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3.91 LSD and 4 speed?

Guest Anonymous

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Guest Anonymous

anyone run one of these? I think my 3.6 is on it's way out (metalic rattle

from the rear of the car, and a leak?) and I am thinking of moving to a

3.9...of course, I have a 4 speed. I almost never get on the highway

though, so speeds above 70 are rare for me. Am I crazy?

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Guest Anonymous

driving is a bit tiresome because of the high revs, but there is nothing wrong with the combination. The E21 5-speed conversion basically has the same gearing in 1-4 as the 4 speed.

John N

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Guest Anonymous

I have a 3.91 LSD and a 4 speed. It's a nice combo, but my

diff. is pretty noisy. If I replace it, I will probably go to a 3.64

LSD for two reasons. First, having owned other 02s with both

3.91s and 3.64s, I do appreciate the slight reduction in revs

at highway speeds. Second, I think the 3.64 might work a

little better for autocrossing because it allows you to hold

second gear a little longer--hopefully eliminating the need to

juggle between second and third frequently.

As far as wear and tear go, I'd imagine if there is any

increase with the 3.91, it's negligible.

Also, to clarify, the '76s were equiped with open 3.91 diffs;

none of which, as far as I know, had limited slips. So, you'll

have to get a differential from a 320i if you want to go with


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Guest Anonymous

the difference in noise between 4k and 3400 rpm is HUGE over long hauls- and there's a resonance in my car at 4kish anyhow...



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