| Saab, the Swedish automaker, has | | | | being activated as the clutch plates are |
| developed the XWD "Cross Wheel Drive" | | | | forced together under hydraulic |
| system, with intention to optimize | | | | pressure. In effect, the RDM becomes |
| vehicle handling and stability in all | | | | engaged. In such process, detection of |
| driving conditions. Currently, the | | | | wheel slip before the TTD activates is |
| system is being offered as an option in | | | | required, making it a significant |
| the 2008 Saab Turbo X and Aero versions | | | | improvement in the technology. |
| of the 9-3 Sport Sedan and SportCombi. | | | | In open road cornering, Saab XWD offers |
| It is being partnered with a 280 hp (206 | | | | enhanced and more finely balanced |
| kW), 2.8 V6 turbo engine that produces | | | | chassis dynamics. The data from the |
| almost 15 percent more maximum torque of | | | | vehicle's ABS/ESP sensors are being |
| 400 Nm/295 lbs.-ft.), to enhance the | | | | utilized. And, the programming of the |
| available traction. | | | | system permits the application of rear |
| The all-wheel drive system will be | | | | drive in balancing both oversteer and |
| available with either a six-speed manual | | | | understeer characteristics to optimize |
| or six-speed automatic transmission. It | | | | stability and roadholding. |
| will provide to impressive features, | | | | For highway cruising, there is only |
| namely: pre-emptive engagement of the | | | | about 5 to 10 percent of the engine |
| rear wheels to optimize traction at | | | | torque is basically used in the rear |
| take-off; and an active rear | | | | wheels to provide a measure of greater |
| limited-slip differential (eLSD) to | | | | stability and enhancement of fuel |
| allow variable torque transfer between | | | | consumption. |
| the rear wheels. | | | | The eLSD holds the most significant role |
| The Cross Wheel Drive is a fully | | | | in Saab XWD. It is the first application |
| automatic on-demand system. It could | | | | of an electronically-controlled, rear |
| send up to 100 percent of engine torque | | | | limited slip differential in the |
| towards the front or rear wheels when | | | | segment. Along with RDM, the eLSD |
| necessary. Its sophisticated operation | | | | operates through pressurized clutch |
| adds further sporty dimension to the | | | | plates under a principle same as with |
| driving experience with the new Saab | | | | the larger TTD. |
| Turbo X and 9-3 Aero XWD. It produces | | | | The eLSD also provides the driver better |
| fine balancing of the drive torque | | | | control on hard cornering and high speed |
| between the front and rear axles that | | | | maneuver. It happens through the |
| raises the threshold where ESP throttle | | | | application of either more or less |
| and braking interventions are triggered; | | | | torque to the wheels, helping the rear |
| thus, provides more scope for intimate | | | | follow the direction of the front |
| driver involvement. | | | | wheels. Without requiring 'outside' |
| The state-of-the art all-wheel drive | | | | intervention from electronic stability |
| system is being dominated by its own | | | | aides and quality Saab struts, the |
| electronic control unit that works with | | | | vehicle can be kept balanced and be |
| the engine, transmission and ABS/ESP | | | | tightly controlled. |
| control modules. In the front | | | | Fitment of a new rear sub-frame, in the |
| final-drive, the hardware comes with a | | | | process of installing the Saab XWD, is |
| Power Take-off Unit (PTU), which | | | | required to carry the RDM, revised rear |
| transmits engine torque through a | | | | suspension geometry and new wheel hubs |
| prop-shaft in the Rear Drive Module | | | | for the drive shafts. Wheelbase and rear |
| (RDM). It works with wet, multi-plate | | | | track dimensions are kept unaltered. |
| clutch units from Haldex, namely a | | | | Currently, Saab, as a division of |
| Torque Transfer Device (TTD) and an | | | | General Motors Corp. Saab Automobile |
| electronically-controlled Limited Slip | | | | USA, is providing premium automobiles |
| Differential (eLSD). | | | | for Saab Automobile AB, Sweden. |
| In the process of take-off, the TTD is | | | | |