323i diff

[dazleeds]

can i put a c reg 323i diff on my f reg 320i se??

mine whine likes hell also would theyre be any benefit by fitting the 323 unit???

cheers Daz leeds

[Davenotouring]

Dunno what ratio the 323 one will be, check the ratio on the tag. Could even be a slipper.

If they are both large case, it should bolt straight up.

[dazleeds]

how can i tell if its large or small case?? sorry but i got no knowledge when it comes to diffs and ratios will go look at tag now if i can see it back in five Daz

[320Touring]

if yours is a 320 on an f then theres a good chance that its a small case diff....prob a 4.10

if so you need to shorten the prop to get it to fit the 323 diff which is large case iirc

[dazleeds]

damn cant see it prop ill have to jack it up in the morning and have a good look cnt be rs,d now lol
so what should i be looking for on the diff?? cheers DAZ leeds

[E30BeemerLad]

I may be wrong here, but I am sure I was once told that LSD diffs have either a S or a Z stamped on the casing somewhere? Anyone else come across this? Sure I read it in Practical Performance Car mag, they had an E30 buying guide at the back.

[320Touring]

the LSD's have an S stamped into the casing and also infront of the diff number

S371..... = 3.71 LSD

HTH

[Davenotouring]

There would be an S in front of the ratio, something like...

S 3 91 xxx

That would mean it was an LSD ratio 3.91

The small case has a different amount of bolts on the cover methinks, but not sure. Someone else will know I hope!

[dazleeds]

cheers lads
will pop out in a bit and jack up just in case it is a slipper then ill swap it tommorow

still need to know how i can tell small from long case diff if anyone knows cheers Daz leeds

ps whats best ratio to have??

[Davenotouring]

3.91 is good.

3.73 is v. rare and a good compromise.

3.64 is good for motorway cruising, maybe very slightly low for acceleration especially on a 320. I can't see a problem with any.

Some were even 4.10, 3.25 (M3).

[dazleeds]

anyone???

as above cheers Daz

[astondg]

I thought somebody said that the larger diff has more bolts than the smaller one. That could be wrong though and even if it is right I don't know how many botls on each, might be 6 and 4 or something.

The owners handbook for my 323i says the diff was a 3.45 or 3.25 ratio (some markets) and there was an optional LSD, but doesn't say what ratio for the LSD. Mine was the LSD, I have had the internals changed for a 4.1 LSD now but I think the case is still the same. I can't see what ratio is stamped on it though and I don't have a jack handy. Either way if you had a 4.1 the 323i diff might be too low a number (geared for highway use and high speeds).

Aston