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diff ratio
Posted: Sat Sep 20, 2008 10:14 am
by mackley
i've got a E30 320i which i'm using for oval racing but the problem i've got is 2nd gear is running out of steam to soon so i'm thinking of changing the diff. I was wondering which would be best to give me a longer 2nd gear and what would I get it out of. I have a few diffs but i've been told that the 325i diff may not bolt straight up to the existing shafts.
Can anybody advise me whats best ?
Re: diff ratio
Posted: Sat Sep 20, 2008 7:35 pm
by daimlerman
If you are using the fitted standard diff. you have a 4.1 small case.(6 bolts in the rear cover)BMW supplied a multitude of diffs,from 4.45 up to 3.25,in two case sizes.Both sizes will fit,if the diff has come from an E30 the prop shaft may need ajustment(slacken the large nut on the centre bearing and use a Birmingham spanner) If your diff comes out of an E28(you can find ratios as long as 3.05 this way)you may need to swap the output flanges.As two case sizes of diff are used,so there are two thicknesses of output flange,the thinner one's fit with the larger case.