What diff with S50 + G240?

[khnordeen]

Hello r3v,

I am getting everything ready to swap an S50 into my 318i and am planning on keeping my Getrag 240. I have an M20 clutch/flywheel on the way, but am looking at the possibility of swapping out the 4.10 diff for something else.

My brother just had me bring home a 95 M3 that he just bought, and I loved the feel and the gearing to me seemed pretty much perfect for the kind of driving I will be doing.

What diff do you guys recommend to get something similar to that? Or maybe any other suggestions as well...

I apologize if this is a noobish questions, but from most of the threads I have read most people swapping in S50's tend to keep either the ZF or Getrag 260.

Thanks

[e30s50dan]

S50+G240+3.73lsd=me

[Wh33lhop]

I'd say the 3.73 would be a decent match. I wouldn't want to go any shorter than that with my M50, if I had an S50 I might go a bit taller honestly, maybe a 3.46 or so (especially with the slightly shorter .83 G240 fifth gear).

[StereoInstaller1]

240 has just about exactly the same internal ratios as a 260

[e30e]

95 m3 has 3.15 I believe, I know 96+ has 3.23. I've been in a 3.46 e30 or close gearing and 5th was a little buzzy at 80, but I'm picky.

[2002maniac]

I'd say 3.73 as well.

[StereoInstaller1]

95 m3 has 3.15 I believe, I know 96+ has 3.23. I've been in a 3.46 e30 or close gearing and 5th was a little buzzy at 80, but I'm picky.

Irrelevant as that ZF has radically different ratios...not so picky about math, huh?

[MR 325]

3.73 is perfect for your setup.

[Wh33lhop]

240 has just about exactly the same internal ratios as a 260

Nope. The 240's 2-3-4 is a bit closer. I thought 5th was .83 on the G240 as well but it looks like I was mistaken:

http://e30world.com/specifications/BMW-E30-specs-table

[StereoInstaller1]

What part of "just about" did you miss, bucko?

[Wh33lhop]

What part of "just about" did you miss, bucko?

What may look like numerically "just about" can actually make a significant difference in gear spacing. For instance, 3rd and 4th are 20% closer (1.32 and 1 vs. 1.40 and 1) in the 240. May not sound like a whole lot but it makes a sizable difference. That's the difference between a G260 and a dogleg close ratio 265/5.

Just sayin'. ;)

[StereoInstaller1]

oh I know, but that isn't gonna do diddly on the freeway. If it did I would totally rock the 240!

[daniel]

3.46 or 3.73 fo sho

[Mossman]

I have experience with S52, G260, and 3.73. Nice overall, a little buzzy on the highway but revs are the same as stock obviously and the 24v is smoother. It just has enough torque that it doesn't need to be revving so high. So I just threw a 3.15 in it. I like it, definitely lost acceleration but also makes it a lot easier to keep traction in 1st and on 1-2 shift. And much more relaxed on highway, approx 2mpg difference on highway, although I rarely drive a whole tank purely highway so that's not good science. Sometimes I have to downshift to 4th to pass when highway is moving slow, whereas 5th had passing power down to 50ish with the 3.73. That's the only inconvenience really.