LSD Question - 1 way, 2 way, Viscous
 

Alright, i just got my '83 GSL a few weeks back and finally got it out in the parking lot for a little fun. It leaves 2 tire marks, but one is stronger then the other, and i can also feel more grip coming from one of the wheels. I know mine is equipped with an LSD, but i was wondering if anybody knows if they're a Viscous LSD, 1-way LSD,or a 2-way LSD?


I searched the forums/internet but i couldn't find anything that told me exactly that.

Thanks

It is a clutch type LSD.

Clutch packs. Viscous didn't show up until the S5's.

are you sure it is a gsl or gsl-se rear end? i have seen/heard of non-lsd rears smoking both rear tires...when you shift 2nd heard does the rear end brake lose? if so it is for sure lsd

and they are clutch...you can do a few tricks to it to make it lock up harder wooot

cheers PaTricK

Any rearend can leave 2 strips, if both tires have equal traction.The LSD forces both tires to spin regardless of if their traction capabilities differ.
The clutch type LSD comes in two basic flavors,thankfully ours is the better of the two.

One type is the preset clutch LSD,often call the Track-lock by Dana Spicer.It has preset springs forcing pressure on clutch discs.The discs are splined to the axles and exert a force which keeps both axles locked to the carrier.But since this type of LSD is passive,the discs cannot increase their hold on the axles.If the traction forces between the two tires exceed's the grip applied by the springs and clutches,then one tire will spin and one wont....and your back to an open differential.When the discs/springs wear out,their grip decreases and the LSD is basically useless after 50-75K miles,typically.

The other is the torque activated clutch LSD,often call the Power-lock by Dana Spicer.It uses input power to drive a set of torque blocks and spider gears,which ride up a ramp and exert clamping forces on the clutches which are splined to the axles.The more power you feed it,the harder it pushes and the tighter it grips.The clutches are also preloaded with spings,much like the passive LSD,but this pressure is minor and is exponentially increased by the pressing of the torque driven blocks.
Even if the springs and discs become worn and weak,the forcing apart of the torque blocks by input power,will cause both tires to recieve power and stay in traction.This is the case with my old SE rearend.Its quite loose and has almost no preload,but when I put 300HP into it,both tires will spin regardless of if one is wet or in gravel,or if Im spinning a right or left hand donut.

1-way and 2-way just reffers to when/how the torque driven LSD locks up the two axles.The degree and frequency of lockup is determined by the profile of the ramps which the shafts ride up.The steeper the ramp,the more power is required to lock things up and the quicker it will lock.Also,if both sides of the ramp are the same angle,the LSD will work on deceleration as well,such as when you are braking when approaching a turn.Having too much lockup under decel can upset the rearend and cause problems with cornering.This is why many aggresive LSD are only aggresive under power,and is the main reason why 1.0 - 1.5 - 2.0 way LSD's exist.Different characteristics for different drivers,tracks and cars.

Viscous LSD's suck and are generally used for smooth,un-obtrusive operation,much like the Track-loc LSD.They dont chatter and require no special gear oil additives.They also have clutch discs in them,but they are encased in a sealed carrier filled with a special silicone oil.The oil reacts to sheering forces between the two axles and it momentarily changes its viscosity when there is slippage.When the oil becomes thicker,its causes the clutch plates ride together,increase power transfer and reducing slippage.Its nice for center differentials on AWD cars and for cars where a strong,positive LSD isnt needed.

yeah it is for sure an LSD, and yes it does break loose in 2nd.

i was just wondering if it was a viscous or something lame like that. Thanks

Now I want to go a donut.... I primarily do left hand donuts, is this because I am left handed? I must go do some right hand ones. I may be missing out on something.... :moon:

Actually,there may be something to that.Im also more comfortable going left,being left handed.Not that I do a lot of donuts or abusive type stuff these days,but I used too with the old N/A engines.

Theres a motorcycle equivelent to that, as well.Most riders are more comfortable on left hand sweepers since we drive on the right side of the road and on a left turn,you are furthur out and have better visibility. Righthand turns tend to be tighter,with more blind spot.The proof is on the tires,if you look,most sportbikes will have wider "chicken strips" on the right side of the rubber....

The driveshaft torque tries to pick the right side tire off of the ground. Doing left-hand donuts loads the right side of the car so in theory (and in practice) both rear tires see more equal loading than if you were to try it righthanded.

Even with a limited slip you can pick up the rightside tire and get one-wheel spin. There's only so much that the clutch packs can do to equalize axle speeds.

Hmm.. a thought. With shorter gears in the back, the driveshaft torque is lessened for a given torque/RPM at the wheels, so a taller trans gear and a shorter axle gear should minimize rightside lift for a given acceleration. Must ponder this further. :)


But regardless, you can and do get both tires spinning with an open diff. An open diff doesn't "send power to only one wheel" like some people think, it just splits torque equally to both wheels. If one tire spins, then it's putting minimal torque to the ground, so the other tire also sees minimal torque. But if *both* tires are spinning... :) I dragraced for a year with an open diff and never had any real one-tire-only problems except for the burnouts. Main advantage of the limited slip for drag racing IMO is that it's stronger due to the four-pinion design. If your corner weights aren't right you can still get one wheel spin with a limited slip, once you overpower the clutches!

Viscous diffs suck rocks through a straw and don't deserve mention for performance use unless it's in an AWD system where wheelspin is unlikely. Likewise, Torsens aren't even limited slips, they are open diffs, they just apportion torque as a *ratio* instead of 1:1 like a standard bevel-gear type diff. If one tire is in the air or on glare ice, the tire with traction will see maybe 2-3 times the torque the other side gets, but 2-3 times zero is still zero :)

How can i know if My diff its lsd or not viscous or not if its not on the car cause i have some on My garage floor maybe one of them its an non turbo lsd...

Though it has nothing to do with anything, I mostly do left-hand donuts and I'm right-handed. :dunno:

Zombie thread needs... BRAINS!!!

Lol, I didn't even notice.

I look at it like this (donuts) - if you spin left and hit something there is plenty of car to absorb the damage before it gets to you. On a right hander, there isnt much at all before your head is smashed in.