[adz2k11]

i have a quaife diff from birds auto in uk fitted to my vehicle

now its a good upgrade but i was always under the impression that this acted just like a normal lsd as is present in a m3

however, when i get the car up on the ramps and hold one wheel while spinning the other it doesnt click and lets me spin both which indicates the absence of a slipper..

ive read up more on this and apparently the quaife is a torque biasing mechanism so it doesn't work like a slipper..

im still abit confused though, can someone explain the benefits on the road between the two?

thanks

adz

[jdbretz]

As I understand it, the Quaife is an ATB (Automatic Torque Biasing) diff, and the M3 diff is clutch based diff. Under zero load (one tire completely in the air) the Quaife will not send any power to other wheel, where as in the M3 diff will transfer the load to the wheel with more traction under this circumstance. Most people argue that the zero load condition is very rare and short lived even when it does occur, so its not really a big deal. As far as the benefit of one or the other, someone with a better knowledge of how they work will have to answer that.

[adz2k11]

Originally Posted by jdbretz

As I understand it, the Quaife is an ATB (Automatic Torque Biasing) diff, and the M3 diff is clutch based diff. Under zero load (one tire completely in the air) the Quaife will not send any power to other wheel, where as in the M3 diff will transfer the load to the wheel with more traction under this circumstance. Most people argue that the zero load condition is very rare and short lived even when it does occur, so its not really a big deal. As far as the benefit of one or the other, someone with a better knowledge of how they work will have to answer that.

good description mate, that makes sense, so essentially its only on zero load that there is a difference? on the road they should performance similar?

[jdbretz]

Originally Posted by adz2k11

good description mate, that makes sense, so essentially its only on zero load that there is a difference? on the road they should performance similar?

Correct. Based off my limited knowledge on the differences and what I have read, I would say yes they would perform very similarly on the road with the slight advantage going to the clutch type LSD's especially under extremely hard cornering. Another difference is the Quaife requires no maintenance, where as the clutch type may eventually require some maintenance if the clutches wear out (however I had an old 89' 325i with a stock LSD (back when all BMW's came with one) and put 270,000 miles on it and never had a issue out of the LSD).

[achien]

with the bumps and potholes on the road, the zero load situation happens more often than not. however, the M3 clutch type differential is costing 2x as much as the torsen type (Quaife). whether the "extra" performance is worth 2x will be each person's call.

in the end, you do get what you pay for.

Originally Posted by jdbretz

As I understand it, the Quaife is an ATB (Automatic Torque Biasing) diff, and the M3 diff is clutch based diff. Under zero load (one tire completely in the air) the Quaife will not send any power to other wheel, where as in the M3 diff will transfer the load to the wheel with more traction under this circumstance. Most people argue that the zero load condition is very rare and short lived even when it does occur, so its not really a big deal. As far as the benefit of one or the other, someone with a better knowledge of how they work will have to answer that.

Originally Posted by adz2k11

good description mate, that makes sense, so essentially its only on zero load that there is a difference? on the road they should performance similar?

[Rotary Rasp]

If I recall correctly, the clutch type soak up more horsepower.