Lightweight LSD required - advice please

[InMyShed]

I would like a light-weight limited slip diff, does anyone have some advice on which way to go? The car will be running on 13" wheels and will be powered by a 170bhp engine reving to about 11,000. Would an MX5 diff be any good? Do you know the weight of one?

>> Edited by InMyShed on Wednesday 26th October 16:02

[Incorrigible]

I'm looking for something similar myself

The speed the engine revs at isn't that important (as the gearbox can vary drastically) but you'll need to know how much torque you intend to put through it

Best one I've found so far is the freelander one with uprated internals (quaife)

I assume it's IRS not a live axle or anything odd

[Munter]

The Torsen fitted to the 1.8 MX5 will take quite a bit of punishment. People are running more than 200bhp/200ftlb through them. (Avoid any 1.6 MX5 diffs for real power).

[deltafox]

Torque biasing diff as fitted to the Focus rs 220?

[grahambell]

Judging by the revs I assume it's a bike engine.

In that case would a Quaife chain drive diff with reverse as used by Radical be any use?

If so I just happen to have one available.

[cptsideways]

MX5 one like the one I have in my shed?

Just like this



Weight with the complete frame/support is about 25kg's diff only about 15kg's.

A 1.6 one is lighter, by quite a bit & will easily handle the torque from a bike engine. I've run 180-200bhp through one with some really serious abuse all year, only issues were driveshafts & that was my fault.

If you need an LSD I have one sat right here

[Munter]

cptsideways said:

MX5 one like the one I have in my shed? [pic woz ere] Weight with the complete frame/support is about 25kg's diff only about 15kg's. A 1.6 one is lighter, by quite a bit & will easily handle the torque from a bike engine. I've run 180-200bhp through one with some really serious abuse all year, only issues were driveshafts & that was my fault. If you need an LSD I have one sat right here

Is that a 1.8 torsen cptsideways or a 1.6 viscous. If thats a 1.8 torsen and your looking to shift it drop me a PM with a price.

[dern]

Are these a lot lighter than a sierra xr4x4 diff?

Mark

[Incorrigible]

dern said:

Are these a lot lighter than a sierra xr4x4 diff? Mark

If the 15kg quoted by Cpt sideways is anywhere near accurate then by loads

[dern]

Incorrigible said:

dern said: Are these a lot lighter than a sierra xr4x4 diff? Mark If the 15kg quoted by Cpt sideways is anywhere near accurate then by loads

Buggrit... and I've just welded in the diff support

[Incorrigible]

dern said:

Buggrit... and I've just welded in the diff support

Best get the slim fast out then

[Frik]

deltafox said:

Torque biasing diff as fitted to the Focus rs 220?

Quaife ATB diff is not exactly light IMO.

[d-man]

I don't have much direct experience of BECs, but wouldn't a standard MX5 LSD have too short a ratio? They're 3.9:1 or 4.1:1 I think, compared to the Sierra or Freelander diffs at around 3.2 - 3.6:1 that most BECs seem to use. Might end up bouncing off the rev limiter in top if you're not careful.

[dern]

Incorrigible said:

dern said: Buggrit... and I've just welded in the diff support Best get the slim fast out then

Hang on... how dare you!

[InMyShed]

Do all 1.8 Mazda MX5s have a LSD? If so, are they all the same type?

[robbieduncan]

InMyShed said:

Do all 1.8 Mazda MX5s have a LSD? If so, are they all the same type?

As you can see here: www.mx-5.org/oxford/guide_mx5.htm Not all 1.8s have an LSD. Some special editions do and the recent 1.8iS models do.