S54 advice and considerations

[Wanganstyle]

good to know. for me the appeal of the MZ3 was low cost (if you can find one), direct fitment, and comes in the ratio I desire. I dunno about using a clutch type diff in my car.. and I don't really want to use a 250,000 mile VC diff as a base either.

Clutch rear LSD is THE preferred high performance rear LSD for awd vehicles; reference evolution's and STI's - both avail in rear bias and 50/50 settings, clutch is always spec'ed for the highest performance models.

Awd with rear bias with Torsen is nice untill you come across an uphill hair pin with large elevation gap. OR a turn like #5 or #6 @ Laguna with tricky berms

Then you will curse that you are not running a clutch pack style LSD.

[nando]

Agree. I had a mz3 torsion in my s54 powered car. worthless half the time. one wheel wonder exiting over bumpers. Skip that. Give me an e30 locker.

j

good to know. for me the appeal of the MZ3 was low cost (if you can find one), direct fitment, and comes in the ratio I desire. I dunno about using a clutch type diff in my car.. and I don't really want to use a 250,000 mile VC diff as a base either.

[Jason89i]

WHAT do you feel is "better" about the Z3m diff unit besides the trendy cover?


[B]better? I Disagree; ....................

Z3m diff is very tame setup from factory ON PURPOSE.

Agree. I had a mz3 torsion in my s54 powered car. worthless half the time. one wheel wonder exiting over bumpers. Skip that. Give me an e30 locker.

j

[gobuffs]

I doubt I'll ever get rid of my 4.10. :-) Although if I get faster I might need a 3.91 instead.

[Wanganstyle]

Wangan, the Z3 Mcoupe LSD unit is definitely different/better than the e30/e24/e28 units.

WHAT do you feel is "better" about the Z3m diff unit besides the trendy cover?


better? I Disagree;


I don't think one can objectively make blanket statements just because an item costs more or is from an obscure model. Espically if the "why its better" is unknown.

IMO even the most interesting/special Z3m LSD unit is slightly DE-TUNED in comparison to any plane jane E30 LSD; its LESS Aggressive in many ways

teardown /internal Photos of all styles of LSD were posted on this forum quite some time ago...........

It (z3m and z3 in general) is different somewhat and sometimes; internal specification varies. BMW used Z3 chassis as a very weird test bed; usa production - not a german built thing. Very strange test in many chassis dynamics, power train combos. Small enough build to make weird bastard children configs!

the guts in any Z3m LSD (torsen or clutch type) have not much locking when airborn.
IF it happens to it will have be fitted with a standard 188mm e36 LSD unit, and those are not any better than any e30 unit.

the Z3 clutch units are in both standard e36 style and funky experimental style.

Funky units are actually configured in an archaic Alpha Romero (circa 1970's) style, have no/very little locking when one wheel is airborne - come drive a big boy track like Infineon or Laguna and you will see this show its ugly head. If you find my thread with photos of the guts, internal stacking config then perhaps you would understand. IF you actually go through the internals of a decent amount of them you will find some strange variations as well to the funky config.

What are these specifics? Find out by building it.

Perhaps its my rally background showing, but LSD is a custom affair. LSD NEEDS TUNING


Built Not Bought.

The aptitude and performance level of tuning of many non-track performance based tuners shows HUGE when otherwise decently equipped cars just run random secondhand rear diff/ with stock configuration and expect it to "be good".

this is the R3V way of doing things. :weak::weak::weak::weak:

Many R3V'ers just wish to have a giant monster mod list and 24v swap to show off- Where is the high performance Chassis innovation, Driveline innovation and efficiency to create better more innovating E30's???

Just something I have noticed. many spend 2-3-4-8k easy on some marginal 20% hp increase, hours and hours rebuilding sub part 24v engines. BUT nobody really cares to tune or understand diffs- and this is the FINAL DRIVE to the GROUND. Only more determining factor of driveline tuning than diff is TIRES. One building an e30 could easily call Jim Blaton, Performance gearing, Dan @ DOL, and just order a unit built if desiring a higher level of tuning.

Most of the higher performance Japanese cars getting actually tuned are not even bothering with stock LSD because the owners are not broke/cheapasses. Even cheap garbage 240SX / drift/grip/track cars are fitting nice LSD units.

The m coupe LSD u speak of in either clutch config or torsen would put down SLOWER lap times on the mountain or track if installed in the typical modified E30 - YOURS with S54 would be included...

try it, tell me about it.

Seemingly people are afraid of really modifying how the car handles; LSD is the only analog chassis dynamics weapon a 2WD chassis platform can easily tune and customize.


Z3's including m's actually had 3+ different diff internals from the factory. In many ways the common e30 LSD is an upgrade item. I am talking clutch LSD center unit vs clutch; Torsen is a different beast.

A gear type diff handles completely different than any clutch style. Torsen in an e30 is great handling (in my experience- I fit one 2 months earlier in year in my e30;

Torsen was my baseline for handling as it is most similar to an open: Least hampering of true traction line, only 100% consistent torque transfer diff you can choose; transitions cleaner than with a clutch LSD (IMO)

1. Open diff
2. Torsen-2 way clutch
3. 1.5 way clutch now.

The chassis is fastest with a high locking 1.5 tight or 2.0 way clutch unit (IMO). "fastest" to the nut behind the wheel. There is a reason that track weapons and OEM BMW motorsports spec Clutch LSD units - NOT the street units; Aftermarket BMW Motorsports unit.

the Z3m funky unit can be built up for high performance yes, but that requires a full build / recofig and fresh EVERYTHING - same effort/labor for a high output e30 OEM LSD result and I still feel a re-configured E30 325 whatever LSD cartridge would be better end product than a fully re-configured z3m funky unit.

Z3m diff is very tame setup from factory ON PURPOSE.

[Jason89i]

I've had the 3.15, 3.23, 3.46 and 3.64 behind my s54/zf5. my preference: 3.46 for the street, 3.64 for the track. J

[gobuffs]

Wangan, the Z3 Mcoupe LSD unit is definitely different/better than the e30/e24/e28 units.

That was my understanding too, but an M coupe owner that is much more knowledgeable than me says it is hit or miss and mostly miss with the torsen. It was heavily advertised when the M coupe came out but it appears that they really have a clutch pack diff.

[e30polak]

Wangan, the Z3 Mcoupe LSD unit is definitely different/better than the e30/e24/e28 units.

[Wanganstyle]

I was led to believe the 3.23s were torsen

Who knows. Some z3 supposed to have torsens end up equipped from the factory as clutch units. Best to actually look inside the diff

With an awd car + trackwork a clutch LSD rear set high locking @ 1.5 or 2.0 way would be the ticket for lift throttle/ turn in / smack throttle corner entry/exits.

[Wanganstyle]

I've used the fuck out of LSD in plenty of non-M cars !!!

There's also plenty of M cars driven by people who buy them for the status !!!!!!

Yes. Non m car LSD is great.

What status.

If m5 v10 m car ok, there is about no feasible status, or manliness factor about a z3m. Just an ugly effective trailing wind break.

Z3m Is not a chick picker upper like a 911 or Ferrari or big AMG. Even if you used the dog net to carry some only a few Ltw editions could fit in the hatch.

[nando]

Z3m LSD is just a stock 188mm LSD. when putting down lap times with it compared to any random e30 LSD in 100% function there is Nothing really special performance wise in competition.


actual milage means not that much in the wear scheme of these things, usually the RPMS it has seen, heat stress kills the clutches.

I'm sure any of us seriously having fun with a s54 M coupe could easily melt/burn/smear the clutches in 11,000 miles.

random LSD units from the 80's and 90's in low rpm automatic cars are usually in better shape internally (dogs, ramps, housing, clutches) wear than M-units with less than 1/2 the milage. highest wear load on a Medium case is E36m (s50b30 euro, s52/50 us, and most stressful is Z3m with S54!!!)

M cars USE the LSD, so do the drivers !!!

I was led to believe the 3.23s were torsen

[accident]

M cars USE the LSD, so do the drivers !!!

I've used the fuck out of LSD in plenty of non-M cars !!!

There's also plenty of M cars driven by people who buy them for the status !!!!!!

[Wanganstyle]

I've got a Z3m cover already. half of the appeal of the Z3m diff to me is the LSD.. :(

Z3m LSD is just a stock 188mm LSD. when putting down lap times with it compared to any random e30 LSD in 100% function there is Nothing really special performance wise in competition.


actual milage means not that much in the wear scheme of these things, usually the RPMS it has seen, heat stress kills the clutches.

I'm sure any of us seriously having fun with a s54 M coupe could easily melt/burn/smear the clutches in 11,000 miles.

random LSD units from the 80's and 90's in low rpm automatic cars are usually in better shape internally (dogs, ramps, housing, clutches) wear than M-units with less than 1/2 the milage. highest wear load on a Medium case is E36m (s50b30 euro, s52/50 us, and most stressful is Z3m with S54!!!)

M cars USE the LSD, so do the drivers !!!

[e30polak]

I've got a Z3m cover already. half of the appeal of the Z3m diff to me is the LSD.. :(

Same here, especally with such little mileage on it. I just don't care for the ratio for my s54 + ZF trans set-up. :p

[nando]

I've got a Z3m cover already. half of the appeal of the Z3m diff to me is the LSD.. :(