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New Vauxhall Insignia Details - (UK) - Chassis
July 23rd, 2008
- Advanced chassis for more comfort and control
- New generation FlexRide allows personalised settings
- Class-leading, Adaptive 4X4 provides optimal traction
An all-new chassis underpins the Vauxhall Insignia. Its MacPherson strut front suspension has dual path top mountings in the body structure turrets, separating the transfer of spring and damper loadings. To reduce unsprung weight, the combined steering knuckle and strut carrier is made from aluminum, and the anti-roll bar from hollow section steel.
Steering and lower suspension arms are attached through two mountings to a substantial front sub-frame, which is bolted via four bushings to the front structure’s longitudinal members. This isolated mounting technique helps reduce the transfer of road shocks and noise to the cabin. The hydraulic damping of the rear arm mounting also adds to ride comfort.
The rear suspension comprises an independent, four-link layout, with the second lower link in aluminum. For all-wheel-drive applications, a lower H-arm is used. The bushes in the rear-most arms are hydraulically damped to help prevent road shocks and vibrations from being transmitted through the steering wheel.
The new FlexRide system enables drivers to choose a chassis setup that matches their own particular driving style. In all modes, the chassis management system automatically adapts damping in real time to the driving and road conditions.
In Sport mode, FlexRide not only provides stiffer damping, but also swifter throttle response. It also changes the valving in the Variable Effort Steering (VES), raises the shift-points of the automatic transmission to a higher rpm and adjusts the Adaptive 4X4 system for more rear-wheel drive. In Sport mode, the AFL system reacts more quickly, and the lighting on the instrument panel changes from white to red to add to the driving experience.
In the customisation menu, accessible via the infotainment display (optional on SRi models), the driver can personalise the Sport mode by specifying which functions are activated when the Sport button is pushed. For instance, the electronically controlled dampers, VES, and all-wheel drive can be added or switched off.
At the heart of FlexRide is the Driving Mode Control (DMC) which oversees and executes the system’s settings, allowing the car to react to sudden changes in driving style or emergency situations. For example, if an obstacle must be avoided when the car is in ‘Tour’ mode, various chassis sensors convey this to the DMC and the dampers are adjusted within a split second, optimising acceleration, braking and cornering.
FlexRide is standard on all petrol models, other than the 1.8 ECOTEC, where it is available as an option on SRi models. All 130PS 2.0CDTi SRi models can be specified with FlexRide as an option, while SE, Elite and SRi models powered by the 160PS 2.0CDTi also receive FlexRide as an option.
Both the Insignia’s turbocharged petrol engines are available with the latest-generation advanced all-wheel-drive system. This system will also be available on future, more powerful diesel versions. Called Adaptive 4X4, it is designed to optimise handling and driving stability in all conditions, as well as increase traction at take-off and on slippery surfaces. Under electronic control, the Haldex hydraulic rear clutch unit continuously adjusts and optimises torque distribution between the front and rear axles.
The Adaptive 4X4 control unit is fully integrated with Insignia’s other control systems. It consists of a Power Take-off Unit (PTU) in the front final-drive that transmits engine torque through a prop-shaft to the Rear Drive Module (RDM), which includes a Torque Transfer Device (TTD). A rear electronic Limited Slip Differential (eLSD) enhances the system on SRi models.
Adaptive 4X4 processes signals from the ESP sensors, the steering angle sensor and accelerator pedal position to adapt power distribution to the prevailing driving conditions. While offering better traction on low friction surfaces, the sophisticated operation of the Adaptive 4X4 improves stability in all situations.
In the SRi variant, Adaptive 4X4 is coupled to an electronically-controlled eLSD, which takes chassis control a step further. It is installed alongside the RDM and operates via pressurized clutch plates on a principle similar to the larger TTD. In icy or wet split-friction conditions, for example, it uses input from the rear wheel speed sensors and can transfer up to 50% of torque between the drive shafts, to whichever wheel has more grip.
The eLSD also gives the driver enhanced control when cornering hard or completing a high speed manoeuvre, such as a lane change, by momentarily applying more or less torque to either of the wheels to help the rear of the car follow the direction of the front wheels. That way, the eLSD keeps the Insignia better balanced and more tightly controlled without requiring ‘outside’ intervention from ESP.