How to tell if LSD is worn?

[Two_Sheds]

I advertised an LSD for sale as worn, but I've chatted to a few people and now I'm questioning whether or not it is. The previous owner bought the LSD off a zone member, I chatted to him today and he said it was in great condition, and I'm sure I've not used it enough to have worn it out already.

Basically, when drifting (its a drift/track car), it wants to pull me out of the drift too soon like an open diff and the inside wheel spins up (hence why I thought the clutches might be worn), but it occured to me that as E30 LSDs are about 25% locking (?), am I right in thinking that that should mean that a maximum of 75% power can be sent to the wheel losing traction - more than enough to make the wheel spin up and smoke, but not enough lock to keep me in the drift. It is, however, superbly grippy when track driving, the car always feels planted and goes where you point it.

Is there any way of testing to see if its working correctly?

I think I may have misinterpreted what the LSD should be doing while drifting, so assumed it was broken. I need to find out what sort of state it is in, if its in good condition then I'll either be leaving it on the car and using it as a selling point or selling it on here again (but with a readjusted price tag ). If it is in fact FUBAR'd, then I shall relist it for sale as such.

[mrLEE30]

a track and drift car are set up completely different, a track you want some slip to allow the wheels to turn the corner without binding up and causing friction (as the outside wheel travels further) but allow the power to be applied to both wheels (admittedly unevenly as the wheel on the inside is light and thus grip is down) for maximum traction and thus drive out of a bend so a compramise is met hence the limited slip diff.

for drift you need the diff to be as solid as possible, so welded, as you are not concerned about the tyres dragging round the bend as they are generally spinning and thus grip is lost anyway.

not sure how a layman would test a diff without special equipment, ideally you would turn one side of the diff with a fixed torque, say 1Nm and brake the other side, the amount of braking should be 25% (0.25Nm) of the torque required to turn the opposite side (on a 25% LSD)

[hoshy]

I've got a slipper on my iS and it won't sustain a drift very well either. I also thought mine was buggered because of this but after some enthusiastic "grip" driving I noticed that it is locking up properly to drive out of tight corners and is less snappy than open diff. I suspect you're right that the 25% lock isn't enough torque to the driven wheel.

I think to test, get out and waste some rubber. Try leaving a number 11 up the road and try some donuts. My iS power (lack of) and my skill (lack of) make it tricky to do small radius "tight" donuts but I could just about keep a wide radius drift/donut going on shitty tyres at 40odd PSI.

[Dan318-is]

Is the diff on the car? You could try 'chibsters (Demlots) torque wrench trick although im not 100% how he said to do it. Somethinkg like put it up to 80nm and see if the clutch packs lock? send him a pm and ask him how

hth

[Two_Sheds]

Cheers guys, you've kind of confirmed what I thought, think I'm probably going to leave it on the car - will try and do the number 11 test later!

Heres a video of it in action, you can see the inside wheel spinning up, bit its not spinning completely:

[hoshy]

there's lots of smoke from the unloaded wheel but any from the driven which would suggest to me that there's not a lot of power getting to it but if it's the right amount for a std e30 lsd I don't know. Looks like you got a few nice drifts going so I wouldn't say it's completely open.

Think we need more of an expert opinion though. Karan? Zaust?