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