Ideas for a 3.55 diff

[stevema]

Hi

I'm building a project Triumph Spitfire with the F20 engine & 6 speed gearbox from the S2000.

I can't use the spoon's diff as it's too low at 4.11 so looking for something around 3.55:1. It has to be able to take the 240 horses kicked out by the F20 and be available second hand in the UK.

Any ideas for donors?

Thanks
Steve

[one eyed mick]

Seirra can give you 3.14 to 3.9? and optional ratios from quaiff etc they will take cosworth power so should do the job ok lsd's too

[cmsapms]

Ford Sierra or Granada. Comes in two widths: 7 and 7.5 inch. Readily available in 3.62 ratio. Can be had with a viscous LSD as standard (from a 4x4 model). Various plate and ATB LSDs are available. The default diff for IRS equipped Lotus Seven-a-likes. Will laugh at your 240bhp! Also cheap!

[stevema]

thank you very much guys, found this beauty already.. not cheap but being rebuilt it should save hassles once installed

http://www.ebay.co.uk/itm/Ford-Sierra-7-LSD-diff-a...

[stevieturbo]

It looks nice...but it aint cheap !

A complete rear axle should run you £200 or so, that's with shafts and all.

[stevema]

stevieturbo said:

A complete rear axle should run you £200 or so, that's with shafts and all.

For an LSD in good nick? thanks

[stevieturbo]

stevema said:

For an LSD in good nick? thanks

The 7" LSD is fitted to ANY 4wd Sierra or Granada. 2.0 versions might have had the 3.9 ratio though.
And ANY does mean Cosworth variants too, as well as XR4x4 etc

The 7.5" LSD was only fitted to the 2wd Cosworths. A 7.5" diff was fitted to V6 Granadas, but as far as I am aware, none of them was an LSD, not even the Granada Cosworth.

Often a bog standard XR4x4 is the better diff to get as the cars will have had an easier life than a Cosworth variant, and Cosworths would carry a premium for no reason.

The standard viscous coupling in them all though is pretty crap. So consider that before paying a fortune for one.

Buying a cheap normal open diff/casing and a spending the money on a proper LSD might make a lot more sense.

But at least buying a complete rear axle jets you shafts, joints, brakes etc. If you need any of these.
Again, between the variants, there are different sized flanges, Lobros and shafts