Whats the best choice for rear diff?

We're using a Fireblade engine and have been told that we really need a limited slip and also that the best gearing for these engines is around 3.36:1

I've got a standard seirra diff which is 3.62:1 and not limited slip.

I've seen a re-con diff thats 3.36:1 but its not limited Slip.

I can get hold of cossie parts fairly easily but dispite being limited slip they are 3.64 (2wd) and 3.62 (4wd).

What do I go for without spending a fortune on a Quaffe?

What have others used?

I run a 3.89 with 15" wheels, try this link

http://www.customautotech.co.uk

go to downloads, load the "pulse per mile" its just summat to set the dash up, but if you put combinations in there you can work out what wil and won't work,

my set up comes out at 6500/mile, this gives me 120+ top speed and rapid acceleration.....hope this helps, Jon.

Cheers mate. I'm off to take a look.

So what sorta diff you got and is it an LSD?

Just got my self a 3.62 LSD thats what martin used in his indy blade.

Came from http://www.classicconversions.co.uk

Did a deal for me as i also got drive shafts and rear hubs at same time.

All stuff is full reconditioned to as new.

Hope this helps.

I'm glad he did a deal for you, Tony, because those price list prices for re-con diffs (£475 +VAT + postage for a 3.62 outright) seem pretty high to me

John

Yea they do sound a tad high to me aswell.

I've since decided that the 3.62 will do fine as I'm not worried about top end so I think what you have got will be ideal.

Thing is... A cossie diff is 3.62 and LSD and I can get these quite cheaply. So now another question.

If I used a cossie diff. Would I need to use the rear disk brakes and would I still be able to use the MK supplied rear hubs?

I thought Kit-Fit in Newark were pricey but a regular sierra diff in any ratio came out £190 before VAT.
They do LSD but i have no price 01636 893453.

All LSD diff use lobro type drive shafts, i.e ones off cars fitted with rear disks.

U can use the bearing carriers and hubs off of a rear disk car just tell martin as they make a different rear uprights for drum and disk fitment. The mounting holes are slightly differnet.

As to diffs from kit fit all they do is an inspection and change seals not a complete overhaul and there price or and LSD is around £250-300 +vat depending on ratio.

I will probably get the whole lot off the cossie then. Diff, shafts, stubs and brakes.

I've already got my MK rear hub carriers but I'm sure Martin will swap em over. Or is there any way of using drums on a cossie (or any lobro) diff/shafts?