Limited Slip Diff Observation

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Lancsbob
Joined: Fri 15 Aug, 2014 17:35
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Location: Ormskirk

Limited Slip Diff Observation

Post by Lancsbob » Tue 05 Jul, 2016 08:30

Whilst looking for my transmission clunk i checked out my LSD & found
it no longer works (64k miles)& am wondering how many Z3s that are fitted with
LSDs are actually still working. They're all getting on now
so i reckon that 90% must have needed rebuilding, how many of us
would go to the trouble/expense of getting this job done. I'm not,
as my style of driving doesn't warrent the expense & am sure most
wouldn't notice if its working or not. So when your buying you Z3
with a LSD it probably doesn't work not that you'd know it.

Whats your thoughts?

Cheers Bob

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
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  Z3 roadster 3.0i
Location: Johannesburg

Re: Limited Slip Diff Observation

Post by Southernboy » Tue 05 Jul, 2016 11:11

How sure are you your's is an LSD diff ? There should be an"S" marked on the diff at the back which denotes LSD.
"Normal is overrated"
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siwilson
Joined: Fri 19 Jun, 2009 10:54
Posts: 782

  M roadster S54
Location: Horley

Re: Limited Slip Diff Observation

Post by siwilson » Tue 05 Jul, 2016 11:50

I thought all Z3s were limited slip with the non ///M have the TorSen and the ///M having clutch pack.

How do you know its broken? I recall a TorSen diff is difficult to test under no load situations. i.e raising the wheel and spinning one side will look like its broken when its not.
2001 M roadster S54 Laguna Seca Blue

kkkrisss
Joined: Thu 13 Jan, 2011 09:15
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  Z3 roadster 1.8
Location: Munich
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Re: Limited Slip Diff Observation

Post by kkkrisss » Tue 05 Jul, 2016 13:21

LSD is standard equipment for the M version only.

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motco
Joined: Tue 18 Aug, 2009 19:12
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  Z3 roadster 2.2i

Re: Limited Slip Diff Observation

Post by motco » Tue 05 Jul, 2016 16:03

My Sport 2.2i has a Torsen LSD 25%

Lancsbob
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Re: Limited Slip Diff Observation

Post by Lancsbob » Tue 05 Jul, 2016 17:42

I may be wrong but i was lead to believe that the 2.2 Sport had LSD as standard also
was told to check with one wheel off the ground. Where there 2 types of LSD fitted?
If this is incorrect would like to know how to check it. Does anyone bother doing so?
Glad to be put straight on these matters as i say it was only an observation.
I remember checking the spec of my car but have forgotten how to do this now but
seem to remember it saying it had LSD

Interesting reading your replies.

Cheers Bob

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Robert T
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Joined: Mon 12 Jun, 2006 11:35
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  Z3 roadster 1.9
Location: Cheshire

Re: Limited Slip Diff Observation

Post by Robert T » Tue 05 Jul, 2016 17:52

Spinning the wheel doesn't work on a Torsen (Torque Sensing) diff. You can test it by launching the car and seeing how many black lines you get - two = LSD, one = No LSD or broken LSD. :wink: You probably are better looking at the markings on the diff casing to see what you have.

LSDs were not fitted to that many non-///M models, and they are incompatible with the traction control on the 1.9. So a 2.8 with an LSD with have ASC, rather than ASC+T. The traction control works a bit like an electronic LSD and brakes the spinning wheel, giving more power to the one with the grip.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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peter2b
Joined: Sat 01 Nov, 2014 18:47
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  Z3 roadster 2.2i
Location: cheshire

Re: Limited Slip Diff Observation

Post by peter2b » Tue 05 Jul, 2016 19:28

I don't think my 2.2i has a LSD if I have to pull over to let some d*ck head pass if I floor it I get a red symble O with a /\ in it which I think is a warning that 1 wheel is spinning
peter2b

Lancsbob
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Re: Limited Slip Diff Observation

Post by Lancsbob » Tue 05 Jul, 2016 22:12

Just checked build spec & it turns out i have
option 209 LSD 25% but you say that there isn't a way to
check if its working.
Is it electronicly controlled?

Bob

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
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  Z3 roadster 3.0i
Location: Johannesburg

Re: Limited Slip Diff Observation

Post by Southernboy » Wed 06 Jul, 2016 12:08

http://websworld.org/marcel/ta23/diff.html

Click the link and read... :wink:
"Normal is overrated"
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Lancsbob
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Re: Limited Slip Diff Observation

Post by Lancsbob » Wed 06 Jul, 2016 13:02

Southernboy wrote:http://websworld.org/marcel/ta23/diff.html

Click the link and read... :wink:

Excellent.
You learn something every day....

Cheers Bob

alec.m
Joined: Tue 05 Oct, 2010 20:01
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  Z3 roadster 2.8
Location: Lymington

Re: Limited Slip Diff Observation

Post by alec.m » Wed 06 Jul, 2016 13:06

Brilliant article, thanks Barry :cheers

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c_w
Joined: Thu 19 Aug, 2004 17:50
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  M roadster S50

Re: Limited Slip Diff Observation

Post by c_w » Wed 06 Jul, 2016 16:13

2.2 Z3 sport has a 3.38 ratio Torsen LSD. I had one fitted to my coupe for a couple a years.

As above, they initially appear to be like an open diff (you turn one side and the otherside turns the opposite way). The good thing is, incident aside, they are maintenance-free.

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motco
Joined: Tue 18 Aug, 2009 19:12
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  Z3 roadster 2.2i

Re: Limited Slip Diff Observation

Post by motco » Thu 07 Jul, 2016 08:47

c_w wrote:2.2 Z3 sport has a 3.38 ratio Torsen LSD. I had one fitted to my coupe for a couple a years.

As above, they initially appear to be like an open diff (you turn one side and the otherside turns the opposite way). The good thing is, incident aside, they are maintenance-free.
I always advise the MoT testers that mine has an LSD, but is that really necessary with the Torsen type? It's only because of the brake test rollers IIRC

Edited to add: Having read that linked item and some further information, I shall continue with the practice of advising the MoT testers NOT to use the rollers. The Torsen diff is a very clever device; I am impressed.

Flight
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Re: Limited Slip Diff Observation

Post by Flight » Thu 07 Jul, 2016 09:56

I have followed this item with interest, I have always wondered what kind of differential is fitted to my June 2000 3.0i. Unfortunately I can not find any documentary evidence to prove which type it is. I shall take off the rear cover and investigate. The car has or is supposed to have DSC fitted, and a 25% LSD according to its original spec sheet, if so it can't be a torsen unit, as they don't slip. I will post the findings.
Flight

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motco
Joined: Tue 18 Aug, 2009 19:12
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  Z3 roadster 2.2i

Re: Limited Slip Diff Observation

Post by motco » Thu 07 Jul, 2016 13:57

Flight wrote:I have followed this item with interest, I have always wondered what kind of differential is fitted to my June 2000 3.0i. Unfortunately I can not find any documentary evidence to prove which type it is. I shall take off the rear cover and investigate. The car has or is supposed to have DSC fitted, and a 25% LSD according to its original spec sheet, if so it can't be a torsen unit, as they don't slip. I will post the findings.
Flight
Mine has a 25% unit and is a Torsen. This https://en.wikipedia.org/wiki/Torsen shows what 25% means. 3:1

Flight
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Re: Limited Slip Diff Observation

Post by Flight » Thu 07 Jul, 2016 18:51

Hi motco. Thank you for the information, most enlightening. I mistakenly assumed the 25% was angular displacement, and not a ratio.
Thanks again
Flight

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motco
Joined: Tue 18 Aug, 2009 19:12
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  Z3 roadster 2.2i

Re: Limited Slip Diff Observation

Post by motco » Fri 08 Jul, 2016 08:42

Flight wrote:Hi motco. Thank you for the information, most enlightening. I mistakenly assumed the 25% was angular displacement, and not a ratio.
Thanks again
Flight
You're welcome, Flight. I have to admit that it was all a bit vague to me too, until this thread popped up. I had the Torsen down as a soft option, but it sounds as if it is potentially quite useful. My Westfield has an open diff and on long fast power-on left hand corners on a track, the inside spins up unless I have a passenger on board. One day I'll swap it for an LSD... :colourful:

Blacknight
Joined: Fri 10 Apr, 2015 13:23
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Location: South Wales

Re: Limited Slip Diff Observation

Post by Blacknight » Wed 27 Jul, 2016 17:12

Out of interest, I'm still interested in getting a 2.0 Cosmos special edition at some point - does any body know if these had the Torsen LSD (or any other type of LSD)? I can't imaging that some did and some not being a special.

Dino D
Joined: Fri 10 Feb, 2012 16:59
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  Z3 roadster 2.8

Re: Limited Slip Diff Observation

Post by Dino D » Fri 29 Jul, 2016 12:56

c_w wrote:2.2 Z3 sport has a 3.38 ratio Torsen LSD. I had one fitted to my coupe for a couple a years.

As above, they initially appear to be like an open diff (you turn one side and the otherside turns the opposite way). The good thing is, incident aside, they are maintenance-free.
I'd love to hear how you got on with it. I'd like to try a shorter final in my 2.8 at some point and the 2.2 diff should be more readily available. Mine is not a Torsen though so might not be a straight swap. I've also read that the the Torsen is not as responsive as a clutch plated diff as per the older 2.8 and ///M models.

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