Sierra diff

[Burts motorsport]

Hi looking to see what ratio diff I need its for a sierra just got a straight cut gear kit for my type 9 box ratios are as follows
1st 2.20
2nd 1.69
3rd 1.21
4th 1.1
5th 0.93
what ratio diff do I need? Want it for acceleration more than top end! Cheers

[Graham]

sierra diffs did not come from ford with a low enough ratio, the most commonly found lowest one was 3.6 iirc, which is too tall for max acceration, but 4.1 and 4.4 were made in the aftermarket to suit westfields, i would try westfield forums or suppliers for kit car parts

[ugg10]

There was a 3.9 Sierra diff as well as stock but this was not lsd. 3.6 was open and led and 3.38 was open iirc. The 3.38 is liked by the bike engine locost boys.

Full list on here http://www.super7thheaven.co.uk/comp..._differential/

[Burts motorsport]

Cheers mate I'll give that a go

[ugg10]

Couple of 3.92

http://www.ebay.co.uk/itm/7-Ford-Sie...MAAOSwMtxXriST


http://www.ebay.co.uk/itm/ford-sierr...sAAOSwBmZWCnqy


And a 4.27 with bolt on shafts, larger 75.5" Granada though if that makes a difference

http://www.ebay.co.uk/itm/ford-sierr...MAAOSw9r1WCnm7

You can also use the speed calculator on here to see what speed they are in gear - http://www.subarugears.com/Ratios/Ratios.html

[Frits]

The 4.27 diff of a scorpio will fit the Sierra rear beam with some modification. The bolt-on flanges on the 7.5" diff can be removed and the Sierra half shafts will fit in Without a problem😃