B2 90 2.3q diff fit a 3b s2

[woodwoody]

Can anybody tell me if the rear diff off a 90 B2 Quattro that was 5 cylinder will fit my s2 3b as it needs replacing and I have the 90 one lying about

[quattrodave]

My understanding is that the B2 rear subframe uses different (earlier type) rear track arms and there are no anti roll bar mounts welded on subframe (unless its a very early ur subframe).

[speeding-g60]

he sounds like he is asking about the diff itself.

if so, yes they should although the output flanges will probably be different sizes. you can swap them out.

[quattrito]

What about ratios? I think B2Q diff won't go on S2. But I could be wrong. Even the mounts are different type. I think that wouldn't be the best solution.

[woodwoody]

Will the v6 80 coupe ones be the same then? Just looking for a option as s2 diffs seem to be less easy to find here?

[quattrodave]

Oops my mistake, S2 and 20v B3s have different ratio to V6 diffs which are from B4s (well in the UK) 4.11 in 5 cyl cars compared to 3.89 in 6 cylinder cars from memory. I know when my dad brke the gearbox in his B3 10v audi 90 quattro I swaped the box and diff with one from a V6 I had lying around (hens teeth these days) and it ******ed the characteristics of the car as the ratios were a bit longer so it was doing say around 24 at 1000 revs as opposed to 22 previously so the acceleration was crap and you had to use 4th more around town.

Again from memory but you will need to check I think the UR also had 3.89 but the B2 coupe quattro uses 4.11, obviously the tyres make a difference as B2 used 14 inch wheels, I recall our B2 coupe was geared for around 122 mph at 6000 (same as B3 audi 90 quattro) whereas the B3 coupe with the same final drive comes in at around 130 (bigger wheels) and the V6 with same size wheels as the B3 coupe pulls around 138 at 6000 due to the change in ratio.

So from memory B2 coupe quattro = 4.11 same as S2 but check it out !

[_ShurikeN]

5cylinder B2 diff would fit S2 coupe exept flanges diameter (100 vs 108mm). Flanges may be swappable. Have not tried that myself, but it was told that. Worth a try.
Both diffs must be 4.11. S2 diff case has detachable mountings, B2 one is solid, but they should be identical in terms of mounting on a subframe.

... and there are also some 5cyl B2 diffs in ETKA which are said to have 108 flanges. And maybe they are UrQuattro-only diffs, I didn't manage to find out.

[Val]

Later B2 also had diffs like B3.
V6 could be 35/9 ratio. Check it before buying that.

[woodwoody]

Cheers guys