No more r3vtard assist

[Wanganstyle]

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[Jean]

Still rocking your diff! I do need new ratio though lol :)

[The Dark Side of Will]

the sider gears slide on these ramps, the stub axels are mated into the spiders with splines.

Referencing the diagrams in your TIS link:

http://tis.spaghetticoder.org/s/view.pl?2/08/69

The square lugs on the sides of #9 components are driven by channels on the inside of #12. As they are driven, they push on the cross-shafts which cause the spider gears to push on the side gears... the same way an open diff works.
However, because of that power path, the torque through the unit controls how hard the #9 components are squeezing the clutch packs. Since the normal force on the clutch pack is proportional to the torque applied to the unit, the "lockup torque" of the unit is a fixed fraction of the torque being put through the unit.
If you all the coefficients of friction, you can calculate what this fraction is.
But a rating like "max lockup torque of 500 ftlbs" can not be applied because that torque varies with how much torque is applied to the unit.

A Torsen is a bit different in that the max torque in can bias to the wheel with more grip is a fixed ratio times the torque that the wheel with less grip can deal with.

[Wanganstyle]

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[The Dark Side of Will]

Tear it apart and see how worn the clutch discs and steels are. Order thicker to make up for case wear.

Oh, you were just talking about normal wear and tear.

is it possible to calculate max lockup torque?

you can build a jig to hold the pinion flange and a side axel flange fixed and make a fixture to measure breakaway torque. or you can block wheels in the air and jack up the rear to test it field style as they do for Spec e30

Well... Wouldn't that just measure the spring preload torque? The ramps allow the torque applied to the driveline to increase the torque the clutch packs can take... Meaning that as you apply more torque from the engine, the "lockup" torque increases. This leads to the rating of diffs by "% lock", meaning that the combo of ramp angle and number of clutch disks would result in the torque the clutch packs could apply being 25% of the torque applied *to* the unit. So if you end up with 2000 ftlbs at the axle in first gear (Engine torque * trans ratio * diff ratio), the unit would be capable of biasing that torque by up to 500 ftlbs difference left to right.

[Wanganstyle]

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[The Dark Side of Will]

Most e30's are running around on melted time bombs for diffs. All the 3.25 ratios are for example, almost all 3.73 units as well.

What exactly do you mean by this?

[Jaxx_]

is it possible to calculate max lockup torque?

[ROLLingKING]

this thread is dope.

so u said something about most 3.73's are time bombs.
i want my lsd to just lock up nicely so what can i do to refreshen it or if it has to be opened up make it lock up more. add another clutch?

[Wanganstyle]

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[e30leigh]

168- small
188- medium
210- large.

If you wanted 75% locking you would need to run a custom ramp angle center section with 4 clutch discs and steels.

To compare bmw uses 4 Xlutch discs and steels for the Motorsports LSD unit but lock up is set at 40% accel and 25% deccel.

75% both ways is very high locking, pretty extreme Setup. My guys on the king of Europe pro drift circuit run something in this range (proprietary)

Also uping the Number of clutch disc Sets to 5 pairs with custom Case setup can make lockup in the 75% + range. .

The centers cannot be machined, they need to be precision ground.

Stock ramp angles are 45 degrees, with 4 disc pairs they yield 60% locking.

Do you have enough power to power over a 60% locking high lock diff? With two way action this will understeer dramatically compared to the stock setting by bmw for the car.

Are you setting up a drift car?

basically im building a car for some fun. i want to be able to drift it shall i feel the urge. i also want it to be track driven. and the odd drag day. the car will be street driven also. so a solid all rounder. and the power will be 300-350hp. turbo m20b25

[Wanganstyle]

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[Wanganstyle]

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[e30leigh]

wow this is so interesting.... how would i gain a 75% locking 4.1 for my e30? and also the 188mm is that the medium case e30 diff?

[craiggroves91]

Wangan are you capable of replacing the bearings on a diff? How hard is it?
Would you do it for some cash?