Viscious Vs Helical LSD?

[CozmoNz]

Just curious, whats the complete difference.

i know vic uses fluid, and dosnt really work until the fluid warms, thus a bit of wait.

and someone told me that the helical uses clutches of some sort?

im rather confused to be honest. someone wanna n00b it out for me

[AE85.6]

not completely sure but i THINK hellical relies more on using centafugal forces so the more shit you give it the tighter it gets, and thus no waiting time so should work just as well right from start up, but i dont know this for fact so dont hold me to it,

pretty sure s15 silvias use hellical ones as appose to viscous units so could look up s15s and see if it says anything about them ???

[Mr Revhead]

viscous.... fluid
mechanical.... clutch type
helical...... aka quaife type, uses gears to limit wheel spin.

viscous and helical are recomened for fwd, as mecanical can be a bit abrupt.

[Chickenman]

Abrupt is bad?

[Mr Revhead]

can be in fwd! mechanical is more susceptible to torque steer

[TRD Man]

viscous and helical are recomened for fwd, as mecanical can be a bit abrupt.

Not wrong, but perhaps a little bit of a generalisation.

A helical LSD is often recommended for seal use because they are gentler on the gearbox. And because they're quiet. Torque steer is not really so much of an issue with modern cars & power steering.
The level of 'abruptness' of a mechanical LSD depends on how it is set up at time of installation.
Out of the the factory a TRD Clutch type diff comes in a not too harsh state. So it can be used for street use without any problems and is excellent when a little track use is called for. It can also be tightened up until it's almost a completely locked unit which is what we would normally do with a rally car, for example. But this requires some aggression in the driving style.
They are a little noisy too. As a mechanic of mine once said, "if it's not chattering, it's not working".

[Mr Revhead]

one of my customers who fitted one straight out of the box to an ae82 fxgt reckons "it trys to rip the wheel out of my hands with torque steer"
of course he was used to non lsd on gravel so it made a huge difference.
from the cars iv driven i defintly prefer a viscous or helical in a fwd. i wouldnt want to live with a clutch type for day to day driving.
but ppls opinions on that differ.
just ask al who must have permanent whip lash from his clutch!

[TRD Man]

Most AE82's were pre-power steering weren't they. This plays a big part. I nearly broke my thumb many times even in the old EP71.
Tell him to eat more Cornies.

[10k 20v]

a helical uses the priciple of a worm can drive a gear but a gear can't drive a worm.
of course gear can drive a worm but the effort is much greater.

I have a helical in my trueno and i love it.

[Al]

just ask al who must have permanent whip lash from his clutch!

Yep imagine how it will be with a limited slip as well

[Crimson Tears]

What are you talking about? Helical is the type of gearset, as in the shape of the teeth on the gears. Not a type of limited slip diff.

Most limited slips are either a mechanical (clutch type) or viscous type.

You don't have to wait for a while for the differential to warm up, viscous fluid works in a different way to normal oils, when it becomes hotter it becomes thicker - normal oils become thinner as they become hotter. The output shafts in the differential are attached to plates that sit in the oil in the differential. When one wheel 'slips' or spins faster than the other, the plates shear the oil, the oil becomes hot very quickly and because the fluid then becomes thicker the coupling is locked and therefore both axles will turn.

Viscous limited slip differentials are smooth, progressive and quiet in operation and they do not wear as the plates do not contact each other because you're not relying on a clutch like action like in the mechanical type you are just relying on the thickness of the fluid.

As said above often the clutch mechanical limited slip diffs are very harsh in engagement and will torque steer like buggery.

[vvega]

What are you talking about? Helical is the type of gearset, as in the shape of the teeth on the gears. Not a type of limited slip diff.

Most limited slips are either a mechanical (clutch type) or viscous type.

You don't have to wait for a while for the differential to warm up, viscous fluid works in a different way to normal oils, when it becomes hotter it becomes thicker - normal oils become thinner as they become hotter. The output shafts in the differential are attached to plates that sit in the oil in the differential. When one wheel 'slips' or spins faster than the other, the plates shear the oil, the oil becomes hot very quickly and because the fluid then becomes thicker the coupling is locked and therefore both axles will turn.

Viscous limited slip differentials are smooth, progressive and quiet in operation and they do not wear as the plates do not contact each other because you're not relying on a clutch like action like in the mechanical type you are just relying on the thickness of the fluid.

sorry mate but helical is a type of lsd
torsen is the brand

look it up :d
google is your friend

v

[Crimson Tears]

I know about the torsen differential, I didn't realise it was referred to as a helical limited slip differential however.

[Al]

viscous = teh ghey

works as well as a superworn clutchpack or helical

[vvega]

worn viscous sucks
but new its works very well

v

[lil]

I have an aw11 1987 supercharged, does that have a viscous lsd? if so that might explain why at 200 000kms is doesn't feel like it has any kind of lsd at all? any way to get it to lock up better?

[Mr Revhead]

ae82 fxgts and gts are powersteer, may have been removed though.
spinach sandwiches for breaky on rally day then!

did aw11s have lsd at all? i cant find one on the epc but thats not always easy to tell for sure for lsd

[Adamal]

Spec R S15 (Turbo) = Helical option.
Spec S S15 (Non Turbo) = Viscous.
Autech S15 (Tuned Non Turbo) = Helical.

Yea, I love Silvia's

[RunningRich]

did aw11s have lsd at all? i cant find one on the epc but thats not always easy to tell for sure for lsd

Yes they did, as a factory option. I can't confirm if they just used the TRD one or not. From memory actually getting one with LSD is totally random and not recorded on the cars data plate?