BMW E30 LIMITED SLIP DIFFERENTIAL TUTORIAL

[1D0N]

You say you can't stop the other output flange from turning because of the locking unit. Actually this is not the case, as no load is applied, so there is no locking action. What it is is the preload on the clutchpack. If you were really strong and could overcome the preload, you would be able to stop one side.

[brayt0n]

or you could get a open bmw diff, and apply the welder to it and always peel 2 :) muuuch cheaper

[acemotorman]

zzzzzzzzzzzzzzzzzzzzzzzzzzzzz

[LoomisLoftis]

there's one way, two way, and 1.5 way limited slip. You didn't address those.

[tomtom3245]

@LoomisLoftis

You're right, this is a "symetrical" lsd aka 2 way, same lock-up percentage on acceleration AND overrun. The two slopes inside the unit on which the axes compressing the discs slide have identical angles. A 2 way lsd is the best for drifting but on fast front wheel drive cars a 1 way is the preferred route so as to limit understeer when you let your foot off the gas (if you ever do xD )

[mburns212]

Hi tom, good info. do you happen to know anything about the e46 330d differential? I am looking to retro-fit another BMW LSD unit inside mine. Problem is i don't know if any fit!

[tomtom3245]

@mburns212

I have no idea but chances are it should fit.

Grab an M differential from an e36 M3, Z3 or e46 M3. The LSD should fit without any problems though you will have to have the clearances properly adjusted!

There are many on sale on ebay.de, look up bmw sperrdifferential

[doriftomasta]

@mburns212 no bearings and size of the gears inside the diff are different + gearbox has different output speed than supposed to

what you can try is to put the gears inside the diff somehow tighter together thats how a 30-50% solid diff works

[tomtom3245]

@doriftomasta

Can you expand on that? These work without friction discs?

Do you have a link?

[jeroen3nl]

sper mostly means a solid axle but in germany spur means the gear around the diff itself

[tomtom3245]

@jeroen3nl

Ok, thanks for the info!

[Losti87]

Nice description!

btw your almost right about the S, it stands for the german therm "Sperr" which means "lock"

sry for beeing a smart ass^^

[tomtom3245]

Thank you! Yes, I found out soon after the video was posted that sperr means lock...!

No worries for smart assing ;)

Go e30s!!

[imjustrobert]

you lucky bastard with your 4.27! haha

one question, can i take the diff out without having to remove the wheel hub? (the 30mm nut and the puller) the bently manual says to remove this, but i found a website that says DC the driveaxels from the diff then drop it via taking off main bolt that holds the diff on.

[tomtom3245]

No, you don't have to remove the wheel bolts, it will however make access easier if you're working on the grounds. Having the wheels off gives you more room to reach the bolts holding the drive axles. Undo those first, then move on to the bolts connecting the input flange to the propshaft and finally the 4 bolts holding the diff to the rear subframe.

Yes, LSD 4.27 is a deadly combo!

Good luck!

[tomtom3245]

I meant wheel hub... You only need to do that if you're in for a change of wheel bearings.

[MrEmCom]

Very god guide!

[tomtom3245]

Thanks a lot!

Hope it helps!

[MrEmCom]

Not really, I already knew that, but you explained it very god, best regards from Sweden.

[tomtom3245]

very good is what you mean lol!

Well I did the best I could that's for sure!

You must be having loads of fun with a lsd up in Sweden!

Regards from France!

[MrEmCom]

Yes of course i did :$ Yes, in the winters its very fun :) Check out my Omega 3000 whith LSD, 45% Lockingeffekt. =D

[almaster666]

Nice! 45% lock up that's good. I'm changing mine up to 50% from 25% on my Alfa Romeo!

[Duppytube]

@tomtom3245

what ur from france ?

how it come u dont have this ugly french accent when speaking english ? :D

bonne video ;)

[tomtom3245]

Hi Duppy!

I'm actually Franco-British but I've lived in Seattle and the SF Bay Area for a number of years!

Regards

Tom

[dieselscience]

In this context, "Sperrdifferential" means 'locking' (or lockup) differential. These are the helical gear type.

[tomtom3245]

helical gear... Not sure what these are, these have friction discs inside. Thanks for the translation!

[dieselscience]

Actually, they don't have friction disks at all, they have helical gears that transfer torque, hence sperr and not 'kupplung.' They're sold in UK as Quaife diffs. They work much smoother than disk types.

[tomtom3245]

Oh yeah sure I know which ones you're talking about, Quaife yes, these are awesome... Quaife is a UK brand, and I think some cars come standard with Quaife diffs, offroad vehicles but very few... I thought you were talking about the stock e30 lsd which have friction discs, and it's a 2 way!

Regards!

[tomtom3245]

Wait, which ones are you really talking about because I am absolutely positive that these have friction discs inside, I have seen them!

[dieselscience]

That must be an older one, like '86 or so? I have a '97 with helical gears, they've been putting those out for several years now.

[garthrallysport]

ATB diff? I have a clutch type in mine, and I though they all came clutch type standard.

[shortyruler]

I don't think that it has a "Sperrdifferential"!

And not every BMW diff is locked, not even 25%

But there's a additional lock available with a 25% lock for about 350 Euro!

If you want it, the part nr. is: 33 14 1 210 493

[tomtom3245]

Thinking about it, if your car's from Canada there's a chance you might have it with all that snow you get!

[tomtom3245]

You don't need a jack for that, unless you car is lowered just crawl down underneath it, the S is fairly visible as you can see in the vid, little harder to spot on the tab. If you car's lowered or you just don't want to bother, drive the rear of the car up a sidewalk, APPLY the parking brake!!! and you should have a good view of your diff!

[testacorsa150]

Nice.

Just a little correction though: The S stands for "sperre" - which means "lock" or "locking".

The BMW diffs have 25% limited lock.

The "M" for motorsportones should have either 40 or 75% limited lock.

[tomtom3245]

Thank you!

That's right, BMW Motorsport differentials have higher locking, I believe the spider gear carrier had different ramp angles built into it so that you could easily change your locking ratio without having to actually change the carrier!

I found out later on that "sperre" means locking, sorry about that!

[testacorsa150]

You are welcome :-)

No problem about the meaning of "sperre" - if you are in doubt about any other bmw translation - just let me know. Ofcourse there are many translations sites, but specific terms from the automotive industy can be hard to find.

Sounds sweet that you could change the ration without the carrier.

To bad they are hard to come by and cost a small fortune.

[tomtom3245]

They do cost so much... I guess it's easier to just have someone customize your own carrier rather than buying a Motorsport diff, I don't even know if you can still buy them from the dealer... It's also such a shame that so very few cars come standard with an lsd nowadays, you always have to go for the top of the line M cars or the biggest engines in the line-up... Totally transforms the car, I just couldn't believe I was driving the same car when I put it on!

[shortyruler]

I just looked it up!

The US M3 3.2 also has an 25% Sperrdifferential!

[tomtom3245]

Yes, all M cars have an lsd

[StarsMarsRadio]

do all bmw e30's have a limited slip differential? to be more specific. a 1989 325i, would that have a limited slip or do you know?

[tomtom3245]

It depends but no, the lsd didn't come standard on all e30s. A top of the line US spec 325i has it for sure apparently, a lot of US e30s were fitted with the lsd, I think they came standard on certain engine versions but for others it was an option. I guess the American public was more used to going for that option when buying a car because they were used to buying Positrac or SureGrip options on earlier US cars.

[tomtom3245]

Again, one way to know is to lift the whole rear end of your car and turn one wheel while watching the other one which should spin in the same direction. Easier way to do it is to check for the S on both the outer casing and the small metal tab.

[StarsMarsRadio]

its a long drive to the one im looking at getting. its a 2 door 89 325i. but if it was an option i doubt it had it. it has cloth seats so if they didnt go out of the way for leather i doubt they checked off limited slip