E36 BMW M3 Diff on cossie beam?

[Chip]

Originally Posted by pacwest I'm a big fan of the supra diff. I've seen it done too many times with excellent results to look at anything else. They certainly seem to run massive power on them on the standard diff more than anyone on here is likely to need (well other than maybe rod!)

If you were logged in, you wouldn't be seeing this ad! Register your free account today, or log in if you already have an account.

[worked_xr]

I know this is an old thread, but I found it while doing another search, so I thought I'd post. I've got an E36 LSD diff in my XR4TI... no custom halfshafts required, no custom driveshaft adapter required. It just requires some mounting brackets and a diff mount. Pics:

[Ben M]

Originally Posted by worked_xr

I know this is an old thread, but I found it while doing another search, so I thought I'd post. I've got an E36 LSD diff in my XR4TI... no custom halfshafts required, no custom driveshaft adapter required. It just requires some mounting brackets and a diff mount. Pics:

do you know what e36 it came from as im sure theres a few different types ?

good work though and looks a fairly straight forward job

[worked_xr]

Originally Posted by Ben M

do you know what e36 it came from as im sure theres a few different types ?

good work though and looks a fairly straight forward job

My diff is from a 325i. Actually, I have two 325i diffs... one has a 3,15 ratio, the other has a 3,90 ratio. My diff install was actually developed by fellow XR4TI owner in Seattle (not John V.) and he's been running a 3,90 ratio E36 325 diff in his daily driven XR for several years now, doing drift and other driving events, and it works great.

[lee2cossies]

Excellent pics been hopeing someone would put some pics up as im really interested in doing this to my car.If its pretty simple im going to find one and have a play about.Just have to do a bit of research on the ratios.

[worked_xr]

You do have to modify the diff casing a bit... cut off the stock mounting ears, a little grinding, but there is plenty of metal to work with. As for ratios, there are lots, and it's my understanding that E30 gears fit the E36 LSD diffs, so that provides lots of ratio options.

[MalteseFalcon]

Hi there, It's true that in Malta there is about 3 sierras which I know that have done this modifcation. Now I have just bought a BMW E36 diff with a 3.9 ratio from UK and we are waiting for it to be delivered. It cost 725 GBP till now but it will be a great modifcation as the ford unit is not strong. Some people may think that a ford 9" is strong but is not. One of the Sierras which is an RS500 had 1st a 7.5" with a qaife LSD but all the time was breaking the CWP, then he bought a FORD 9" and he break it as well. Now he fitted the BMW diff and is doing a 1.5 60feet in the Drag strip in Malta which is pretty good. When he fitted it at first he had a 3.2 ratio but this coused breaking the T5 then after changed the CWP to 4.1 and the Sierra is doing 10's. They told us that it would require few modifcations to fit as the shafts has the same flange only it would be a bit short on one of the shafts and a spacer is required. and the prop shaft it would need the yoke of the bmw to fit to the ford shaft. I will take some pics on the process to show you how we are doing it

[TWoods]

I fitted few bmw diffs to things like Dolomites, Stags, mk 1+2 Escorts and Cortinas its a parts bin heaven, pre 95 bmw diffs are plated generally after 95 used torsen type to go with abs, tc in all bmws variations which allows variable and gradual lock up but never fully locks as per earlier plated diffs.

From early big 5 and 7 series the diffs for 3.0l+ M cars rated to 1000nm iirc but doesnt like big revs overheats the oil needing external coolers, the bigger oil volume with cooler to cope the M diffs already have provision for take-offs as standard. The 80-90's 3 series diffs have small or medium case diffs not much is interchangable inc half shafts medium cases will cope with 500nm and lots of revs, small case will cry and whine like a bitch until it mashes its cwp at sight of 300nm.

[worked_xr]

We chose to use the BMW diff setup because it is a reasonably priced way to get a limited slip diff for our cars. We do not have easy access to stock Sierra 7,5 LSDs and importing them makes them extremely expensive for what you get. A Quaiffe setup is prohibitively expensive for most of us as well.

By comparison, I'm surprised at some of the costs being quoted for BMW diffs in the UK. Our diffs here have been purchased used, for $50US to $150US. No rebuilding, no new clutches... just fresh fluid with a good LSD additive and installed. Our cars are making 375-400nm and the diffs don't have any problem with it at all.

JVAB's Supra setup was not completed at the time that we installed the BMW diffs... I was in fact waiting for John to finish it up, but had the opportunity to do the BMW diff very inexpensively, so I did. I think the Supra diff conversion (which is now available from JVAB, including mounting, halfshaft adapters, beam reinforcement kit, etc.) would be an awesome choice.

Also, another US guy is selling kits to install GM positraction units into the stock 7,5 diff. It is very reasonably priced, but it leaves you with the 7,5 diff and limited ratio choices (in the US we only have a 3.36 or a 3.64 available). Not ideal, but it is cheap and fairly easy.

[dom123]

such a good thread.. i think all us 2wd cossie owners need to work together to find the cure to the weak diff problem!!

[Mark V8]

8.8 inch Ford in Sierra



http://home.comcast.net/~xr4x4ti/V8_AWD_Pictures.htm

Mark

[worked_xr]

Also a semi-popular option in the US. Cheap, easy to find, lots of ratios.

[TWoods]

Originally Posted by worked_xr

Also a semi-popular option in the US. Cheap, easy to find, lots of ratios.

UK diffs bloody expensive even for open ones, I buy them from other countries in EU even with shipping still much cheaper than buying local. The BMW diffs easy to mix n match with jap stuff there is alot of similarities, you can even buy factory choke kit for £270 to uprate standard 25% to 40%-70% lock up, new lsd plates are cheap too.

[lee2cossies]

Some really good info,keep it comeing.

[worked_xr]

Here's some more info on my E36 diff install...

1. I'm using a regular E36 (non-M3) diff. I believe the M3 diff case has some differences, but I'm not sure what they are.

2. It did not require a custom prop shaft (driveshaft). There are two different E36 diff input flanges. One flange type is "square" with holes at the corners for bolting on the BMW prop shaft. The other flange type is "round", which is the one we used. It simply required turning down the center a bit and rotating the round flange 45 degrees and drilling new holes to match the stock prop shaft bolt pattern.

3. It was not necessary to use custom halfshafts (axles) either. The bolt pattern of the axle flanges matched the stock axles, however the BMW diff's holes are tapped for M10 and the Merkur requires M8. The solution was to get some M8 helicoils and thread them into the M10 bolt holes on the diff's axle flanges and bolt up the stock halfshafts. Problem solved, and it has served flawlessly.

4. Getting the diff in the right position is essential if planning to use the stock halfshafts. The alternative is to bias it to the long halfshaft side and use two long halfshafts instead of one long and one short.

5. I could probably get the guy who did my diff to post up if you would like to ask him specific questions. He's recently built an XR4TI rally car as well with 4.10 BMW diff, so that's three diff installs he's done. He also developed a beam reinforcement kit that is now available very cheap through JVAB.