In need of a new diff and a little advice

[gouba 0]

Hi all

i recently picked up a 320 which has been reshelled as a 325. It had a few small issues which are being worked through but one of the problems is the diff was a bit long.

I got under and found out that the previous owner had put a 4.45 small case diff in there (i can figure out the logical reason why) which is from a 318 automatic.

Anyways, I need to find something a bit shorter so I can actually used 1st and second gear for more than ten seconds.

Does anyone have a recommendation for a ratio I should be using? I use the car mainly for day to day driving but I would still like to have a reasonable level of acceleration.

great forum btw, the level of information on this site is awesome.

Thanks in advance,

Matt

[pureboiracer 0]

youve confused yourself a little there mate, longer is what your after. the diff you have currently got is a short ratio, because its all accel and no top end, a long ratio is lots of top end.

from reading your post i am unsure on weather you put your 2l motor into a 2.5 shell or other way around... if its a 2.0l i would say run something near a 3.9 or a 4.1 if its the 2.5 motor you want something near a 3.64

[gouba 0]

Ah I typed this too early in the morning and mixed up my words.

It is a 320 body with a 325 running gear transplanted in (obviously bar the rear diff)

So around a 3.64 is what I need, do they come in a small case or are they in a medium case (conscious of the fact ill have to change my driveshaft over as well)

[pureboiracer 0]

um small and meduim i believe. probably one of the most common ratios so not too expensive either.

you shouldnt need to change your driveshaft or axles to change from small to medium.

[gouba 0]

My understanding with the medium case is that it was the same width as the smallallowing the axles to remain, but it was a tad longer requiring the change in driveshaft.

*goes off and googles a little more*

[pureboiracer 0]

no, same driveshaft, there is a slip joint near the center of driveshaft that will take up any difference.

[gouba 0]

no, same driveshaft, there is a slip joint near the center of driveshaft that will take up any difference.

Awesome, one less thing to buy.

Thanks for your help

[BM WORLD 1286]

normally a e30 325i would use a medium case diff with a 3.64 or 3.73 etc.

i have most diff ratio's .

small and medium

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