looking for a very short diff...

[darkcat]

Afternoon all.

Im just designing a project car at the moment, and in order to get the drive to the front wheels i need a diff with a very short input shaft. IE the distance from the end of the input shaft flange to the centre plane of the outputs to be as close as possible.

Everything i can find on ebay (for example) is quite long, eg 10"+ for the MX5 diff

It only needs to cope with about 120BHP / 100 torques.

To give you more of an idea what i need to do, im trying to wedge a Honda V-twin engine into a Mini, so the engine goes just behind the grill, and leaves a very short gap between the transmission output and the driveshaft plane.
There are other ways to do this, but this is the simplest solution...

Anyone got any ideas what is available (2nd hand) and it must be an LSD too...!

[PaulKemp]

Sierra 4x4 front diff???
Now this depends on where the engine is, what orientation, transvers or inline and where your taking the output from.
If your running an inline engine and running the drive forward then a rear drive diff would run drive in reverse

[darkcat]

I am going to mount the engine Morgan-style (but hidden).
The drive comes out of the gearbox just to the right (from the drivers perspective) of the crank.

Luckily the drive is in the correct direction (anti-clockwise, again from the driver's perspective) for the majority of diffs...

The only other option i can see is to bring a shaft from the drive output past a reversed diff, with a sprocket and chain to drive the diff from the other end (but LSD's may well not work in reverse)

[Cerbieherts]

PaulKemp said:

Sierra 4x4 front diff???
Now this depends on where the engine is, what orientation, transvers or inline and where your taking the output from.
If your running an inline engine and running the drive forward then a rear drive diff would run drive in reverse

Good call! That is a compact unit too!
A standard LSD wouldn't normally work if run in reverse as you'd be applying the load the wrong way through the plates. Maybe find a compact diff unit and contact someone like quaife?

[darkcat]

Cerbieherts said:

PaulKemp said:

Sierra 4x4 front diff???
Now this depends on where the engine is, what orientation, transvers or inline and where your taking the output from.
If your running an inline engine and running the drive forward then a rear drive diff would run drive in reverse

Good call! That is a compact unit too!
A standard LSD wouldn't normally work if run in reverse as you'd be applying the load the wrong way through the plates. Maybe find a compact diff unit and contact someone like quaife?

Hmm doesn't actually look any shorter than most other diffs... or am i missing something?

A front diff, however should be ok for my other method, as it will be working in its normal direction...

Yeah i briefly considered contacting Quaife, but quickly realised they are WAY out of my budget.

Edited by darkcat on Thursday 13th September 15:44

[Cerbieherts]

It's pretty short, not quite half the length of the sump, and it's not very wide either. I'm afraid I don't know the exact dimensions, but may well be worth your while looking into it. Interesting sounding project, by the way..

[stevieturbo]

Not 100% sure if the front diff on a Cossie is LSD. If it is it will just be a crappy viscous coupling.

But despite that, it wont care which direction it turns, so would be a viable option.

Or perhaps some 4x4 jeep's ?

[davepoth]

I think I found something that might work.



That's the rear diff from an 03-10 Fiat Panda 4x4, and IIRC certain years came with a mechanical locking rear diff.