Right off 325 BMW

[Chris_]

Couldn't tell you in any major technical detail. but.

The four bolts hold it to the rear beam, the rear beam attaches to the body with some quite sturdy bushes, one at each end.
Although these are strong i think they would be wear out a lot quicker if it wasn't for the 'ear' which i have always just presumed is the main torque bearing structure. But actually looking at it a little closer, i reckon you might get away with just mounting it with the four bolts.
They are spread across a decent length, and are at two different seperation distances. I reckon it could take the loading ok.

Need someone clever to look at it i reckon.

Chris

[Chris_]

Mind you, (thinking again, always bad for me) when they run proper power in E30's the bodyshell where the rear cover bush (the 'ear') mounts does have a tendancy to rip away so it must take some fairly significant forces.

Hows about an E36 diff (not compact) these have a pair of 'ears' and are considered to be stronger. As well as more symetrical.

Chris

[Chris_]

Right i've been musing over this at work today, did some (very very) rough drawings and measureings.

I reckon, but dont quote me on it, The Diff is subjected to torque loadings on two axis - The longitudinal twist from the prop shaft/gearbox/engine. And the latitudinal twist from the road wheel friction (equal and opposite Blah de blah)
So the four main mount bolts hold the diff solidly to the rear beam which then opposes the torque of the prop shaft through the entire width of the beam and the butch mounts at each end (decent leverage, lower force)
The big ear at the back is a just a stabilising link. Friction from the tyre-road interface will try to oppose the driveing torque and force the rear of the diff off of it's centre line. It it didn't have the 'ear' it would be working on a lever about 18 inches to try and break the beam bushes. So they've thrown in this rear stabiliser.

So, Cut the ear off, solid mount the diff from two transverse box sections of of a pair off diaginal longitudinal box sections, job done.

I think they are M12's so get 8.8's and it 'should' be strong enough with the weight of a roadster

Cheers
Chris

[RAYLEE29]

Hi, looking at your picture the set up is v similar to the sierra and the ear mount is there to stop the diff/beam moving up/down.
if you were to fit it in the roadster chassis you can mount it using the four front bolts and do away with the rear mount as you will be mounting solidly direct to chassis not via a rubber mounted beam
Ray

[GraemeWebb]

See my flicker pics for what I am doing with my 4 cyl bmw build. Will post some pics of my front upright conversion soon.