What Is It?
The Tran-X powered by Quaife LSD is a multi-plate limited slip differential. The range is popular within grassroots motorsport, in particular rally, autocross and autotest disciplines. Unlike the Quaife ATB LSD, the Tran-X LSD locks if a driven wheel leaves the ground, maintaining drive at all times. With over 30 different settings for much of the range, the differential’s characteristics can be chosen to best suit the discipline. The properties of a plate-type differential mean the results are clearly mechanical in operation, and this does mean that the internal clutch plates do wear and will need maintenance and care to ensure peak performance throughout the racing season.
How It Works…
The Tran-X limited slip differential centre pack design incorporates two ramp blocks sandwiching two planet carrier pins, which are located in the radius between the differential’s leading and trailing ramp angle. As torque is applied to the Tran-X differential’s input, the pins ride up their respective leading ramps, pushing the blocks apart and increasing the transfer of torque across the axle, maximising drive and traction.
The angle of this ramp determines how quickly this torque transfer occurs within the Tran-X limited slip differential unit. A ramp angle of 35 degrees allows the blocks to be pushed apart more readily that a 55 degree setting, resulting in a more aggressive differential locking action.
In addition, the differential pre-load setting within the Tran-X LSD defines the level of contact friction between the clutch plates themselves. The higher the pre-load, the more rapidly that friction increases between the plates, also creating a more aggressive differential action. Combined with the choice of ramp angles, this enables fine adjustment of the Tran-X limited slip differential’s torque transfer characteristics, allowing users to alter the dynamic handling balance of their car.
Typical Tran-X limited slip differential settings for a lightweight track car would be 45/90, allowing progressive application of power for optimum acceleration. Some Tran-X limited slip differentials feature dual ramp blocks, allowing ramp angles to be changed between two combinations, for example track and fast road settings (disassembly and reassembly of the Tran-X LSD unit is required.) Tran-X differentials with a less aggressive ‘super-lightweight’ plate setting (with a pre-load of 10-15 lb.ft) are also available for certain road and kit car applications to optimise performance and reduce operating noise.
We also offer a 4-pin ‘trials spec’ (non LSD) differential for use where strength is vital, but all forms of LSD are banned by the rules of a particular discipline.
Unlike the Quaife automatic torque biasing (ATB) differential, the Tran-X LSD design uses internals with a finite service life. As such the Tran-X LSD will require regular maintenance as a function of the pre-load settings, intensity and duration of use.