Forums > General > Torsen diffs in the snow

TORSEN DIFFS IN THE SNOW
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After the usefulness of my last MX5 in the snow in 2010, I was really looking forward to driving my new one. And it gets around fine but I couldn't help but feel it's not quite as good despite the mud and snow tyres.

Thinking about the differences this morning, the only obvious one is that the new one being a 1.8 has a Torsen diff while the old one had a viscous LSD. And that brought back some vague memories of Torsens not actually working in the same way. A quick google reminded me that no grip at all on one side makes it behave like an open diff; you can apparently trick it by pulling the handbrake slightly on to add some resistance, which then transfers the torque to the other wheel.

Torsens are pretty common as LSDs in fwd cars; I guess since the handbrake doesn't work on the front wheels (in most cases) this might explain why they're not as good in the snow as you'd expect.

LFB does the same thing in a FWD. Harris did a useful vid on youtube in the original Focus RS

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Ben
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"you don't look like a fussy eater"

Ben__B said...

LFB does the same thing in a FWD. Harris did a useful vid on youtube in the original Focus RS

with a non-LSD FWD? got a link?

I remember trying the handbrake thing on my (clutch LSD) MX-5 on a little hill, wasn't convinced it had any effect. Wasn't on winter tyres.

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No, with a torsen diff

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Ben
______________________________________
"you don't look like a fussy eater"


Would explain the ITR being useless in the snow as per the other post?

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ClubLupo

JonMad said...

I remember trying the handbrake thing on my (clutch LSD) MX-5 on a little hill, wasn't convinced it had any effect. Wasn't on winter tyres.

Shouldn't have any effect on a clutch type LSD - if one wheel has zero grip and spins, the clutch will lock and the other wheel will get drive. The handbrake thing is to 'trick' the Torsen.

Matt, I think that may be correct about the ITR. Hadn't struck me until today.

MattyB_ said...

Would explain the ITR being useless in the snow as per the other post?

Megane is utter shite in the snow as well. Could be big fat tyres as well ..

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GiraffeIT.com / Installations / Support / Training
evo featured Renault Megane R26 (c) Barry Club.

andybond said...

MattyB_ said...

Would explain the ITR being useless in the snow as per the other post?

Megane is utter shite in the snow as well. Could be big fat tyres as well ..

I thought it was quite good, way better than the i10, at any rate. Must be your extra powah that's doing it!;)

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+ Non-limited edition of the Exige 240R
- Uninspiring soundtrack

What tyres did you use ?

I am on ps2 , and they are really really good in the dry , but dire in snow.

Using the clioT as I feel safer. The ABS kicks in when you look at the brake pedal in the meg.

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GiraffeIT.com / Installations / Support / Training
evo featured Renault Megane R26 (c) Barry Club.

I can't remember whether I was on PS2s or Sport Contact 5s at that point. I do seem to remember the Contis being a bit better in the wet, so maybe I was on them for the snow as well.

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+ Non-limited edition of the Exige 240R
- Uninspiring soundtrack

MattyB_ said...

Would explain the ITR being useless in the snow as per the other post?

I found it was mostly the tyres to blame on mine, they had naff all grip in cold/snowy conditions, and I often ended up with both wheels spinning uselessly on front of me. :roll:

I always thought the TorqueSensing part of the diffs operation meant it needed to be able to transfer torque to whichever side had the grip, if neither have grip it falls down ??

Barry said...

[quote="MattyB_"]
I always thought the TorqueSensing part of the diffs operation meant it needed to be able to transfer torque to whichever side had the grip, if neither have grip it falls down ??

BIC. it's not magic.
Despite LSD, I wasn't going to chance it today, but probably will tomorrow.

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Knackered old hairdresser's sh1tter

Barry said...

I always thought the TorqueSensing part of the diffs operation meant it needed to be able to transfer torque to whichever side had the grip, if neither have grip it falls down ??

It goes slightly beyond that - it effectively multiplies torque output to the wheel with grip, but what it is multiplying is the torque to the wheel with less grip. If the less grip is zero, there is no torque to multiply and 0 times anything is still zero. So one wheel with zero grip still means you can't go anywhere, not just two wheels with no grip.

Updated January 21, 2013 at 1:11 PM

hmmm, this explains the difficulties getting out of the works carpark this afternoon.

I kind of know how they work, but hadnt really thought much about it, but I know that a plate lsd as on the bmws has a fair bit of preload, enought to make one wheel on it's own hard to turn by hand anyway, certainly enough to provide some resistance on snow / ice.

I'm currently beached in a layby outside, might go out and give the lfb method a go although it might be a bit more tricky from a standing start. I was attempting to roll forwards and backwards to clear a path so I could get out in the morning but got completely stuck instead :lol:

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cheers,

Harry

Too many old sheds.

Hope your pedals are ideally placed for heel and toe in the BRMatomix, Harry :D

pass, not really driven it much in anger :lol:

I think it's suffering a bit from having 205 tyres, the 200vi only had 185s.

Quite fancy a set of bmw mini 15in steelies which are a perfect fit and a set of 175 60s

I've been out and with a bit of gentle persuasion managed to get it moving so should be ok for the morning, but will definitely give the brake thing a try at some point tomorrow.

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cheers,

Harry

Too many old sheds.

MPS excellent in the snow with winters and torsen diff. Unbelievable traction, and with DSC disabled handbraking gives you more options.

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Ben
______________________________________
"you don't look like a fussy eater"

Anyone care to explain wtf my car has? All it says is that it has an electronic diff so I'm guessing it has no diff at all and by electronic it means that it applies the brakes when cornering to help reduce understeer?

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How about not having a sig at all?

Jobbo said...

JonMad said...

I remember trying the handbrake thing on my (clutch LSD) MX-5 on a little hill, wasn't convinced it had any effect. Wasn't on winter tyres.

Shouldn't have any effect on a clutch type LSD - if one wheel has zero grip and spins, the clutch will lock and the other wheel will get drive. The handbrake thing is to 'trick' the Torsen.

ok. I guess I had no grip on both then :)

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Mito Man said...

Anyone care to explain wtf my car has? All it says is that it has an electronic diff so I'm guessing it has no diff at all and by electronic it means that it applies the brakes when cornering to help reduce understeer?

it will have a standard open diff.

an 'electronic diff' means it'll apply the brake to a wheel that is spinning, which in turn means power goes to the other wheel, nothing to do with the actual mechanical bits at all.

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cheers,

Harry

Too many old sheds.

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