Limited slip differential

strongdeo · 12-08-2008, 01:43 PM

The M3 lsd allows 100% of the torque to be sent to one wheel, what in practise does this mean and does it make it "better" than the Quaiffe version which sends 80% of the torque to one wjeel?

Serjames · 12-08-2008, 02:16 PM

Think you might have this slightly around the wrong way... Quaife is an 80:20 bias which mean that it only ever locks both wheels up to a MAXIMUM of 80% This is in effect how it works, it transfers torque to where it can actually work.

I.e. if one wheel is spinning, then it will, by the nature of the worm gears inside transfer the torque to the wheel which is Not spinning. It does this with a bias of 80%

Also why when it's under FULL LOAD the car will shimmy slightly as the torque is spread to where it can best work... Feels pretty cool, and you know that without the quaife it would have lost it ages ago...

M3 works in a different way, it simply locks both drive shafts under load and therefore gives 100% to both wheels all the time. In my understanding this COULD be a disadvantage as when it starts to let go there is no load balancing across the points of traction.. ie. It keeps BOTH wheels spinning the same, whereas the quaife will shift the power (shimmy)

Lol I don't think theres an answer to this really.

I know for a fact that Kevin Bird at Birds has changed quite a few e92 M3 Diffs for the Quaife unit... perhaps it was personal preference of the drivers, I dunno.

Not sure an M3 diff will ever fit in anything other than an M3 without LOTS of very costly engineering, so to a certain extend it's a moot point

SJ

strongdeo · 12-08-2008, 02:57 PM

Cool, thanksw for that, still not sure I understand the difference between 80% and 100%, although I think I do.

I had a test drive in the X^ which has the DPC which some people reckon will work it's way across the range in the course of time, certainly to the higher part of the range cars. The DPC works with xDrive so I suppose at this time it is configured towards 4wd but I wonder how that works in comparison to Quaiffe and M3 slip diff?

12-08-2008, 01:43 PM	#1
strongdeo Private 21 Rep 85 Posts Drives: F30 330d MSPORT Join Date: Nov 2008 Location: Birmingham, UK iTrader: (0)	Limited slip differential - M3 version compared to Quaiffe The M3 lsd allows 100% of the torque to be sent to one wheel, what in practise does this mean and does it make it "better" than the Quaiffe version which sends 80% of the torque to one wjeel?
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12-08-2008, 02:16 PM	#2
Serjames Colonel 128 Rep 2,426 Posts Drives: E93 335i M-sport Join Date: May 2007 Location: Surrey - UK iTrader: (0) Garage List 2007 E93 335i M Spo ... [0.00] 2003 Nissan Primera S [0.00]	Think you might have this slightly around the wrong way... Quaife is an 80:20 bias which mean that it only ever locks both wheels up to a MAXIMUM of 80% This is in effect how it works, it transfers torque to where it can actually work. I.e. if one wheel is spinning, then it will, by the nature of the worm gears inside transfer the torque to the wheel which is Not spinning. It does this with a bias of 80% Also why when it's under FULL LOAD the car will shimmy slightly as the torque is spread to where it can best work... Feels pretty cool, and you know that without the quaife it would have lost it ages ago... M3 works in a different way, it simply locks both drive shafts under load and therefore gives 100% to both wheels all the time. In my understanding this COULD be a disadvantage as when it starts to let go there is no load balancing across the points of traction.. ie. It keeps BOTH wheels spinning the same, whereas the quaife will shift the power (shimmy) Lol I don't think theres an answer to this really. I know for a fact that Kevin Bird at Birds has changed quite a few e92 M3 Diffs for the Quaife unit... perhaps it was personal preference of the drivers, I dunno. Not sure an M3 diff will ever fit in anything other than an M3 without LOTS of very costly engineering, so to a certain extend it's a moot point SJ __________________
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12-08-2008, 02:57 PM	#3
strongdeo Private 21 Rep 85 Posts Drives: F30 330d MSPORT Join Date: Nov 2008 Location: Birmingham, UK iTrader: (0)	Cool, thanksw for that, still not sure I understand the difference between 80% and 100%, although I think I do. I had a test drive in the X^ which has the DPC which some people reckon will work it's way across the range in the course of time, certainly to the higher part of the range cars. The DPC works with xDrive so I suppose at this time it is configured towards 4wd but I wonder how that works in comparison to Quaiffe and M3 slip diff?
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