LSD rebuild and ratio change

[Templ8e30]

Small case has 6 bolts on the back plate

Cheers,

Iain T

[DanThe]

Large case also has 8 bolts on the rear cover, but the drive shaft joints are much larger. The side covers have 8 bolts each unlike the medium case diff which has 6



You cant see all of the bolts on this large case but you can tell from the pattern there is 8

[Brianmoooore]

Large case looks like something that belongs on a truck!

[DanThe]

/\ easier explanation /\

[odbod]

very good lots of useful info. Cheers

[mybmw6]

Are the pressure rings hardened? I'm getting a machine shop to change the ramp angles while I'm getting a LSD centre put in and the guy doing to work wanted to know. Cheers Matt

[stuartgallafant]

i should imagine they're probably tempered steel, but they may just be high grade steel or something?

does it not tell you on the metric mechanic site?

[mybmw6]

I've read it pretty thoroughly (the diff section on the Metric Mechanic website) but I didn't see it in there. Not getting the work done for a while so I'll have a look on the net and see if I can find out. I'll post if I do. Cheers

[stuartgallafant]

did you fint out what you were enquiring ^^^^

[mybmw6]

did you fint out what you were enquiring ^^^^

Hi Stuart, no not yet.

[Godspeed]

I bought a plate kit for the Atlas axle to have fitted in a diff I wanted rebuilding , but in the end I bought a brand new 75% lock diff from BMW motorsport , so if any one wants a brand new plate kit , and a second hand LSD unit to fit it all in , its all yours for £200 , give me a ring if your interested 07837 381608

Simon , I doing Longcross this weekend , are you going , the TV crew for men and motors are there to be shown on sky in the near future , going to kick some WRC arse

Cheers Ian

[odbod]

What Ratio is the diff you have? Is it a complete unit (Casing and all) or just the LSD bit? Would be interested.
Simon

[Godspeed]

Its just the LSD unit , but I do have a 2:5 CW & P you can have with it

[stuartgallafant]

godspeed, would you sell just the atlas kit?

how much was the 75% unit?

[Godspeed]

The Atlas kit cost me £140 , so would sell for that , the 75% unit cost £700 from Germany

[stuartgallafant]

The Atlas kit cost me £140 , so would sell for that

i might be interested in this, where did you get it from, may i ask?

the 75% unit cost £700 from Germany

ouch!!! was it worth it?

[Godspeed]

I got the kit from a rally contact , dont know where he got it from

Yes it was worth it for the complete unit , along with the brand new 5-44 cw & p at £700 , and brand new shafts and bearings ect for £500 ,

[JazzMan]

Good info chaps, after reading this lot it seem like a better idea to get a BMW diff and rebuild rather than go for the rather expensive option of an ATB!

[stuartgallafant]

Jazz, whats an ATB?

also, what exhaust manifold you got on that little monster cart of yours???

[odbod]

An ATB (Automatic Torque Biasing - See Focus RS or Megan F1 R26 special edition) essentially a quaife diff, OBX do a cheap copy and you can get them from the states. They work by a series of interlinked worm gears with a spring in the middle, rather than by friction plates.
They are good but expensive, they also have different characteristics but not sure you would be able to tell on the road.

[odbod]

Godspeed, how much for the LSD unit only? and just to be sure it is a type 188 (medium) isn't it?

[stuartgallafant]

yeah, i heard about these! worm gear setup rings a bell

[JazzMan]

One of these: http://www.quaife.co.uk/What-is-a-Quaif ... fferential they are pretty expensive. Someone who know a heck of a lot more than me about how they work explained it to me and it sounded very good! I need to spend some time reading about them myself.

But basically you buy the unit and install it inside of you existing diff instead of the clutch plates and other gubbins!

[M3Compact]

brand new 5-44 cw & p at £700

Bargain Ian!

[MrDazzle]

ATB...

Put simply: A 'standard' LSD works on speed differential. It splits the torque proportionally based on the speeds of the wheels, the faster wheel gets the less torque. I.e. it is assumed that the wheel spinning faster has less grip because it's got spinning.

An ATB uses a more sophisticated set-up to 'sense' which wheel has more grip. The wheel which is hardest to turn gets the most torque, i.e. it is assumed that the wheel that is hardest to turn has the most grip.

[stuartgallafant]

so has anyone got anywhere with this yet?

i had loads of enthusiasm when the thread first started but lost it a bit still well up for giving it a go though!!

[Templ8e30]

I've changed my ratio from 3.64 to 3.91 by installing the LSD uit into a 3.91 sport diff.

I've left the LSD at 25% lock for now though, never driven with an LSD and don't want to make it undriveable.

I got a quote of £85 from http://www.driveandtraction.co.uk/50601.html for the atlas rebuild kit (set of 4 plates inc wavy plates).

Does anybody have experience of the difference between the standard 25% lock and the 40% Alpina lock up ?

I'd obviously like to do this before fitting the diff but as I said I don't want to make it a hairy drive in the wet (it is my daily driver and will soon be transporting a newborn about in it ).

Cheers,

Iain T

[stuartgallafant]

iain, im not sure its the wavy type plates that are needed

[gareth]

sounds like a good price, if it's the right kit

[stuartgallafant]

i thought it was the standard type plates that simon suggested using

[Templ8e30]

I asked for a price for the atlas rebuild kit, the reply was £85 for the rebuild kit with wavy plates

I would have thought it includes a set of 4 coated plates/4 friction plates and a set of wavy washers for adding preload.

I'll confirm with him.

Cheers,

Iain T

[stuartgallafant]

that kit defo sounds right, but i could of sworn that its not the wavy plates that are needed? i think its on page 2 or 3 of this thread?

hth

[gareth]

here's another place with what seems to be the right bits.... (atlas axle parts)
http://www.gearboxman.co.uk/pscwpinion.html

[stuartgallafant]

nice one gareth, although that looks like its only a two plate kit, and its also £13 more than the other place

but i maybe wrong...

[ibriggsy]

Did the guy with the diff and atlas set sell it or is it still available? Anyone know?
Cheers,
Ian