Diff options

[Eljosh]

Hey guys,
I just did a auto to manual swap, and I have the 4.10 LSD in my car now. And I think it makes the car rev pretty high in the first and second gears. What options do I have to make it better? I heard that the 3.73 is a good option, but I see all kinds of diffs in the for sale, like 3.25 and 3.93. What kind of benefits would I get or not get from those? Oh I got the Getrag 260.
Thaks

[Wanganstyle]

Hey guys,
I just did a auto to manual swap, and I have the 4.10 LSD in my car now. And I think it makes the car rev pretty high in the first and second gears. What options do I have to make it better? I heard that the 3.73 is a good option, but I see all kinds of diffs in the for sale, like 3.25 and 3.93. What kind of benefits would I get or not get from those? Oh I got the Getrag 260.
Thaks

3.73 is the "best" option for m20b25+g260 transmission as it is factory bmw setting

4.10 is commonly choosen sporty option as 3.91 is not very common to find for e30 application in usa

Usually sporty settings increase the number a slight bit for street cars- bmw uses a 3.23 in e36 m3 compared to 2.93 in e36 328i. Both share the same zf sg320 5 speed gearbox but the m3 is obviously more sport intention than the 328 (luxury cruiser)

If you have 4.10 currently and want the best all round compromise then 3.73 will be the best choice.
If you are hunting for fuel economy then 3.64 would be a step down in cruising rpm's : rate of acceleration would also decrease.

3.46 is used with g260 gearbox and the larger displacement m30b34 and b35 engines: in e28e34 535i manual cars- m20b25 will be a bit sluggish with it as its 1000cc smaller.


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[MR 325]

I agree that the 3.73 is the perfect gearing for a B25/260 car. BMW got that one right!

[M44schnell]

After having a 2.93LSD in my b25 and going to a 3.73LSD with my 2.7i the 3.73 is a great all arounder, 1st feels crazy short compared to the old diff but i love my 3.73

[Herr Faust Schinken]

I think 1st is a tad to short on my Is and 5tg could be a bit longer but I'm really not picking here the 373 is great for a stock m20s power band but I think on a modified m20 an 3.64 would be just about perfect

[Wanganstyle]

I think 1st is a tad to short on my Is and 5tg could be a bit longer but I'm really not picking here the 373 is great for a stock m20s power band but I think on a modified m20 an 3.64 would be just about perfect

Yes 3, 64 I agree is nice to space out a little if power is increased

346 is good for high compression 2700cc m20 for street use as hardy and beck set the 327S with it standard. Would be a dog for bone stock m20 but good on fuel and flatlands

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[fronton]

Which is your priority- comfy cruising or zipping around? If equally important, 3.73 is your answer. It probably isn't worth the hassle to drop from 4.10 to 3.91 but would be to 3.73 or lower.