M3 LSD breakaway torque

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   Hi All,
Does anyone know the correct value for the diff breakaway torque?
I've got two M3 3.25 diffs on the bench and one has 51 lb/ft (allegedly a good 2nd hand item with around 65000miles on it)
Mine has 41 lb/ft breakway torque. (111000 miles)

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SteveM Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 23-February-2004 Location: Scotland Status: Offline Points: 238	Topic: M3 LSD breakaway torque Posted: 07-April-2004 at 13:25
	Hi All, Does anyone know the correct value for the diff breakaway torque? I've got two M3 3.25 diffs on the bench and one has 51 lb/ft (allegedly a good 2nd hand item with around 65000miles on it) Mine has 41 lb/ft breakway torque. (111000 miles)
	Steve Scottish Cecotto

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M BLUR Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Really Senior Member II ZeeMax ROADSTER Joined: 04-August-2003 Location: United Kingdom Status: Offline Points: 1557	Posted: 07-April-2004 at 13:28
	No idea Steve, But if you want to relieve yourself of one of them diffs then I'll oblige you as I've been thinking about raising the final ratio..
	www.lbmracing.com 1998 Zeemax M Roadster 2005 X5 3.0D Sport 1991 Esprit SE Race car

SteveM Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 23-February-2004 Location: Scotland Status: Offline Points: 238	Posted: 07-April-2004 at 13:35
	The 3.25 is the standard ratio for a Euro E30 M3 (I think the Sport Evo has a 3.15, and the US M3 has 4.15)
	Steve Scottish Cecotto

Mags Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member I Joined: 31-March-2004 Location: United Kingdom Status: Offline Points: 287	Posted: 08-April-2004 at 10:08
	Steve, Just seen I'm cross posting with you on S14.net Isn't the torque in the M3 manual I sent you (it was you wasn't it?) I've seen it somewhere, will dig it out. I know what you mean on the cost of one, I paid the same. I was hoping it was going to be a very simple swap job, sounds not so simple!! Mags Edited to add: I just looked through TIS and the M3 manual and it has no torque setting for the M3 diff, but it does for the same type of diff (type M?) for an E36. heres what it says: http://www.s14.net/photopost/data/500/838diff.JPG Edited by Mags

SteveM Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 23-February-2004 Location: Scotland Status: Offline Points: 238	Posted: 08-April-2004 at 11:22
	Mags, It was me you sent the manual to, but unfortunatley it doesn't seem to list figures anywhere. I've just posted on s14.net the info I got from ZF this morning. The E36 numbers look similar. I've tried different shims so far and got up to 56 lb/ft, but have to check I'm not completely squashing the spring washers. Swapping the diff was a pain (on the driveway outside in the rain) but If i take away all the messing around, it's probably a 3 hour job to remove one and refit the other. I've now got to try and find a way of testing it on the road to see how things change/improve with the increased lock-up.
	Steve Scottish Cecotto

Mags Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member I Joined: 31-March-2004 Location: United Kingdom Status: Offline Points: 287	Posted: 08-April-2004 at 11:36
	Steve, Regarding the question on the plates, I think these are the NLA parts. When I was working on the price to get mine re-built I got a number from Nigel Mosley of a guy who does their re-builds, I think he was up north (for what its worth) and said that you can machine the casing to accept a bigger/stronger LSD which is still in prod. I don't know where his number went as he wanted about �500(!) for the whole rebuild including parts and like you I sourced a used diff (although I since found out my LSD is good, its just the noise I am getting which is hopefully just a bearing) Might be worth getting his number and have a chat? On the subject of splitting an LSD for parts, I was hoping to swap mine (still not done this due to work/rain/hangovers) and then see if the bearing needs replacement and sell it on to recover some of the cost of the other diff. The problem I have is to see if the bearings are good when replaced is to re-fit it and see if the noise has gone away, then I (hopefuly) have a used diff to sell on. I dunno how much the bearings would cost so I may or may not have a good LSD but knackered diff I might be able to sell. Confused? I am! See what answers you get, no doubt new plates would be better than another used diff! Also, I nearly forgot, but the guy's on S14 recommend some Redline diff oil with Molybdenum additive for LSD's, I assume this could affect the torque setting if you have assembled it with/without oil? (the manula refers to assembly with Molybdenum I think? I spoke to a friend who supplies car parts and he strongly recommended Millers diff oil (UK company) which I have bought and is exactly the same but slightly cheaper than redline. Mags Edited by Mags

SteveM Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 23-February-2004 Location: Scotland Status: Offline Points: 238	Posted: 08-April-2004 at 12:31
	I've spoken to two gearbox specialists - All Gears and Road&Race Transmissions. Both mentioned some parts are hard to come by or NLA. Looking through the manual, there appear to be two types of LSD fitted to our cars, so sods law, mine will be the one that you can't get bits for! With regards to oils, I have been assembling the diff with oil during testing. I spoke at length to Demon Tweaks, who suggested that Redline is fine for racing, but does need changing frequently. I've gone for Millers purely as I could get it here. In the past, I've always used Mobil 1 gear oil and I've had no problems, but I can't find anyone in Aberdeen that stocks it anymore. As to oil additives/friction modifiers, I tend not to be a fan of these "snake oil" things. It was the same with Slick 50 and the like. Fair enough, they probably do do something, but I'll stick to standard recommendations as my car is still a road legal one doing 14,000 miles a year, and not a race car doing 400 miles a season!
	Steve Scottish Cecotto

Mags Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member I Joined: 31-March-2004 Location: United Kingdom Status: Offline Points: 287	Posted: 08-April-2004 at 12:57
	Agree with you on the snake oils bit, I was just going by the references in the manual to the coating of the friction plates being molybdenum. Let us know how its goes, very interested to find out. Mags

SteveM Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 23-February-2004 Location: Scotland Status: Offline Points: 238	Posted: 08-April-2004 at 15:38
	The plates look like they are sintered metal, but as you say, manuals etc refer to the molybdenum coating wearing off with time. Maybe this coating is on the outer plate, and not on the inner one? You certainly get loads of different gear oils and additives, and as I'm not sure what is needed, I'll leave this side of things alone for the moment.
	Steve Scottish Cecotto

UweM3 Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 11-February-2003 Location: United Kingdom Status: Offline Points: 5445	Posted: 08-April-2004 at 19:41
	I am not a specialist on this subject but this guy here LSD repair has some good information about LSD's. He offers repair and upgrade for all BMW LSD's. Maybe he has a few parts in stock you need. Here is his email address: Pro-Auto@t-online.de and his name is Conny. I can help with some translation if required. Edited by UweM3
	E61 520d, slow and buzzy but my wallet likes the mpg.....