LSD in layman's terms?

Dolph · 13 Sep 2009 at 23:23

Clarkey said:
JDM EP3 has an LSD, and that is of course what I was talking about.

It's an MB6 you have, never heard of these with a diff, or any UK Civic other than the limited space ship thing.

a torsen lsd was standard fit on the mb6 vti.

Nick1881 · 13 Sep 2009 at 23:35

Sorry for the late reply, just to confirm the Civic I had with an LSD was because I fitted an Integra Sir-G gearbox after the standard one started to rattle from the extra torque due to the turbo I had fitted.

I have a 2005 Saab 9-5 Aero now which from the tests I did on the ramp yesterday it seems to have an LSD. With the car in the air and in gear I turned one wheel and the other wheel turned too and couldn't be stopped. Although I can't find any info on google about them having LSD.

Dogbreath · 14 Sep 2009 at 05:42

Dr Who said:
Some used fixed, or "spool" diffs

And since a "spool" diff has exactly zero differential action, it's a bit of a contradiction in terms!

Dr Who · 14 Sep 2009 at 06:07

Dogbreath said:
And since a "spool" diff has exactly zero differential action, it's a bit of a contradiction in terms!

Well spotted, hence the "spool" as it isnt really a differential.

chipperhead · 14 Sep 2009 at 09:47

Jotun said:
Best explanation, even if it is a bit old. Skip to 1min 50.

That explains a standard differential, an LSD works the same but the gear in the middle will only rotate up to a maximum speed so there is a limit in the difference between the speeds of the 2 wheels turning.

That's a great video, something I've never really thought about or understood before.

Jonnycoupe · 14 Sep 2009 at 21:08

rypt said:
And a 48bhp Micra needs all the grip it can get while driving along at 28mph ...

What 48bhp Micra comes from the factory with an LSD?

rypt · 14 Sep 2009 at 21:17

Jonnycoupe said:
What 48bhp Micra comes from the factory with an LSD?

You missed the point

Dogbreath · 14 Sep 2009 at 21:38

Dr Who said:
Well spotted, hence the "spool" as it isnt really a differential.

I was commenting more on the "diff" part of "spool diff". More of a crown wheel mounting device really

Jonnycoupe · 14 Sep 2009 at 22:08

rypt said:
You missed the point

Atleast I had one.

rypt · 14 Sep 2009 at 22:21

Jonnycoupe said:
Atleast I had one.

So did I, that low power FWD cars that are A-B mobiles driven by old grannies do not require an LSD as they will not be ragged about at their limit on the track/road.
And since the majority (>75%?) of FWD cars fall into the above segment my statement that most FWD cars do not need an LSD stands and is correct.

Clarkey · 15 Sep 2009 at 00:33

rypt said:
So did I, that low power FWD cars that are A-B mobiles driven by old grannies do not require an LSD as they will not be ragged about at their limit on the track/road.
And since the majority (>75%?) of FWD cars fall into the above segment my statement that most FWD cars do not need an LSD stands and is correct.

What is your point? The above applies equally to RWDs.

mattyprice4004 · 15 Sep 2009 at 00:58

The Ti's LSD made a huge difference on the first Yorkshire meet - I got a bit over-eager on a hairpin and it didn't half cut the understeer! Smiles all round

Not good for tyre life however

rypt · 15 Sep 2009 at 01:19

Clarkey said:
What is your point? The above applies equally to RWDs.

An LSD would help RWD in the wet though more than it would help FWD, besides most RWD cars make over 100bhp really

Jonnycoupe · 15 Sep 2009 at 23:13

rypt said:
An LSD would help RWD in the wet though more than it would help FWD, besides most RWD cars make over 100bhp really

How does it help most of the time?

RWD doesnt have huge issues with traction. But FWD the difference is massibe, you only have to drive a Civic Type R and a Dc5 to see how much more grip there is, the Civics just light up the tyres as pretty low throttle openings.

You have to be gunning a RWD to get wheelspin IMO.

Dr Who · 15 Sep 2009 at 23:25

Jonnycoupe said:
You have to be gunning a RWD to get wheelspin IMO.

Pretty true, weight transfer gives you increased RWD driving traction, just like it does at the front under braking.

LSD helps FWD cars a lot with accelerating traction because they dont have the benefit of weight transfer to the front!

[TW]Fox · 15 Sep 2009 at 23:46

Jonnycoupe said:
You have to be gunning a RWD to get wheelspin IMO.

This. I rarely find the lack of LSD in my car a problem (Despite BMW's insistence that DSC is an electronic LSD I doubt very much it is as good as a proper one) and I need a wet road or to be driving like my trousers are on fire to get wheelspin really. It just never happens in normal driving.