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