Bushed Differential Mounting

[Jimbob]

Hi. I've just started building my roadster (first post), my chassis roughtly looks like it does on page 39. So early days but still very exciting.

I've decided to deviate on a few things from the book:

Rover V8 + LT77 (modified tunnel I know)

Modified BMW E30 front struts for front uprights

For the rear axle:
BMW E30 diff, axles, hubs (heavily modified for uprights, basically just the caliper and bearing carrier with the mountings welded on)


Other than that it's all going to be as close to the book as the bits I've specified above will allow. Anyway that's a picture of what I'm intending. I'd be interested to know what any of you think of my modifications. Especially the V8. I havn't yet found anyone else doing this...though I'm sure you're out there somewhere...

There is however, one thing that's been bugging me a load. Why isn't the diff mounted on rubbers???

It wont be EASY to mount the BMW diff on rubber, but is it worth it?

You get 1)reduction in noise, 2)reduced stress on transmission 3)reduced stress on chassis (the bit adjacent to my spline)

Maybe Chris or someone can tell me why the decision was made to transfer the Sierra diff from mounted on rubber via the subframe to a solid lump.

Presumably the stesses arn't too great, I don't know. It can't hurt though.


Good building.

James

Hi James and welcome!

The diff isn't rubber mounted because it doesn't need to be. In the Sierra the diff subframe is mounted in rubber for NVH reasons, not really a consideration in an open sportscar. In such a light car as the Roadster solid mounting removes any play from the drive system, rubber mounts would be under a lot of stress in the more demanding situation (standing starts and more vigorous aceleration).

Having said that there's no real reason not to incorporate rubber mounts if you want to, it's just that you wouldn't notice the advantages in a Roadster and they'd be something that you'd have to keep your eye on from a maintainance point of view.

Cheers

Chris