Press Release
Chassis and Suspension
The BMW Z4 Coup?????????????????? offers supreme driving pleasure to the extreme limit. Indeed, this two-seater sports car enters new dimensions in driving dynamics only a few production cars are able to reach in the first place. The unique agility provided in this way is attributable to the unusually good harmony of vehicle weight and engine output, torsional body stiffness and sophisticated chassis technology.
Driving the BMW Z4 Coup?????????????????? in sporting style means enjoying the full performance and thrust of the six-cylinder power unit translated into pure driving dynamics in virtually every situation.
Sophisticated, highly developed control systems ensure that the car never exceeds the limits to driving dynamics, maintaining a supreme standard of active safety without in any way curtailing the dynamic character of this outstanding two-seater by intervening prematurely.
The chassis and suspension of the BMW Z4 Coup?????????????????? forms an ideal partner for the powerful six-cylinder engine. In its fundamental features the suspension is based on the BMW 3 Series also quite exceptional in its class, although the springs and dampers as well as the suspension kinematics and elastokinematics have been modified and enhanced to an even higher standard of all-round agility and handling.
Well-balanced axle load distribution, a low centre of gravity, as well as rear-wheel drive relieving the steering completely of drive forces offer optimum conditions for harmonious driving behaviour, very good traction and driving stability, as well as unusually high speeds in bends.
The very wide overall track of the car compared with the dimensions of the body, as well as the use of firm anti-roll bars on both axles, contributes directly to the car??????????????????????????????????????s driving stability, offering benefits very noticeable to the driver. The result is a driving experience of the highest calibre, with all the agility and dynamics of a thoroughbred sports car.
The spring strut front axle with forged aluminium track control arms, twin-sleeve gas-pressure dampers, rack-and-pinion steering, and anti-roll bars, ensures optimum road contact at all times. The central arm axle at the rear, complete with twin-sleeve gas-pressure dampers and an anti-roll bar, in turn, provides an optimum link between the rear axle subframe and the body of the car. This, in turn, sets the standard for very safe handling and avoids any kind of unwanted steering effects.
To enjoy an even more sporting style of motoring and performance, the genuine enthusiast can also opt for sports suspension lowering the entire car by 15 millimetres or almost 0.6????????????????????????????????????????.
Featured as standard, the runflat tyres have been developed especially for the Z4 Coup?????????????????? with its dynamic and sporting character.
DSC offering safe driving pleasure all the way to the limit.
The suspension control systems featured on the car again follow BMW??????????????????????????????????????s philosophy, not serving as additional suspension assistance, but rather enhancing driving pleasure to an even higher standard or, alternatively, helping to master critical driving situations when going to the limit. Anything else would be simply superfluous, since the suspension already has very substantial safety reserves to begin with.
The BMW Z4 Coup?????????????????? features the latest generation of DSC Dynamic Stability Control. This control system developed especially for BMW??????????????????????????????????????s sporting models was originally conceived to enhance driving safety on slippery surfaces by applying the brakes specifically on individual wheels ??????????????????????????????????????? for example in an abrupt manoeuvre or with the car starting to become unstable in a bend. Today DSC offers a far wider range of functions in terms of sporting performance, safety, and comfort. As an example, ASC Automatic Stability Control masterminds wheel slip by reducing engine power when required, applying the brakes selectively on a drive wheel threatening to spin, and thus re-stabilising the car. CBC Cornering Brake Control, in turn, incorporates asymmetric brake pressure regulation reducing possible oversteer of the car when applying the brakes slightly in a bend.
Higher traction for extra momentum.
DTC Dynamic Traction Control also integrated in the DSC stability system enables the driver to improve traction and, accordingly, drive power at the touch of a button on surfaces with greater driving resistance such as deep snow. A further advantage of DTC is that the driver is able to set the driving behaviour of the BMW Z4 Coup?????????????????? to even higher dynamic standards, capitalising even more than usual on the car??????????????????????????????????????s sporting character. As an example, DTC allows an increase in slip on the rear wheels, with traction being priorised at low to medium road speeds and then gradually reduced as the car starts to travel faster. Further criteria are also taken into account to adjust the higher slip thresholds to current driving conditions. This allows the motorist to drive the BMW Z4 Coup?????????????????? in almost the same agile style as with a limited-slip differential, without impairing the safety function of DSC when reaching extreme limits.
Additional functions making DSC even more efficient.
DSC offers a whole range of additional useful functions: DBC Dynamic Brake Control, for example, maximises brake pressure when the driver applies the brakes in an emergency. The Set-Off Assistant briefly applies the brakes when setting off on a gradient, to prevent the car from rolling back. Fading Compensation serves to automatically enhance road safety by minimising any fading of the brakes, while Brake Standby automatically pre-loads the brake pads for immediate brake action. Automatic Dry Braking of the brake discs, finally, improves brake response when driving in the wet.
Electric Power Steering for optimum steering qualities.
Electromechanical power steering enhances the dynamic and agile set-up of the suspension. The main component on this electric steering unit is an electric motor on the steering column operating in conjunction with a worm gear to enhance steering assistance. Steering forces are transmitted by an interim shaft in the steering to a mechanical steering transmission adjusting the position of the steering and the steering lock by way of thrust bars.
With the steering being set by means of sophisticated software, EPS allows a very high level of flexibility in choosing the optimum steering characteristics, provides an optimum compromise between the damping effect on the steering and feedback from the road, and minimises operating forces at low speeds and when manoeuvring. A further point is the optimum return motion of the steering wheel to its centre position after a bend. And in the DDC sports mode, finally, steering power assistance is reduced for an even more dynamic and more sporting feeling on the road.
Benefiting from EPS Electric Power Steering, the driver enjoys an even higher standard of steering comfort and superior steering precision on bad roads, with bumps on the road or imbalanced wheels not coming through all the way to the steering wheel. The last but equally important point is that EPS helps to save fuel, since it does not require any energy as long as the driver does not move the steering while the car is driving straight ahead. Compared with conventional power steering, this means a reduction in fuel consumption of up to one litre on 400 kilometres or 250 miles.
Brakes with optimum performance.
The brake system in the BMW Z4 Coup?????????????????? is optimised for minimum weight in order to give the car even greater agility. Further benefits are extreme stopping power, good resistance to fading, and a long service life. Measuring 325 x 25 millimetres (12.80 x 0.98????????????????????????????????????????) up front and 294 x 19 millimetres (11.57 x 0.75????????????????????????????????????????) at the rear, the brake discs are inner-vented for optimum cooling.
Runflat tyres with failsafe qualities.
The BMW Z4 Coup?????????????????? comes as standard on puncture-proof runflat tyres. Reinforced side flanks with additional inserts and temperature-resistant rubber compounds prevent the tyre from being compressed when empty or jumping off the rim. Even a sudden, complete loss of pressure does not endanger the driver ??????????????????????????????????????? also because all control systems remain fully functional. This allows the driver to proceed to the nearest service station without having to stop at a dangerous point. And doing without a spare or emergency wheel as well as a car jack, the weight of the car is reduced by more than 20 kilos or 44 lb, again in the interest of enhanced agility and dynamics.
Warning in the event of a pressure loss.
In the event of a gradual loss of pressure accounting in statistical terms for approximately 80 per cent of all tyre problems, the electronic TPC Tyre Pressure Control system warns the driver via a display in the instrument panel. The system responds shortly after setting off or from a road speed of 15 km/h, such an early warning enabling the driver to rectify tyre pressure in good time.
Runflat tyres drive and behave in the same way as conventional tyres.
The wheel rims used are fully compatible, meaning that if necessary a ???????????????????????????????????normal???????????????????????????????? tyre may also be fitted on a runflat rim. And as a further advantage runflat technology is available both on summer and winter tyres.
