Rear Gears

[FredK]

Around 2500 rpm with a 3.25, 2250 with a 2.93. A G240 has an overdrive 5th.

[Wh33lhop]

At 65, if you were turning over 3500 before with a 3.73, you're looking at 3050 with the 3.25 and 2750 with the 2.93.

However your numbers do not seem in line with a stock tranny and 3.73 rear end.

[FredK]

Um, yeah, I should have used proportions rather than a gear calculator. Oops. :D

[threlevenguy]

Right on, 2.93 sounds good. That second ebay link that I posted -- That bolts right up with that case correct?

[Wh33lhop]

Right on, 2.93 sounds good. That second ebay link that I posted -- That bolts right up with that case correct?

It should.

If I were you I'd take a gander at my rear end though (no homo), doesn't sound like you're running a 3.73. Sounds more like a 4.45.

[NC325iC]

2.93 would be good for highway cruising but your gonna loose some of the fun acceleration

[threlevenguy]

Hmm...I gota have some fun. The 2.93 isn't fun at all?

[rThor432]

I have a 2.93 in my car it is still quick, but I wouldnt mind having a bit more gear back there. All I do now is highway driving, so it makes sense. I average ~32-33 mpg. The 3.25 would be easy to find and ideal for mixed driving.

[threlevenguy]

What did the 3.25 come in?

[Wh33lhop]

I have a 2.93 in my car it is still quick, but I wouldnt mind having a bit more gear back there. All I do now is highway driving, so it makes sense. I average ~32-33 mpg. The 3.25 would be easy to find and ideal for mixed driving.

Which engine and tranny are you running though? If you're running an E36 transmission a 2.93 would be fine, but with a G260 or G240 with a .81 5th gear it's going to be very tall.

I'm still not convinced the OP is running a 3.73.

[Rigmaster]

3.25 is about the only commonly available diff that will bolt in (found in several different E28's). Most people say a 3.46 or 3.64 is ideal, but they're really hard to find in an E30 case.

What did the 3.25 come in?

No offense, but most of the stuff you're asking has been covered over and over and over again. Try a search, not just here but maybe bfc.com too....??


3.25 diffs are found in some E28's, specifically the ~82-84 533i, but IIRC it's also in some of the later 528e's- but not all.

And to answer another question someone posed about 3.64's being common in the early 318i's, yes- that's true, but those are small case diffs and we're dealing with medium case diffs here.

[rThor432]

What did the 3.25 come in?

I got two of them from dogleg trans equipped 323i's. But those dont grow on trees. Like Rigmaster said..

Which engine and tranny are you running though? If you're running an E36 transmission a 2.93 would be fine, but with a G260 or G240 with a .81 5th gear it's going to be very tall.

I'm running the S52 with the G260. I turn around ~2k rpm @ 65.