Will 2002 M-coupe diff fit compact?
 

^^^

i'm pretty sure but not positive...i know, it helps a lot

larger size diffs will fit (eg: e30 LSD), but you may have to "mod" the bottom of the ti a bit to get it in there. that said, the bolt holes are the same.

then there's the issue of whether or not the ti halfshafts will fit. are you keeping or swapping those? the ones for the ti are longer than say e30 halfshafts, but there's a running argument over whether or not it matters.

are you doing an engine swap, boosting the stock 4 or what? keep in mind the m-coupe diff has a ratio of like 3.23 vs 3.45 for stock ti diff. what does this mean? it means you'll have slower acceleration but higher top end potential (if it weren't limited) and lower revs at the same speed.

You'll need to get an e30 diff cover (since the M Coupe uses two mounts on the cover, and our cars mount with one) and two e30 output shafts (half shafts), but other than that, it's plug n play.

Cali-ti brings up a great point. If you haven't tweaked the motor, you'll be making the car slower 0-60, but you'll likely raise MPGs, and have better traction. I have a 3.25:1 LSD with my S52 powered 318ti. It's perfect for that car.

actually, the m-coupe finned diff cover is a very desired cover for ti swappers. i have one on my e30 LSD now (see my gallery for pics). it makes things even tighter, but absolutely does fit (and the m-coupe diff cover mount is stiffer rubber as well). keep in mind, this is the m-coupe diff and NOT the m3 coupe that we're talking about (or it's what i'm talking about anyway, lol).

i'll actually be swapping in a complete m-coupe rear subframe, trailing arms, half shafts, diff and brakes in the future. hopefully around the same time i do an engine swap :)

thanks for your replies guys!
so, i did an m52 2.5L swap and i guess i have to replace my 3.45 open diff since the gears are too short and revs too high. i also heard that it will eventually fail.
the diff i might get: 02 m-coupe 3.15 LSD with 55k, price—$230.
is it worth getting it?
thanks again!

are you sure it's a 3.15? i thought the m-coupes were 3.23. i should check the one i have sitting in my garage, but it's boxed up and possibly under a bunch of stuff.

it *might* be too big a change in ratio. keep in mind the m-coupe had a good deal more power to push a lower ratio diff. i guess it really depends on what you're after.

3.15 was used form 2001-2002 with the s54 engine
3.23 was used up to 2000 with s52 engine

both M coupe and M roadster use a 1 mount only. The two mount option was and after market option to reinforce the subframe using Randy Forbes kit.

wow, didn't even know about that mod for the mz3/m-coupe: http://www.rfdm.com/Randy/BMW/pics/p...Reinforcement/

cali-ti,

what mod to the rear are you talking about? i just installed an E30 3.73 LSD this past weekend and i you are spot on... the diff barely fit. i did not have to cut or bend the body in any way, shape, or form. will i need to do this with the MCoupe cover? i plan on getting this cover in a few months. other than removing the diff entirely, i dont see how i will be able to install the cover with such a limited (understatement) amount of space.

see the lovely pics in my gallery :) if it fit w/o mods with the regular diff cover, i think you'll be alright. the bolts on mine would not clear. it seems to fit on some and not on others, which i don't fully understand.

EDIT: btw, it's even more fun when you have the da'lan hitch!

hehe now that i have done this swap (not m3) i understand this thread a lot more

3.15 is the stock M3 rear ratio. Since the transmission ratios are the same between the ZF and Getrag, how could this be bad? You're basically replicating the performance of a stock M3.

but he has a 4-cylinder :)

EDIT: nm, i'm confusing threads ... /sigh

EDIT2: he has m52 which isn't as much power, but i would guess it would still be fine (considering sk8 just used a 2.79 in his 4-cylinder and says it's not that bad). i'll just shut up now :)

i dont think he does have a 4 cyl

his user name is

98Silver323TI

so i bet he has an m52

is the m3 diff you are putting in a limited slip?

EDIT:ya i bet having that extra 2 cyl would make the 3.15 get up and go just fine