V5

Can anyone explain (in farly simple terms! ) about LSDs, please. I've a limited idea (groan...pun intended) about what they do, but could do with a proper explanation.

TIA
Iain

mik

you should get what you want by clicking here

Barnaby

A quick summary would be a differential allows the wheels to spin at different speeds. A limited slip diff moves some torque to the slower wheel if the difference is big enough.

So if your inside wheel starts to spin in a corner the outside wheel can get more torque 'pulling' you into line.

MarkO

The howstuffworks explanation was much better, Barnaby.

V5

Cheers guys, will have a read of that.






After work, of course!!

ScoobyJawa

(biting my lip )

Barnaby

Doesn't suprise me Mark. I was hoping somebody would put me right if I was getting it wrong

Had a chance recently to do a practical trial on the front diff.
In all the heavy rain I went to an off public road area I know with a newly tarmaced roundabout. Tried driving into the roundabout faster and faster until the front started to wash out. Then tried it again and kept my foot down even when the front started to slide. To my relief the front diff did kick in and pull the front around a bit. Think this needs a lot of practice though, and not something I would dream of doing anywhere near other cars

donaldm

does p1 have slip diffs..?

Barnaby

It certainly does at the back, not sure about the front though?

Andy W

Viscous coupling sliipy diff in centre also

KungFuMonkey

Most four wheel drive cars will have a limited slip diff in the rear and centre diff with an open front diff. The open diff at the front helps to reduce the plow on understear effect.

On most subarus etc it's a viscous diff centre and back, although some of the sti's i think have a viscous front and centre and a plate type on the back. They will understear more on turn in, but will pull out of a corner much better this is mainly for rally purposes as you throw it sideways comming into the corner and are really looking for max traction on way round and out.

V5

Cheers guys.

So, the way I understand it, if you encounter a low-grip-situation, the LSD will feed some of the torque to whichever wheel can take it. This meaning that it will help you go in the direction you want.

This is easier to picture with FWD - does the same apply with RWD? Just wondering how it would affect/help things if the tail steps out mid corner.

Edited to add - I guess I'm after an explantion of the benefits as well. Why is it worth paying the extra on my wife's Mx-5?

Cheers!

[Edited by V5 - 10/22/2002 1:34:27 PM]

Barnaby

I would think exactly the same logic applies to a rear limited slip diff.

You are in a tight corner with a bit of throttle on. The inside rear wheel is getting as much power as the outside one, but has a lot less weight on it. So it starts to spin up.

With no limited slip this would just get worse and worse with the inside wheel spinning freely and the outside one getting less power. It could almost feel like a mid-corner lift-off.

But with the limited slip diff the power gets routed to the outside rear wheel. This then forces the car to turn sharper or sets up more of a full rear drift as both wheels spin up. Much more balanced and controllable.

I think this is how a lot of traction control systems work. They brake the inside wheel and so force more power to the outside one and so force you around the corner. And if you start to oversteer too much they reverse this so that you balance up.

That's my take on it, but I am no rear-wheel drive expert!

ScoobyJawa

Indeed - like I said, its well worth having over the standard 1.8

V5

I know you said that, and I didn't disbelieve you. I just wanna know WHY???

ScoobyJawa

Well I told Jennie that too Not my fault if you weren't there!!!! lol!!

stockcar

very basic terms - if one wheel is spinning on snow and the other has grip an LSD will allow both wheels to turn at the same speed (ish) - however this depends on the amount of "LOCKING" built into the diff unit (varies from about40% to 100%)
alyn - as performance

darkblueturbo

RC Developments have a couple of videos of a couple of Evo6's (sorry) going round a twisty track. 1 standard and one with a slippy diff at the front.