Zf tranny...what diff?

[Gooch]

Enough with the fighting. Diffsonline has an excel chart for the ZF gearing and you can plug in your desired ratio and tire size.

http://www.diffsonline.com/techinfo/GearingCalculator.xls

I was originally thinking going with a 3.25 for my S52/ZF. Then I was reading some threads and realized I didn't want such high revs on the highway, so I thought a 2.93 would be good. Then I realized you could get a 3.15 out of a Z3 and figured it'd be the perfect compromise. Long story short, I found a 2.93 out of an Eta in a junkyard so I'm going to go with that (at least for now).

[kalib0y]

Enough with the fighting. Diffsonline has an excel chart for the ZF gearing and you can plug in your desired ratio and tire size.

http://www.diffsonline.com/techinfo/GearingCalculator.xls

I was originally thinking going with a 3.25 for my S52/ZF. Then I was reading some threads and realized I didn't want such high revs on the highway, so I thought a 2.93 would be good. Then I realized you could get a 3.15 out of a Z3 and figured it'd be the perfect compromise. Long story short, I found a 2.93 out of an Eta in a junkyard so I'm going to go with that (at least for now).

High revs is same reason why I kept my 2.93. I figure if I end up going with forced induction then I would love the longer gears but for now the 3.25 is fine. I dont have a loud droning exhaust so my 80mph is tolerable.

[e30rapidic]

according to that spreadsheet a G260 with a 4.10 in 5th is almost identical in rpm's to a zf trans with a 3.25 at 80. awesome, since I've ran the 4.10 for a long time.

[butters]

So to prolong this thread even further, I have to clarify something for myself as I've been searching and reading for awhile now but haven't really come across a straight answer...

I have a '95 S50 w/ZF310 and original '95 M3 driveshaft all out of the same car, have not picked up a diff yet. Should I put this driveshaft up for sale and look for a later model shaft as well as an eta 2.93 (this is the ratio I want) or is there some way I can utilize the part I have? I am looking to do the least fabrication possible. Will the late driveshaft+eta 2.93 bolt right up?

[ck_taft325is]

If you go with a late (328i 96+) you should be good to roll.

[e30rapidic]

So to prolong this thread even further, I have to clarify something for myself as I've been searching and reading for awhile now but haven't really come across a straight answer...

I have a '95 S50 w/ZF310 and original '95 M3 driveshaft all out of the same car, have not picked up a diff yet. Should I put this driveshaft up for sale and look for a later model shaft as well as an eta 2.93 (this is the ratio I want) or is there some way I can utilize the part I have? I am looking to do the least fabrication possible. Will the late driveshaft+eta 2.93 bolt right up?

I am running an S50 with the zf trans, using the front half of the e36 driveshaft mated up the back half of my regular M20 driveshaft and diff. So you will be able to use what you have.

S50, zf trans, e36 front half of driveshaft, e30 CSB, e30 rear half of driveshaft

[shiboujin]

+1 with e30rapidic. Although you should get it balanced at that point.

[butters]

+1 with e30rapidic. Although you should get it balanced at that point.

I'd have to look into where I can get that done. Is it worthwhile, or should I just go with 100% eta driveshaft&diff... or does that not work with the Zf hence the need to hybridize it

[shiboujin]

I've never seen anyone use an eta drive shaft. The lengths make sense to me. You can look them up on realoem.com. The ZF is a large guibo so the eta drive shaft should fit that.

Although, balancing a drive shaft makes it so you know it's good. I'd have the U joint checked/replaced if necessary too. Then you won't ever chew through guibos and CSBs.

[butters]

I have a 318, I'll have to check if the rear half of the M42 driveshaft would work. Found an eta diff on ebay for 290 shipped, not sure if that's a good deal and the driveshaft connection looks a bit rusty..

Long story short, I found a 2.93 out of an Eta in a junkyard so I'm going to go with that (at least for now).

I'm not planning on doing the swap until mid-May. If there's a chance you'll be swapping out of the 2.93 any time soon shoot me a message.

[Mr.SWISS]

Look at E28's for 3.25 diffs. That's where I got mine from (only using it for driving to the Picnic).

Your leaving the warm south for the cold north? That's a helluva drive homie.
:eeek:

[FredK]

You're damn fucking right you're happy I came into this thread and put a gleam of awesomeness in an otherwise useless thread.

Must have been an accident.

[nrubenstein]

So to prolong this thread even further, I have to clarify something for myself as I've been searching and reading for awhile now but haven't really come across a straight answer...

I have a '95 S50 w/ZF310 and original '95 M3 driveshaft all out of the same car, have not picked up a diff yet. Should I put this driveshaft up for sale and look for a later model shaft as well as an eta 2.93 (this is the ratio I want) or is there some way I can utilize the part I have? I am looking to do the least fabrication possible. Will the late driveshaft+eta 2.93 bolt right up?

Or you can swap the input flange on the diff and use your existing driveshaft. Or just use a Z3 diff (from a 2.8 or 3.0 or 3.2 - I believe the little engines still used the 4-bolt flange).

[328ijunkie]

Yes they are since I am running 235/40/17. I may be wrong ,but my thinking is that is the overall rotation is larger then the RPMS should be lower right?...Well actually I know I am probably wrong but I would love a technical explanation if possible...

Was your car a 4cyl? original cluster? Have you checked the speed sensor?
And tire size does change actual road speed but wont change the cluster reading.

[kalib0y]

Was your car a 4cyl? original cluster? Have you checked the speed sensor?
And tire size does change actual road speed but wont change the cluster reading.

Actually the cluster is from the E30 M3. Could that be the culprit? I havent checked the speed sensor yet.