Quick Q about LSDs
Discussion
Morning all,
My next door neighbour bought a Cooper S a while ago. The other day he saw me fitting a Quaife ATB diff to my Westfield and told me that his Mini had an LSD fitted from new. He didn't know which type of diff it was though.
So, is the optional factory LSD viscous, torque sensing/biasing or a plate type?
Cheers
Paul
My next door neighbour bought a Cooper S a while ago. The other day he saw me fitting a Quaife ATB diff to my Westfield and told me that his Mini had an LSD fitted from new. He didn't know which type of diff it was though.
So, is the optional factory LSD viscous, torque sensing/biasing or a plate type?
Cheers
Paul
(i had it described to be as being a..) It's a worm drive ATB type LSD that (apparently) never locks 100% (Quaife ATBs do though don't they (the focus RSs 'problem').. rather than a gear type like an integra type-r
millions of people claim that you can't get MCSs with an lsd but you can! i am not sure if it came in with the facelift ('phase 2') or the power upgrade ('phase2.5') (as an option). mine's a 170bhp 'phase 2.5' one. it's got dsc and as part of dsc you get the slippery diff. you could buy it on its own for about £100-150 or with dsc for c£250..
in the dry it's awesome even on runflats you can tell the difference. in the wet it's good too but i really noticed when we were coming out of winter and it was a bit damp and there was all that cr4p on the road that it torquesteered.. but not too bad.
GPs have it as std otherwise it's an option (althought the later line built JCWs may have had it chucked in for free..? not sure about this).
millions of people claim that you can't get MCSs with an lsd but you can! i am not sure if it came in with the facelift ('phase 2') or the power upgrade ('phase2.5') (as an option). mine's a 170bhp 'phase 2.5' one. it's got dsc and as part of dsc you get the slippery diff. you could buy it on its own for about £100-150 or with dsc for c£250..
in the dry it's awesome even on runflats you can tell the difference. in the wet it's good too but i really noticed when we were coming out of winter and it was a bit damp and there was all that cr4p on the road that it torquesteered.. but not too bad.
GPs have it as std otherwise it's an option (althought the later line built JCWs may have had it chucked in for free..? not sure about this).
Edited by baSkey on Friday 8th June 12:46
So it is a Torsen style diff.
AIUI, none of the torque sensing/biasing diffs can lock 100%. What they do do is transfer a percentage of the torque that the lower traction wheel can support to the wheel with greater traction. So if the engine's shunting 100lb/ft of torque down to the CWP, and one wheel only has enough grip to support 50lb/ft, then an open diff would allow that wheel to spin until the DSC/TC/right-foot reduced the engine's torque output to 50lb/ft (inertia notwithstanding). The ATB would divert a percentage (typically 25-28%) of the 50lb/ft to the other wheel which would then help to drive the car forward. This happens seamlessly before the low traction wheel has had a chance to spin.
So, in the RST's case, the torque steer is probably more to do with too high a transfer percentage, allowing the torque to shunt from side to side rather than the diff locking solid. Or it might actually be a suspension geometry shortfall.
All the above may be b
cks, as my brain goes into meltdown whenever I try to work out how an ATB diff works; all I know is now my Westfield donuts sublimely 
Paul
AIUI, none of the torque sensing/biasing diffs can lock 100%. What they do do is transfer a percentage of the torque that the lower traction wheel can support to the wheel with greater traction. So if the engine's shunting 100lb/ft of torque down to the CWP, and one wheel only has enough grip to support 50lb/ft, then an open diff would allow that wheel to spin until the DSC/TC/right-foot reduced the engine's torque output to 50lb/ft (inertia notwithstanding). The ATB would divert a percentage (typically 25-28%) of the 50lb/ft to the other wheel which would then help to drive the car forward. This happens seamlessly before the low traction wheel has had a chance to spin.
So, in the RST's case, the torque steer is probably more to do with too high a transfer percentage, allowing the torque to shunt from side to side rather than the diff locking solid. Or it might actually be a suspension geometry shortfall.
All the above may be b
cks, as my brain goes into meltdown whenever I try to work out how an ATB diff works; all I know is now my Westfield donuts sublimely Paul
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