E85 Z4 and E46 differentials interchangeable?

O

oalloyd1

Member
Hi all,

Would like to put a shorter rear diff in my 2003 Z4 3.0 - Do you know if a used E46 diff from something like a 316i / 318i would just bolt straight on? Anything I should consider when doing this?

Cheers,

o
 
here's a list of ratios for the Z4- http://www.bokchoys.com/differential/GearRatios_E46.htm
It's US list so can anyone chime in if it's any different for UK specs

3.64 from the auto 2.5/3.0 would be the best compromise, bear in mind the lower you go the shorter your first gear, so you may find your starting in second to avoid the first change.
 
If your looking at diffs etc from something like a 318 it might be worth comparing one with the ratios in a 2.0 E85. At least you know the E85 one will bolt in place. Not sure about the propshaft compatibility though.
 
I believe anything from an e46 will bolt in they all have the same rear subframe. And I would imagine the same dif casing. M cars have a completely different rear set up. Saying that if you buy the whole rear subframe thst dose bolt straight in.
 
Cheers guys - I'm keeping an eye out for a used LSD as really cant justify dropping £1200 + fitting into 1 mod as the car wasn't hugely expensive in the first place!

Cheers,

o :)
 
M factory ones are cheaper. And i have one i cant rate it highly enough. I am a mechanical enginneer and the quality of this diff is second to none.

You just won’t find a cheap LSD M ones don’t fit unless you change the whole rear axle. And by the time you have brought the bits it will cost the same for a second hand parts. There is no point if you ask me. And no other bmw apart from M cars of this age have LSDs.

If you want one you will just have to take the cost on the chin buddy.
 
Machine monkey said:
I believe anything from an e46 will bolt in they all have the same rear subframe. And I would imagine the same dif casing.
Click to expand...

No, there are also e46's with 168 diffs. And the z4 2.0 also has a 168 diff.
The TS needs a 188 diff


He may also have to swap over driveshaftflanges and propshaftflange. Especially swapping the propshaftflange is specialists work because you have to set the preload (there's a crimping sleeve inside between the two pinionbearings)
(although you can do it yourself of course with the right tools and data, but I wouldnt let an average mechanic do this)

And of course swap the end plate; the z4 has cooling fins on it.
 
If you are serious about having a track car then, IMHO, your first mods should be suspension related. An LSD literally transforms the car, if you don't want to spend that sort of money then you're not really making a track car you're just driving a stock/stripped/fiddled car on a track.

For the rear axle I would suggest getting a subframe and refurbing it (strip/protect/paint) along with poly bushing it all, then just swap them over.
 
Sorry to ask but as a newbie and going over all old posts looking for help ..
I’ve found a e46 m4 at salvage yard with a complete rear subframe , hubs and bake assembly would it fit to my E85 Z4 ? Bigger brakes and the LSD being my main targets
 
Hi I have a 2004 E85 that I would like to convert to m3 LSD & rear brakes . However I have been told it’s such a pain in arse to just swap the brakes because of handbrake issues , lathe work required to machine the hat to suit.
I have been offered a complete rear subframe from a E46 M3 so would it be possible to just remove and swap my existing rear axle setup for the M3 ?? Does the drive shaft work together ? Would I need a new one , and does the handbrake cable need swapping out ? Many thanks in advance
Also on look out for a 6spped box if anyone had one knocking about on readiness for S62 engine upgrade
 
You must log in or register to reply here.
Back
Top Bottom