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1987 UK Citroën CX Brochure  Return to CX Index page

FRONT WHEEL DRIVE WITHOUT COMPROMISE. A PRODUCT OF EXPERIENCE.

One way round the problem of engine size in front wheel drive, is longitudinal location of the engine block. But this may put some of the engine’s mass ahead of the front axle. Adding rigidity where it’s undesirable in a collision- and the weight where (multiplied by leverage) it could create serious handling problems. This becomes more serious with diesel engines, which are heavier than their petrol equivalents.
By contrast, the CX enjoys access to a wide range of compact petrol and diesel units which can be transversly mounted, driving the front wheels.
The CX's suspension and steering geometry and unique Varipower steering neutralise the other objection to front wheel drive in large cars - torque steer, where excessive power via the front wheels pulls the car off course.
This kind of planned engineering is the clearest evidence of Citroën's fifty years experience in the application of front wheel drive, aerodynamics and safety-conscious design.

AERODYNAMICS AND SELF-LEVELLING SUSPENSION, ANOTHER PART OF THE STORY

Paradoxically, the CX's aerodynamic performance is dramatically enhanced by its suspension system.
On the face of it, it seems obvious that a car with a low drag co-efficient will be consistently efficient.
But aerodynamics isn't just a matter of styling and wind tunnel tests. On the road with occupants and luggage, a car is subject to very different forces. Load a conventionally sprung car with rear passengers and luggage and the body's angle to the road - and hence its aerodynamic profile change significantly.
Not so the Citroën  CX. Its self levelling hydropneumatic suspension maintains the same ride height and body angle whatever the load or how the load is distributed.
So the CX's drag coefficient, as measured in the wind tunnel, is maintained in practice. A factor far more significant than minor differences in theoretical drag figures between one type of car and another,
The self-levelling system affects the performance of the CX in other ways.

HYDROPNEUMATIC (HYDRO-FLUID PNEU-AIR/GAS): A SIMPLIFIED EXPLANATION.

Just as most cars sag as they're loaded, so their handling is affected. Equally, an unladen van or estate can have a hard ride and jittery handling.
The CX's suspension system eliminates these problems because the conventional car's metal springing is replaced by gas spheres.
A metal spring becomes progressively more compliant as the load upon it increases. However the gas spring becomes progressively LESS compliant as it is loaded.

In the CX, the gas spheres are connected to cylinders at each wheel which are part of a powered hydraulic circuit. As the car is loaded, the gas in the spheres is compressed, but a pump  and  reservoir of hydraulic pressure compensates for any vertical displacement of the wheel restoring normal ride height and angle of the CX to the road.
This permits the CX to be quite softly (and thus comfortably) sprung, yet its ride height and  handling remain consistent whether you drive alone or with maximum payload.

SELF LEVELLING AND SAFETY

The CX's suspension geometry gives the CX anti-dive braking and anti-lift acceleration - the last being significant because it can affect steering control and grip.

A LANDMARK IN CAR DESIGN.

The suspension's hydraulics are part of a larger system which also powers the brakes and steering.
This gives the CX immense braking force, available instantly to take vital milliseconds off the total time the driver takes to respond. Full power is available from the moment the engine starts. It is independent of engine pressure or revs and with the engine stopped the brakes and power steering are backed by the pressure reservoir. The connection between suspension and braking is used to limit maximum rear brake pressure proportional to rear payload - to help prevent the rear wheels locking under clearance to avoid obstacles on rough terrain or lower the body of the car to facilitate loading or tow-hook hitching.

POWER STEERING THAT THINKS.

Conventional power steering can become disconcertingly light at speed.
Though  modern  systems  usually compensate in some way for road speed few approach the accuracy and feel of the CX's Varipower system.  This uses rack and pinion - more precise than recirculating-ball, used in some cars. And an automatic self centering device with a speed sensor to control the amount of effort required to turn the wheel away from the straight ahead position. Conventional systems merely reduce assistance at speed. Thus, the CX's steering is quick and almost effortless in tight traffic but, at speed, can feel more secure than unpowered steering.  And this feeling is quite justified - the CX's steering and suspension geometry is designed to eliminate directional  instability  caused  by variations in road surface.  Some rear suspension systems subject the car to a slight steering effect at the extremes of their vertical travel, known as bump steer. The CX's true trailing  arm  rear  suspension  and equal-length arm  front suspension preclude this effect and the car remains on course with minimum corrections.