Hi, questions for the "Locoster Fountain of Knowledge". Sure that somebody will have the answer! Which Bimmer is fitted with the 3.2(something) diff? Does anybody have a detail drawing of one with sizes? Has anybody changed a Sierra diff, (bolt on shafts), for the Bimmer one, and what work is involved? Many thanks, Ray

Simon was going to put one in as part of his turbo upgrade, I think it was an X5 job, something like 2.9:1 ratio.

Should be worth pinging him.

Regards Mark

Hi Mark, the 2.9 one would give me a supposed top speed of 190 MPH, so a bit on the high side. The 3.2? would give 2600 RPM at 70 MPH, so good economy, top speed of 160,(maybe). Cheers Ray

Hi Ray,

Some E30s were fitted with 3.25 and 3.23 diffs.

The list of diff ratios can be found on the E30 wikipedia page here:

link

Looks like they're only found on the less common variants, mind you. Also, I think the E30 diff is mounted quite differently to the Sierra one.

Jek

this any use? USA locoster who has used a diff, this page has a few pics of the mounts and the diff - they are pretty different from sierra!

http://www.locostusa.com/forums/viewtopic.php?f=35&t=1004&sid=6a64c2079a6365335b13c288bbc659bd&start=15

Morning

Yes, the plan is to stick a BMW diff in - the one I have is from a 330D with a ratio of 2.28 so very very low, but should make my gearing more useable.

My diff is slightly bigger than Sierra unit. I managed to get the appopriate drive shafts and will need to get them modified for Sierra outers. My shafts themselves have sliding joints in them, which is nice.

Unfortunately the turboing has gone on the backburner, but I still intend to use the diff. Just time unfortunately, haven't done a thing on car for three months now.

I'll try and get pic uploaded later

ATB

Simon

Hi Guys, thanks for the info. just what I was looking for. Would be nice to actually find somebody that had converted from Ford to BMW, but maybe I will have to be the first, :-) Cheers Ray

ATB

Simon

[Edited on 3/10/09 by Simon]

Wow! Simon thats some big lump, do you know the weight difference to the Sierra one? Cheers Ray

A BMW 525e (has to be the "e" variant" has a 2.93:1. Thats the E28 shape, 84-88-ish

528i has a 3.25:1 of the same vintage

quote:

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Originally posted by Chippy
Wow! Simon thats some big lump, do you know the weight difference to the Sierra one? Cheers Ray

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Simon my Sierra diff has the bolt on shafts, which I understand are the same as the Bimmer's, 100mm dia. with six bolt fixing. Regards Ray

Right, very approximately, the outer faces of drive flanges and prop flange to centreline of drive flanges are both about 29cm. So quite "square"

Will try and measure drive flange holes tomorrow - forgot, oops

ATB

Simon