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View Full Version : E30 325E vs. 318i diff compatibility?


racer-x
03-28-2009, 07:59 PM
I have a 4.10 diff from a 318ti in my 1985 318i.

I want to change the ratio to a 3.23, and drop in a complete differential from an early 325E model.

Does anyone know whether the stub axles and drive shafts/splines are the same size, and if this is a straight drop in?

craz azn
03-28-2009, 08:04 PM
Early 325Es don't come with that gear ratio.

5thseries
03-28-2009, 08:13 PM
yah, after 89, things got sexy

racer-x
03-28-2009, 08:17 PM
325, 325e US-models 2.93, 3.23 medium standard - open
sports - mechanical limited-slip
325e before 9/85 2.79 medium standard - open
sports - mechanical limited-slip
325e 9/85 to 12/86 2.93 medium standard - open
sports - mechanical limited-slip|-
325e after 12/86 3.25, 3.46 medium standard - open
sports - mechanical limited-slip

craz azn
03-28-2009, 08:29 PM
So wheres that list from? Kind of cluttered and confusing.

North American market 325e's only came with 2.79 up until late '85, then later models are 2.93. Only in Europe were the shorter ratios available.

racer-x
03-28-2009, 08:48 PM
The list is from Wikipedia.
I seriously doubt that you can say that only those ratios were available. There was a 325es model, and the Super ETA engines that are almost never mentioned..... so I am sure those models had different ratios. (their redline was between a true E and an I powered car)

I need the question answered - DOES IT FIT? (are the cases different?)
If so then I can worry about gear ratio.

craz azn
03-28-2009, 08:55 PM
Wikipedia is crap. Its good for an idea, not hard facts. Believe me if you want or not, I don't care. Check in the ETK for yourself.

And yes, it will fit. All the medium case diffs are the same Type 188 diffs.

e30_kid89
03-28-2009, 09:41 PM
Listen to the Craz azn...

There is no 3.23 diffys for E30s, Not in North america at least...

richie_s999
03-28-2009, 09:56 PM
Listen to the Craz azn...

There is no 3.23 diffys for E30s, Not in North america at least...

I agree listen to him, He know's his shit!!!!!!!!!

Axxe
03-29-2009, 12:44 AM
It will all fit. Even E28 diffs fit (E24 as well IIRC) if you use e30 stub axles and rear cover.

Mystikal
03-29-2009, 02:38 PM
Also adding to the misinformation, there was no 4.10 in a 318Ti. Just 3.45 (manual) and 4.44 (auto).

racer-x
03-29-2009, 05:14 PM
I stand corrected - mine is a 4.44 actually. I guess it's been a while since I bothered to actually give it any thought.

I just found a 3.23LSD, so for whatever reason, this ratio exists.

racer-x
03-29-2009, 05:19 PM
I need a 2.93 LSD as well.
PM with details