Diffs again....

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canada karl
Posts: 599
Joined: Tue Jan 06, 2009 3:50 pm

Diffs again....

Post by canada karl » Tue Feb 26, 2019 12:02 pm

If I take out the diff(3:64)in my 76 530i with a 5 speed and put in a diff(3:45) from a 77 530i auto how does it change things in terms of losing or gaining acceleration and also gearing for highway cruising?
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car

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Mike W.
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Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Diffs again....

Post by Mike W. » Tue Feb 26, 2019 12:11 pm

You would lose a bit off the line, and at all speeds actually, and drop the revs 150 RPM or so at 100k. With a 4 speed I would want a 3.45, with the 5 speed I'd leave the 3.64 in place. Your speedo will also be off by 5.5%.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

canada karl
Posts: 599
Joined: Tue Jan 06, 2009 3:50 pm

Re: Diffs again....

Post by canada karl » Tue Feb 26, 2019 2:28 pm

Thanks Mike :)
1976 530i. BMW 59 Triumph TR3A(rolling resto). 67 Triumph TR4A(salvageable). 86 900S Winter car

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