How can you Tell if a LSD is knackered?

[antnicuk]

I have just been watching the Rotorstock DVD and there is some footage of me doing my only run.  The commentry guy noticed but no one has ever mentioned it to me.   I was only spinning one wheel during the burnout, so i only warmed up one tire.........

I spose it means i could have done a better run but i am still running the same diff and other than finding it really difficult to drift it which i put down to my poor driving skills it seems to work fine!

I will have to check out how many lines i leave next time i take the car out

Its a diff from an Efini model, does anyone know if its a clutch type or mechanical type


Can they be repaired?

[RemarkLima]

My understanding is if you jack up both rear wheels, then spin one, with a open diff they should spin opposite ways (i.e. you spin one forwards the other spins backwards) but with a LSD they\'ll both spin the same way.

Now I don\'t know if the LSD goes then it reverts to an open diff IYSWIM...

The other thing I\'ve always found with LSD\'s, if you turn a sharp corner at slow speeds when it\'s still cold it\'ll lock up real easy and you\'ll hear / feel the inside wheel spin, it may help.

[nikp]

The other thing I\'ve always found with LSD\'s, if you turn a sharp corner at slow speeds when it\'s still cold it\'ll lock up real easy and you\'ll hear / feel the inside wheel spin, it may help.

That wouldn\'t happen with a mechanical torsen type LSD. And i think that is what the FD\'s have.

[RemarkLima]

That wouldn\'t happen with a mechanical torsen type LSD. And i think that is what the FD\'s have.

I\'m now to the FD\'s... But I\'m pretty sure I can get my inside wheel to spin pretty easily when cold, just doing to the full lock turn out of my road with a bit of throttle, not a lot but a bit.

I guess spin is too harsh a word, more just skip a little as it\'s locked... It\'s nowhere near as bad as my old MR2 SC, the diff on that would basically be locked solid until it warmed the oil a bit! Would get a full skidding noise just turning a corner!

[Ricco_04]

I\'m now to the FD\'s... But I\'m pretty sure I can get my inside wheel to spin pretty easily when cold, just doing to the full lock turn out of my road with a bit of throttle, not a lot but a bit.

I guess spin is too harsh a word, more just skip a little as it\'s locked... It\'s nowhere near as bad as my old MR2 SC, the diff on that would basically be locked solid until it warmed the oil a bit! Would get a full skidding noise just turning a corner!

I used to get that with bad alighnment!

[RemarkLima]

It could be aggrivated by that as I\'ve got some different higher suspension on the rear while their being refurb\'d... But then it does pretty much stop when it\'s all nice and warm...

But it could well be something with my car, as it\'s new to me so not sure of all the in\'s and out\'s as of yet!

[antnicuk]

My understanding is if you jack up both rear wheels, then spin one, with a open diff they should spin opposite ways (i.e. you spin one forwards the other spins backwards) but with a LSD they\'ll both spin the same way.

Now I don\'t know if the LSD goes then it reverts to an open diff IYSWIM...

The other thing I\'ve always found with LSD\'s, if you turn a sharp corner at slow speeds when it\'s still cold it\'ll lock up real easy and you\'ll hear / feel the inside wheel spin, it may help.

when jacked up both wheels spin the same way as they should, even since RS3, i\'m jusr not sure why only was spinning then

[TRex]

when jacked up both wheels spin the same way as they should, even since RS3, i\'m jusr not sure why only was spinning then

 You either have one or the other... That is, a Viscious LSD or Torsen LSD.   "Or None!"

  To test a \'V\'LSD put a torque wrench on the hub (wheel in the air) and turn 90 degrees with about 11/12 ft lbs of torque (car in gear). This should take no less than 4 seconds. If less then you have either an open diff or the \'V\'LSD is toast.   Another test for a good \'V\'LSD is to jack up the rear with both rear wheels in the air. A good \'V\'LSD will turn both rear wheels in the same direction when manually turning the drive shaft. The open unit (or toasted VLSD) will turn the wheels in the opposite directions
 

The \'Torsen\' won\'t always turn both wheels when you turn the driveshaft, sometime if they are cold they will. One way is to take out the fill plug to see the Torsen gears which is hard to do because of the angle.
Another way is to attempt to turn both half shafts in the same direction at the same time (car/tranny in neutral), "Can\'t be done with a Torsen."

 The foolproof way is to pull the drive axle, If you don\'t see a bar and can see directly thru the diff. It\'s a Torsen. If there is a bar, (spider gears) it\'s open.

 Bonus info.
 Clutch pack type LSD check...

 -Raise one rear wheel -Put tranny in Neutral -Put a torque wrench on a wheel lug nut of the raised wheel -Rotate the wheel with the torque wrench and note the required torque, This slips the clutch inside the differential and the amount of torque required to do this can be used to determine the condition of the clutch.
 Different units have different torque values (dependant on clutch size and spring load) One common rule of thumb is anything lower than 15/20 lb ft indicates wear and tiredness of the LSD.........

[Bramble]

I have just been watching the Rotorstock DVD and there is some footage of me doing my only run.  The commentry guy noticed but no one has ever mentioned it to me.   I was only spinning one wheel during the burnout, so i only warmed up one tire.........

I spose it means i could have done a better run but i am still running the same diff and other than finding it really difficult to drift it which i put down to my poor driving skills it seems to work fine!

I will have to check out how many lines i leave next time i take the car out

Its a diff from an Efini model, does anyone know if its a clutch type or mechanical type


Can they be repaired?

I use mechanical type (torsen). I get exactly the same problem, it even caused some severe handling problems at silverstone including a 100mph spin. Timrxmotors also uses torsen and gets the same problem. The boys there reckon its just too much power for the cog type. I have even taken mine apart and there looks visually like there is nothing wrong. Thing is I know there is. I am going for a clutch type diff to sort the problem.

Ant.

[antnicuk]

mmmm,  that would explain things!

[Timrxmotors]

I have a clutch type lsd,and when I found I was only spinning one wheel during a burnout,I just used more rpm,problem solved,both wheels spinning.

[antnicuk]

cheers guys,  i think thats the case with mine.   The burnout i did was at very low rpm and when i have tried it since it spins both wheels.  Also, looking at the video, i spun both wheels on the off take.

[oldone]

Cant you adjust the friction lockup on the diff.i.e 30%,40% etc.?:Typing

[antnicuk]

Cant you adjust the friction lockup on the diff.i.e 30%,40% etc.?:Typing

if only i had your wisdom, then i probably could...:god :god

[Bramble]

Cant you adjust the friction lockup on the diff.i.e 30%,40% etc.?:Typing

How? Its just a bunch of gears, nothing you can adjust as far as I can see