a drive shaft or change the flange to use this diff.

Got the setup from The Euro Depot (www.theeurodepot.com (http://www.theeurodepot.com)) in Concord, NH. These rarely come up for sale. They cut me a good deal and can't share the exact price. They are straight up guys and stand behind the parts they sell (new or used). A good source to check out when you are looking for parts. Enough on the plug ;-)

I will keep track of the project and post in the notebook and my web site as it comes along. It will be a while before I do this as I need to figure out what will work and there is little to go on here.

[racepad]

What flange to use? part number or from what other car/diff? thanks.

[cali-ti]

i'll tell ya too, i was looking to refresh the front flange seal on my e30 diff and when i looked at what it was going to take to get it off, i said "forget it!" that nut has to be torqued VERY HIGH. you'll need to rig something up to even get it off. i have pics of what i was going to TRY to use to get it off (let me know if you want to see them). i don't think my torque wrench even went high enough (or it was near its limit).

[racepad]

Fortunately I have a high torque impact gun that should take it off. I also have a torque wrench that will go up up high enough. Worse case I have some friends in the the area that can do this if I can't. Just need to identify the right flange to use.

[cali-ti]

the trick is finding a way to keep it from turning as you take the nut off. my idea for doing that is what i have pics of.

[racepad]

Did a lot of surfing and found this picture

http://www.unofficialbmw.com/images//new346-23.jpg

I thought it was odd that the six holes on the input flange were not evenly spaced. Here is a pic of the roadster diff and one can see that despite six holes only 4 are used. This potentially a great break through which woudl mean that the roadster diff might just bolt right up to the existing drive shaft. I plan on jacking up the 318ti this weekend to take a look and see what's there now.

[cali-ti]

Did a lot of surfing and found this picture
http://www.unofficialbmw.com/images//new346-23.jpg
I thought it was odd that the six holes on the input flange were not evenly spaced. Here is a pic of the roadster diff and one can see that despite six holes only 4 are used. This potentially a great break through which woudl mean that the roadster diff might just bolt right up to the existing drive shaft. I plan on jacking up the 318ti this weekend to take a look and see what's there now.
ok, that sounds better :) they would have to be evenly spaced around the perimeter. are all six the same size? i was pretty sure it was a 4-hole just like ours. btw, the nuts used to attach the driveshaft to the diff flange are a ONE TIME USE item, so get a set of new ones. use the old ones when you're getting the new diff into place on the driveshaft and then swap in the new ones when you're ready to do your final attachment/torque-to-spec.

[racepad]

Agreed. I turn the wrench on my race car so I know about the 1 time use nuts. Thanks for bringing it up though.

[cali-ti]

what do you race? i'm assuming it's the pic of the e36 in your avatar, but i can't tell from the front what model it is. what form of racing do you do, class, etc?

[racepad]

You can go to the racing section at http://www.racepad.com. The web site is still under migration and upadate so not all parts are up again. Next year I hope to get out to a few more races. The car is way underpowed for the class I race in but I still have lots of fun.

[cali-ti]

awesome! i need to get into some form of racing :( but big projects for this coming year will be buying a house, moving, upgrades to car ...