Geared torque-sensitive differential
Audi Quattro Torsen Diff
Geared, torque-sensitive mechanical limited slip differentials utilize worm gears to "sense" torque on one shaft. The most famous versions are:
* Torsen differential invented by Vernon Gleasman in 1958, then sold to Gleason Corporation, who started marketing it in 1982;
* Quaife differential, sold under the name Automatic Torque Biasing Differential (ATB), covered by European Patent No. 130806A2.
* Eaton Corporation differential, sold under the name Eaton Detroit Truetrac.
Geared LSDs are less prone to wear than the clutch type, but both output shafts have to be loaded to keep the proper torque distribution characteristics. Once an output shaft becomes free (e.g., one driven wheel lifts off the ground; or a summer tire comes over ice while another is on dry tarmac when the car goes uphill), no torque is transmitted to the second shaft and the torque-sensitive differential behaves like an open differential.
Geared LSDs are dependent on the torque and not on the speed difference between the output shafts. Such differentials may not be adequate on extremely slippery surfaces such as ice (or thin air, when a drive wheel loses ground contact altogether).[3]
Geared LSDs may be used:
* to reduce torque steer in front-wheel drive vehicles;
* as a center differential in four-wheel drive (e.g., on the Audi Quattro);
* in rear-wheel drive vehicles, to maximize traction and make oversteer easier to manage (as in drifting). Although, for extreme drifting, a geared LSD is less effective compared to a clutch type LSD.
i found this here:
http://en.wikipedia.org/wiki/Limited_slip_differential but i don't understand the bolded part....could anyone explain why this would happen to Quaife LSD if this is what most people say about it:
the QUAIFE Differential powers both drive wheels under nearly all conditions, instead of just one.
With an ordinary open differential, standard on most cars, a lot of precious power is wasted during wheel spin under acceleration. This happens because the open differential shifts power to the wheel with less grip, along the path of least resistance.
The QUAIFE, however, does just the opposite. It senses which wheel has better grip, and biases the power to that wheel. It does this smoothly and constantly, and without ever completely removing power from the other wheel. In cornering, while accelerating out of a turn, the QUAIFE biases greater power to the outside wheel, reducing inside-wheel spin. This allows the driver to begin accelerating earlier, exiting the corner at a higher speed