Diff

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calex
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Post Thu Dec 20, 2012 3:25 pm

Found a diff in the scrapyard 3.46 will this be any use for my 325 m20? Cheers.
Speedtouch
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Post Thu Dec 20, 2012 3:27 pm

Probably, if it is a medium case one.

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///M aurice
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calex
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Post Thu Dec 20, 2012 3:35 pm

It's looks exact same as came out.
Speedtouch
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Post Thu Dec 20, 2012 3:51 pm

In that case, it should be fine. What do you currently have, 3.64 or 3.91?
///M aurice
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calex
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Post Thu Dec 20, 2012 5:53 pm

Not sure the tags missing and it was on the car when I got it, it was an lsd but the gears are in about 10 bits now.
Speedtouch
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Post Thu Dec 20, 2012 6:05 pm

Most 325i Sport LSDs were 3.91:1, and a bit low-geared tbh.
///M aurice
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Brianmoooore
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Post Thu Dec 20, 2012 8:09 pm

3.46 is an excellent choice of ratio for a M20B25, but if it' replacing a 3.91 you'll notice both a difference in acceleration (bad) and in your wallet (good).
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calex
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Post Sun Dec 23, 2012 2:14 pm

yeh i put the diff on yesterday and it perfect for that car. The only difference i noticed is in 5th the revs are at 2500rpm at 70mph, the last diff was about 3100rpm so it cruises nicer and bound to be better on fuel on a long run.
Andyboy
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Post Sun Dec 23, 2012 6:25 pm

That's a rare diff and it would have come from a 323i. A very similar 3.46 diff is fitted to 24v E34 520i's. Swap the rear cover and flanges and it swaps straight over.
bss325i
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Post Sun Dec 23, 2012 8:02 pm

The 320iS also used a 3.46.
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