Tranmission/Driveshaft/Differential Combinations?

[94is]

Hey guys. I have a Getrag 250 (e36) transmission that I am using with an OBD1 M52. I am finding conflicting reports on which driveshafts and which differentials I can/should use with this swap. I am also doing a transmission swap to this same car (oh joy). Any input is greatly appreciated. :)

[FredK]

A 3.25 will keep the highway revs low-ish, but the car will have great response in every gear. Notch up to a 3.46 to get a slightly better gear advantage.

A E36 325i manual driveshaft would fit the best. 12 mm input flange holes match with the 12 mm output flange holes of the trans.

[Shoomakan]

Lol I put a 3.73 on my M30... All shits and giggles. :D

[94is]

A 3.25 will keep the highway revs low-ish, but the car will have great response in every gear. Notch up to a 3.46 to get a slightly better gear advantage.

A E36 325i manual driveshaft would fit the best. 12 mm input flange holes match with the 12 mm output flange holes of the trans.

So iirc, all e30's use the small case differentials, correct? So the 3.25 and 3.46 will have to be out of an e30.

The car I'm building will be mainly used for DE's and autoxes, so we're not too concerned with fuel economy and reasonably high revs on the highway. My e36 has a 3.38lsd and is at 4,000rpm at 80mph in 5th. I think something similar to that would be perfect for the e30.

The reason I am using the Getrag 250 is because I got a great deal on it. :-P

Okay, so anyways. With the M52 and Getrag 250, should I get a Sachs clutch kit for a 325 or 328? I was given a new flexdisc from a 95 m3, which won't work with the 325 driveshaft (according to realoem). :(

Lastly, which flanges should I get to mate the differential to the halfshafts on the '87 325is? Are all e30's the same? I know e36 325 and m3 are completely different, so this is why I ask.

[FredK]

So iirc, all e30's use the small case differentials, correct? So the 3.25 and 3.46 will have to be out of an e30.

Four cylinder E30s use small case diffs. Six cylinder E30s use medium case diffs. Although the E36 has a medium case diff, the housing is different. Only E30 and Z3 diff housings will work.

The 3.25 and 3.46 are most commonly found on the E28 535is or some 528e. You will have to swap to the E30 diff cover and output flanges.

Okay, so anyways. With the M52 and Getrag 250, should I get a Sachs clutch kit for a 325 or 328? I was given a new flexdisc from a 95 m3, which won't work with the 325 driveshaft (according to realoem). :(

Yeah, with a Getrag 250, you can't use the 95 M3 guibo--the bolt pattern diameter is too big. Whatever flywheel you plan on using, get the clutch kit for that. 328 flywheel, 328 clutch kit. 325 flywheel, 325 clutch kit. Many people upgrade to an S50/52 flywheel/clutch kit.

Lastly, which flanges should I get to mate the differential to the halfshafts on the '87 325is? Are all e30's the same? I know e36 325 and m3 are completely different, so this is why I ask.

Yes, the flanges on all medium case diffs are the same. The flanges from a small case diff (like from a 318is) won't work.

[matt]

Lol I put a 3.73 on my M30... All shits and giggles. :D

lol not with an e36 transmission you didnt.

Kim... learn to search. Fred is only being nice to you because you're a girl, we've been over all this shite a billion times.

[matt]

Yes, the flanges on all medium case diffs are the same. The flanges from a small case diff (like from a 318is) won't work.

Hmm... glad I proofread this. A rare mistake for you, Fred.

Not all medium case output flanges are the same. The e28 differentials use larger output flanges, but they swap right over. So, you can take a 3.25 diff out of an e28 (only car they came in) and swap it into an e30 if you change the rear cover and change the output flanges.

[FredK]

Kim... learn to search. Fred is only being nice to you because you're a girl, we've been over all this shite a billion times.

:finger:

As long as "what engine mounts" or "what booster" isn't asked, I'm ok. Maybe.

Hmm... glad I proofread this. A rare mistake for you, Fred.

VAT!!!!????? :mrgreen:

Well, what I was saying was that all E30 medium case flanges are the same... :giggle:

[matt]

So umm, I heard you have to change the oil pan? Why? I am going to do it without changing it.

[94is]

Yeah, with a Getrag 250, you can't use the 95 M3 guibo--the bolt pattern diameter is too big. Whatever flywheel you plan on using, get the clutch kit for that. 328 flywheel, 328 clutch kit. 325 flywheel, 325 clutch kit. Many people upgrade to an S50/52 flywheel/clutch kit.

I really want to throw a ltw flywheel in there. I have the 10.5lb JB racing fly in my e36 and I absolutely love it. :D

lol not with an e36 transmission you didnt.

Kim... learn to search. Fred is only being nice to you because you're a girl, we've been over all this shite a billion times.

I just kept finding conflicting evidence. :dunno: Over on bfc I get pm's constantly about motor swaps, tranny swaps, sunroof repairs, etc etc. Oh and I recently discovered that the master cylinder setup on the E30 is completely different from the E36. I'm stoked that it isn't like the e36. That one is such a pita.

:finger:

As long as "what engine mounts" or "what booster" isn't asked, I'm ok. Maybe.

I already know what to do about those.

Btw, is the e34 m5 master cylinder really $150?!

[94is]

So umm, I heard you have to change the oil pan? Why? I am going to do it without changing it.

I was planning on just hammering it out of the way. Isn't that what all of you guys do?

[matt]

Usually I a notch in the subframe.

The M5 master cylinder isnt the only option, there are a ton of them that will work. But you'll have to wander around a junkyard or parts place with a couple wrenches and a booster to figure it out. $150 is not so bad by comparison....

[94is]

Usually I a notch in the subframe.

The M5 master cylinder isnt the only option, there are a ton of them that will work. But you'll have to wander around a junkyard or parts place with a couple wrenches and a booster to figure it out. $150 is not so bad by comparison....

I was just surprised because it is more than twice as much as the other ones.