Moreover, with a lighter engine (17% less than GS 430's 4.3 litre V8 unit) and the mounting of the hybrid powertrain's heavier masses closer to the centre of gravity, the vehicle's moment of inertia is also improved over that of the GS 430, which means more agility. In addition, the GS 450h is equipped with a limited-slip differential which, allied to the location of the hybrid battery directly over the rear axle, further improves rear wheel traction.


VARIABLE GEAR RATIO STEERING (VGRS)

The GS 450h is equipped with an Electric Power Steering (EPS) system featuring Variable Gear Ratio Steering (VGRS).

VGRS employs an actuator attached to the intermediate steering column shaft, which alters the steering gear ratio according to vehicle speed. The gear ratio is seamlessly and continuously adjusted between 12.4:1 and 17.2:1 - a difference of some 39% - whilst the number of turns, lock-to-lock simultaneously varies between 2.7 and 3.7.

At very low speeds, the gear ratio is at its lowest to reduce both the steering input and effort required during tight cornering and parking manoeuvres. At medium speeds, the gear ratio is optimised for accurate vehicle response when cornering. And at high speed the ratio is at its highest to ensure gentle response to inputs and maximum vehicle stability.

In addition, VGRS also cooperates with VDIM to assist the driver in extracting the most out of the GS 450h's dynamic envelope.



SUSPENSION

The new Lexus GS 450h is equipped with a double wishbone front and multilink rear suspension system which combines ride comfort with the excellent handling and dynamic abilities appropriate to a luxury sports sedan.

Front suspension
The front, high-mount, double wishbone suspension system combines lightweight, forged aluminium knuckles with high tensile steel arms and a hollow anti-roll bar to reduce unsprung weight.

In addition, new, forward mounted power steering gear allied to low toe variation along the suspension stroke promote a more linear yaw response, precise steering control and excellent straight line, high speed stability.

Rear suspension
To the rear, an advanced multilink set-up with toe control arms and an aluminium rear axle carrier combines stiffer suspension component materials with a reduction in unsprung mass for excellent ride comfort with high cornering stability. The adoption of a double-linked upper arm and integrated bearings and hub combines optimised geometry and high rigidity with significant weight reduction.

The utilisation of a multilink configuration facilitates the optimum balance of handling, stability and ride comfort: The upper arms contribute to a reduction in upward spring motion, the mid-arm contributes to reduced body roll, and the lower arm provides an improved anti-lift / anti-squat ratio.


Adaptive Variable Suspension (AVS) with Non-linear H
Control Logic

The Adaptive Variable Suspension (AVS) system allows the driver to select the GS 450h's ride characteristics with a choice of two damper settings activated via a switch adjacent to the gear lever; "Normal" mode, for everyday driving comfort, and "Sport" mode, for improved body control and precise responses to steering input whilst cornering.

Selecting the AVS system's "Sport" mode automatically increases the difference between inner and outer shock absorber damping force through corners to further reduce body roll. Simultaneously, the Variable Gear Ratio Steering (VGRS) automatically reduces the steering gear ratio whilst the Electric Power Steering (EPS) increases steering assist torque to compensate for the increase in steering effort. These measures combine to minimise body roll, sharpen vehicle handling and optimise steering feel for the ultimate in sports sedan driving.

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