A modern classic - this status was acquired by the Audi Cabriolet in the nine years or so that it was in production. Now its long-awaited successor is finally about to make its appearance and it, too, has all the makings of a cult object: the new A4 Cabriolet combines dynamism and exclusiveness, state-of-the-art technology and an equipment specification that leaves nothing to be desired. A genuine Audi.
The new model, which is 4.57 metres long and 1.77 metres wide, incorporates the classically elegant characteristics of the Audi Cabriolet in a new design, at the same time underlining the sporty image of the Audi brand.
The new Audi A4 Cabriolet has an electro-hydraulically operated hood with a heated glass rear window as standard equipment. Outstanding acoustic insulation and excellent suitability for winter conditions are attributes that can be taken for granted on an Audi Cabriolet hood.
The uncompromising power flow of the engines, developing up to 162 kW (220 bhp), and the aluminium suspension, coupled with typical Audi simple but elegant design and exclusive equipment, will also characterise the A4 Cabriolet - the perfect basis for a new kind of driving experience. There’s no doubt that the new Cabriolet is the emotional spearhead of the sporty A4 model family.
A success story: the tradition of the Audi Cabriolet
Convertibles, or cabriolets as they are also known, enjoy a long tradition at Audi: the very first DKW, for example, appeared as a cabriolet in 1928. The large Horch cabriolets were dream cars of their time, and the NSU Wankel Spider caused a sensation in the 1960s. This was a car that was noted not least for its sporting qualities: a Wankel Spider won the GT Rally World Championship in 1966.
The Audi Cabriolet - already a modern classic - continued this tradition after an interruption of 25 years. 72,000 customers worldwide - around 45,000 in Germany - opted for the Audi Cabriolet between the time it went into production in May 1991 and the end of production in July 2000.
The first version of this open-top four-seater was based on the Audi 80 and had a 2.3-litre five-cylinder engine developing 98 kW (133 bhp). The range was gradually extended to four engine versions throughout the model’s production life. A move which represented a new departure in this class was the launching of a 1.9 four-cylinder TDI version with an output of 66 kW (90 bhp).
This engine helped diesel technology break into the domain of open-top cars. In Germany alone, its market share was over 20 percent for quite a number of years. The top engine version of the outgoing model was a 2.8-litre V6 developing 128 kW (174 bhp).
The lasting success of the Audi Cabriolet is reflected in the rate at which it lured customers away from other brands: in 1998, its eighth year on the market, this four-seater convertible still managed to capture 59 percent of its customers from the competition.
Dynamic and exclusive: the design
The Audi A4 Cabriolet is a vehicle whose temperament and unique quality are immediately obvious at first glance: the flat front end, the subtle wedge shape and the powerfully contoured tail with visible tailpipes are clear indications of the sporting prowess that it has inherited from its designers.
With its powerful proportions and the unique, overtly dynamic shape of the front and tail ends, the new Cabriolet retains an extremely individual aura. The windscreen frame with its aluminium finish and the aluminium strips along the waistline additionally underline this distinctive design.
The distinct, round wheel arches and the basic line of the silhouette are reminiscent of the characteristic design features of the current A4 series. The Cabriolet’s design is also characterised by a scrupulously economical approach. No swage lines or edges interfere with the dominant flat, taut surfaces and expansive arches. The result is an unaccustomed harmony of opposites: tranquillity and forward urge, geometric precision and palpable emotion.
The double radiator grille with chrome surround and the flat headlights with three-tube design behind a clear-glass cover indicate that the Cabriolet is a member of the A4 model family, yet still have their very own aura.
The geometry of the joins is mapped out with exactitude, as if with a single stroke of the pen. Here, the body join has been elevated to the status of a deliberately placed structural feature on a large-surface sculpture, instead of a mere line of contact between two body sections. Vertical joins connect the car’s underbody with the headlights; the bumpers genuinely seem to be supporting the lighting units.
When open the hood is fully retracted and nothing interferes with the characteristic shoulder line which gives the vehicle body a smooth edge. But even with the hood closed, the dynamism and harmony of the silhouette are preserved. The wide arch of the roof’s outline, without any visible ridges created by the linkage, accentuates the body’s flat proportions and the subtle wedge shape of the unit as a whole.
The harmonious tail-end unit benefits from a new aerial system for radio, telephone and navigation system that is integrated into the luggage compartment lid, away from view.
The outstanding material quality and finish of the Cabriolet interior are typical of Audi. The interior design, perfectly matched to the styling of the exterior, plays a significant part in giving the entire Audi A4 Cabriolet an elegant overall appearance.
Its distinctly sporty driving area is carried by the striking centre console. Round air vents accentuate the overall dynamic character. In this way the interior of the Cabriolet is also kept deliberately distinct from that of the other A4 models, consequently demonstrating its exclusiveness.
The body: class benchmark for vibrational comfort
From the very outset, Audi’s body specialists sought to create a structure that would represent the optimum in terms of both static and dynamic rigidity, and would be as close as possible to the characteristic of the saloon. Potential that enhances both the car’s dynamic performance and its vibrational comfort. As far as combining these two qualities is concerned, the designers’ objective was therefore as follows: the Audi A4 Cabriolet should set nothing less than the class benchmark.
The rigidity of the A4 Cabriolet body provides the ideal basis for unspoilt driving pleasure. The best measure of this is the static torsional rigidity of the bodyshell: it is more than twice as rigid as its predecessor - a quantum leap.
Measures designed to increase strength and rigidity also affect the choice of material grades and joining techniques. For instance, high-strength and ultra-high-strength panels account for more than fifty percent of the bodyshell’s weight. Optimised wall thickness in conjunction with improved-quality weld points help to boost the structural durability of the body significantly.
The lower rigidity that is inevitable on a convertible compared with vehicles with a permanent roof could be compensated for on the Audi A4 Cabriolet above all by an optimised bodyshell structure. The body is in addition reinforced by a rigid bolted-on subframe at the front, with additional diagonal struts at the front and rear.
Rigid structures
Countless different measures - and plenty of detailed optimisations - were necessary to achieve the required result. Overall tuning therefore took place for the first time before the first body prototypes were built: the basis for the efficiency of the experimental vehicle tuning was created during computer simulation.
In this phase the focus was not only on the structure of the body itself, but also on interaction with suspension and assembly movements.
The result of these development processes can be felt: the A4 Cabriolet remains unshakeable on roads of all kinds. Passengers are not troubled unnecessarily by either high or low-frequency vibrations.
What is amazing is that even the distinctly sporty overall tuning of the suspension is fully in accord with a high level of ride comfort.
Even driving pleasure benefits from body rigidity because the direct steering enables the A4 Cabriolet to be guided extremely accurately around corners. This is made possible by the special steering column connection that takes account of the vibrational behaviour that is specific to convertibles. The steering bracket is additionally supported, the module cross member is connected to the windscreen cross member - measures that play a decisive role in reducing vibrations at the steering wheel to a minimum.
Crash rigidity: of saloon standard
The A-post of the Audi A4 Cabriolet - which plays a particularly vital part in a roll-over - is reinforced ultra-efficiently. High-strength reinforcing tubes and the generally optimised design of the posts assure the desired properties.
Sills with an optimised thickness and cross-section boost the occupant cell’s strength and optimise occupant protection. High-strength tubes are also used in the seat structure, as a means of enhancing occupant safety in the event of a lateral collision.
The doors, too, perform a very special safety function on this model; their mere dimensions highlight the differences compared with the smaller doors on the four-door A4 saloon and Avant models. In conjunction with the structural reinforcements in the sill and a cross reinforcement of the body beneath the rear seat bench, special impact members in the doors ensure the highest level of safety.
This guarantees that crash safety matches the exceptionally high standard set by the A4 saloon, even in a side pole impact.
At the car’s rear end, the double rear wall improves the rigidity of the body. Occupant protection benefits from the standard roll-over protection system that is subtly integrated into the double rear wall.
Comprehensive safety
The objective of Audi’s developers was to create a passive safety concept that is on a par with that of the A4 saloon. The latter model has already demonstrated in impressive style just how effective its safety system is in several crash tests, including the Euro NCAP test for which it was awarded four stars.
The comprehensive safety package contains seat belts with belt-force limiter and belt tensioner for all passengers, together with full-size front and side airbags. The side airbags integrated into the front seats are designed to protect the head and thorax.
An active roll-over protection system provides additional safety if the car overturns. In this case, two protective bars, controlled by sensors, are triggered behind the rear passengers within milliseconds. Together with the extremely rigid windscreen frame, they help to preserve survival space for all occupants if the car turns over.
The standard Electronic Stability Program ESP with hydraulic brake assist provides for maximum active safety.
More than mere weather protection: the hood
The Audi A4 Cabriolet has, as standard, an electro-hydraulically operated hood that opens fully automatically at the push of a button - a process that takes less than 30 seconds and is the ideal way to enjoy the sun and open-air driving.
At the same time the new Cabriolet offers maximum operating convenience: a simple press of the button is all it takes to open and close the soft top. The side windows are lowered and raised again automatically; it is not necessary on the A4 Cabriolet to release a locking bracket manually or to undo a tonneau cover.
When the hood is being opened, the lid of its stowage compartment behind the rear seats is raised, and the hood is folded away out of sight. The flap then folds down flush with the body so as not to interfere with the dynamic shoulder line of the A4 Cabriolet.
The hood compartment itself can be varied in height from the luggage compartment: the driver can raise or lower the compartment as required using a lever. This increases the size of the luggage compartment considerably when the hood is closed.
The lined Cabriolet hood is also perfectly equipped for winter-weather use: it has a heated, scratchproof glass window, and its triple-layer structure and accurate fit shield the interior effectively against both adverse weather conditions and exterior noise.
The hood’s linkage is barely visible when the hood is in the raised position; the tautness of the hood and the cushioning prevent any “tent ridge” effect. The shape of the roof as a harmonious component of the Cabriolet design is thus preserved at all speeds.
The hood is also completely smooth on the inside. Together with the high-quality appearance of the surface, this look underlines the luxurious overall impression conveyed by the interior ambience.
Aerodynamics: close to the wind
In the field of aerodynamics, absolute drag coefficient records long ago ceased to be the sole measure of all things. This is especially the case with convertibles which generally lag way behind saloon cars due to their lack of permanent roof. But all Audi vehicles are built according to the motto that optimised aerodynamics is one of the most important criteria for moderate fuel consumption and good economy.
With a drag coefficient of 0.30 (closed; open: 0.33), the new Audi A4 Cabriolet also complies with this requirement, improving on its predecessor by no less than 15 percent. And compared with the current competition in the four-seater convertible segment, the Audi has nothing to hide either: even with the top down, it achieves a better drag coefficient than its key competitors with the roof closed!
The significance of this is not just the impressively low value itself, but the way it was achieved. After all, the significantly more spacious interior on the latest generation model necessitates a much larger frontal area compared with its predecessor. And now that the standard equipment specification includes air conditioning, the new A4 Cabriolet requires much more cooling air, which likewise has an adverse effect on the drag coefficient. On paper this would actually add up to an increase in the drag coefficient.
So how can a deficit like this be turned into a genuine gain in aerodynamic perfection? The first area of concentration is known as “shape optimisation”; this begins in the early development phase with the help of computer-aided simulation and 1:4 wind tunnel models. Aerodynamics therefore accompanies the entire course of product development, from the first virtual and real models to prototypes and pre-production vehicles right up to the production launch.
The aerodynamic talents of the A4 Cabriolet are visible both at the front and at the rear of the vehicle. One result of the detail optimisation in the wind tunnel is the V-shape of the front end including the aerodynamic styling of the bumper and the front spoiler beneath it.
At the tail end, which differs from that of the saloon as clearly as the front end, it is the raised edge on the rear end of the luggage compartment lid that catches the eye: a detail that helps to reduce lift considerably without spoiling the streamlined silhouette of the Cabriolet in the least.
But that’s not all. One zone which is generally not visible to the driver offers immense potential for optimising the vehicle’s aerodynamics: the underbody. The target aerodynamic shape is seemingly very simple: a smooth underbody would represent the ideal.
Aerodynamic underbody
Faired underbodies have already proven just how effective they are, particularly in motor sport. However, considerable detailed work has to be carried out before they can be used on production vehicles. This calls for highly advanced wind tunnel technology.
The new Audi wind tunnel centre in Ingolstadt is specially designed for simulating on-road driving. Virtually no other wind tunnel is able to include in its analysis wheel rotation and the simulation of the road using moving belts under the vehicle. The aerodynamics engineers therefore succeeded in developing a largely smooth and low-resistance underbody which also satisfied practical requirements with regard to weight and ease of installation.
Putting on the pressure
The airflows to and from the radiator area, which are of considerable aerodynamic importance, can be analysed at the Audi wind tunnel centre. For instance, it was possible to move apertures for cooling air to zones where the aerodynamics create a positive pressure. Positive pressure also promotes the supply of fresh air for the air conditioning.
Conversely, the outlet apertures for the air extracted from the passenger compartment are located below the rear bumper on the A4 Cabriolet. This is because there is moderate negative pressure here. This careful choice of apertures results in a largely loss-free and therefore efficient cooling and air conditioning system.
All these measures taken in isolation appear to be no more than a drop in the ocean, but they all add up to an impressive overall drag coefficient for the new Cabriolet.
Calming the storm
Audi engineers also devoted considerable development time to the problem of wind noise. One example of many are the exterior mirrors, which have always caused aeroacoustics engineers in particular one of their biggest headaches.
The mirrors themselves do not produce an annoying noise. However, the wake behind the mirror housing must not strike the side window, for instance, as the front passengers would otherwise register a pronounced, high frequency airflow noise. This is a phenomenon that the new Audi A4 Cabriolet avoids thanks to its design. Even details such as a highly efficient mirror-gap seal are developed in the wind tunnel and consequently contribute to the car’s good overall aeroacoustic impression.
The work that has been carried out on the door seals is equally important. Like their counterparts on the A4 saloon, these were developed in Audi’s aeroacoustics wind tunnel. In the same way as the saloon, the Cabriolet therefore has two sealing lines in the lower door area (one line in the region of the window) that effectively block out outside noise. The new flat wipers also produce an exceedingly low wind noise level: this has already been proven in particularly impressive style in the A6 series.
The aeroacoustics of the hood were also optimised in the Audi wind tunnel in the course of a number of tests. An integrated insulating mat effectively absorbs sound. The surface and design of the closed soft top help to keep the wind noise level down. And, together with extensive sound-insulating measures in the body at the rear end, the glass rear window also reduces the wind noise level in the interior.
These are just a few of many measures which together make for impressive reading: compared with the predecessor, the sound-pressure level in the new A4 Cabriolet has been reduced by no less than five dB(A) or 45 percent. This adds up to a significant increase in comfort for the car’s occupants and a clear edge on the competition.
Things get a little louder in the A4 Cabriolet with the roof open - this is usual for a car of this kind and is also all part of the fun of driving a convertible. The occupants, however, will hardly notice any turbulence.
If the rear seats are not occupied, an optional wind deflector can be attached in next to no time: this keeps the interior draught-free, all the way up to motorway speeds.
Perfectly dimensioned for four people: the spacious interior
The occupants of the Cabriolet are treated to very high class travel, in terms of both safety and the available space inside the car. The wheelbase has been increased by 100 millimetres compared with the previous generation.
This means considerably more room in all directions; the A4 Cabriolet is a full-size four-seater vehicle. 66 millimetres more knee room for the rear passengers, 33 millimetres more shoulder room at the front and as much as 52 millimetres in the back: these are just some of the figures that verify the quantum leap between generations and that are confirmed by a generous feeling of space which can also be felt subjectively.
There is also considerably more luggage capacity than on the previous model: thanks to the variable design, 315 litres are available when the hood is closed - enough for two golf bags. There is still 246 litres of space with the hood down. A dimension that puts the Audi A4 Cabriolet clearly ahead of key competitors.
A standard load-through facility to the passenger area also increases the variability of the luggage compartment. Its cross-section of 190 x 280 millimetres provides enough space for up to three pairs of skis or two snowboards.
Not even the optional wind deflector takes up much space in the luggage compartment if not needed. Thanks to an ingenious design it can be folded up to hardly more than a quarter of its size and stowed compactly in the luggage compartment in its own bag.
The new Audi A4 Cabriolet also sets the standard in its class with a tank volume of 70 litres.
Powerful and refined: the engines
Two powerful V6 engines will provide the Audi A4 Cabriolet from launch with a level of propulsion befitting its class: the new 162 kW (220 bhp) three-litre V6 with aluminium engine block and continuous camshaft adjustment and the 2.4-litre version boosted to 125 kW (170 bhp) will be available at market launch. With a peak torque of 300 or 230 Nm respectively, they make supreme traction from any speed as much fun as swift acceleration from a standstill.
At the same time, both V6 engines are notable for their sporty six-cylinder sound and outstanding refinement - a combination that is extremely popular, especially with drivers of convertibles.
Both engines in combination with each driveline version comply with the strict limits prescribed by the EU4 emission standard.
The 3.0 V6
This is undoubtedly an appropriate top engine for such a dynamic and elegant convertible: the V6 develops 162 kW (220 bhp) from 2976 cc at 6300 rpm. Its peak torque of 300 Nm is available at 3200 rpm. It consequently accelerates the A4 Cabriolet with 5-speed manual gearbox from 0 to 100 km/h in 7.8 seconds, and on to a top speed of 243 km/h.
The average fuel consumption of this version is a mere 9.7 litres per 100 kilometres (1999/100 EC).
The supremacy of this engine is audibly expressed by its carefully composed, sporty sound. And the new design of the engine compartment, signalling a departure from plastic-shrouded drive units, is a visual reflection of the advanced technical calibre of Audi engines.
The design of the three-litre unit was determined not simply by the demand for more power, but also by the desire to create an even more refined engine. Its 90-degree layout is in any case among the smoothest-running available, as the free inertial forces are in equilibrium.
The 3.0-litre V6 delivers both high torque at low engine speeds and free-revving right up to its rated speed. Camshaft adjustment plays an important part here: the inlet camshaft can be gradually advanced by up to 42 degrees; on the exhaust side, the camshaft can be retarded as necessary by up to 22 degrees.
At just 1900 rpm the system switches to maximum valve overlap in order to achieve the highest torque possible: as a result, 90 percent of peak torque is available in a wide speed range between 2200 and 5200 rpm. And equally as impressive, the peak value of 300 Nm is reached at just 3200 rpm.
In parallel with camshaft adjustment, there is also the newly developed two-stage variable-length intake manifold. From 4200 rpm, the resonance tube reverts to the short, high-performance position; the maximum output of 162 kW (220 bhp) is finally reached at 6300 rpm.
The 2.4 V6
The other V6 engine that is available for the Audi A4 Cabriolet at launch, the 2.4-litre version, is also ideal for the task in hand. This engine is notable in particular for its superlative power characteristic combined with an outstanding level of refinement. Audi’s engine experts have comprehensively revised this tried-and-tested engine to prepare for its inclusion in the A4 model series.
It now has a maximum power output of 125 kW (170 bhp) and a peak torque of 230 Nm. Its effect is impressive: the A4 Cabriolet with manual 5-speed gearbox and 2.4 V6 accelerates from 0 to 100 km/h in 9.7 seconds; the top speed is 224 km/h. This contrasts starkly with an overall fuel consumption of just 9.7 litres per 100 km (1999/100 EC).
World first for a convertible: multitronic
The Audi A4 Cabriolet introduces a brand new dimension to transmission technology, unique in the convertible segment, in the form of the multitronic continuously variable automatic transmission. This transmission combines the dynamic and economical qualities of a manual gearbox with the convenience of an automatic. And the multitronic adds to these strengths with the unique experience of continuously variable acceleration.
The revolutionary multitronic can be combined with all current engine versions of the A4 Cabriolet. This makes it possible to cover a broader power spectrum: the multitronic can now even transmit torques of 310 Nm. Even the most powerful petrol engine available for the A4 series, the 3.0 V6 with 220 bhp and a peak torque of 300 Nm, is available with multitronic.
An infinite number of transmission ratios
So how does this revolutionary drive concept work? On all previous transmission types, whether manual or geared automatic transmission, specific transmission stages are physically present inside the transmission casing, in the form of five, six or more pairs of gears or planetary gear trains. On the continuously variable transmission, on the other hand, there is just one pair of sturdy gears with a flexible transmission belt, which permits an infinite number of transmission ratios.
This central component is known as the variator: a transmission element resembling a V-belt connects two axially adjustable sets of pulley halves. By adjusting the spacing between them in line with the circumference of the tapered pulley halves, the transmission ratio of this belt drive arrangement can be varied across a wide range.
Instead of the mesh belt that is otherwise commonly used on CVTs, Audi has opted for a link-plate chain made entirely from steel, but which is nevertheless almost as flexible as a V-belt.
It is sufficiently strong to be able to transmit much higher torques and forces than thrust belts. In tests extending over a number of years, this type of chain has proven extremely reliable and guarantees lifelong durability.
It consists of several metal links which are connected by steel pins. Their face ends press against the tapered surfaces in the variator. The chain’s tension is transmitted to the variator pulleys at these points of contact.
One fundamental advantage of the variator in the multitronic is the high spread of ratios. This means the difference between the largest to the smallest transmission ratio - 1:2.1 to 1:12.7.
This relationship of over 1 to 6 is close to the ideal value for transmissions. This on the one hand permits dynamic, sports-style acceleration thanks to the use of the highest possible ratio, and on the other hand fully exploits the engine’s potential for economical operation by using the lowest ratio.
Instead of using the hydraulic torque converter that is fitted on other CVTs to handle the tasks of pulling away - inevitably incurring some degree of loss in the slip phase - Audi has opted for an electronically controlled, oil-cooled multi-plate clutch.
In addition to its improved efficiency, this type of clutch permits a wide range of starting characteristics. In other words, the multi-plate clutch can be controlled in such a way that every conceivable form of pulling away is possible, from an ultra-gentle edging along on a slippery surface to sports-style acceleration at full throttle.
The electronics detect from the way the accelerator pedal is being operated whether the driver prefers an energy-conscious or performance-oriented style of driving, and either adapt the engine speed very gently, or push it into the peak engine torque range as rapidly as possible. The electronic-control clutch can even implement a warming-up program to bring the catalytic converter up to temperature more rapidly, with temperature-dependent speed increase upon clutch engagement.
A further special feature is the ability of the electronics to emulate the functions of a manual gearbox. Audi has opted for six forward speeds, which can be selected by the driver with a single touch of the selector lever in the second gearshifting plane, or activated at the push of a button on the steering wheel (optional extra).
These six speeds are stored as fixed gearshift programs. Depending on which speed the driver selects, the controller is supplied with the ratio as a setpoint, which it establishes at the variator and maintains.
Even these manually prompted gearshifts take place with pleasing smoothness and jolt-free, without any interruption in traction, all the while satisfying the desire for sports performance thanks to their continuous adaptation.
Light-footed and agile: the running gear
The sporting talents of the new A4 Cabriolet are by no means limited to the drive train department. The lightweight aluminium suspension, based on the much-praised axle design of the new A4 generation, provides the ideal basis for maximum agility and, consequently, sheer driving pleasure.
Four-link front suspension and trapezoidal-link rear suspension enable maximum steering precision and clearly defined handling with excellent cornering stability. Ride comfort also benefits from this ingenious axle design because a low unsprung mass also makes for a particularly sensitive response.
This is a general characteristic for which the A4 saloon has already received unanimous praise in the automotive press, and which is accentuated even more clearly on this new model. Audi’s development engineers have tuned the chassis components to improve sports performance even further. And they have also lowered the suspension - and consequently the centre of gravity - by 20 millimetres compared with the saloon and Avant models.
The rear suspension
Like the other versions of the Audi A4, the new Cabriolet generation comes as standard with one of the most complex and most efficient rear suspension systems currently available: the self-tracking trapezoidal-link rear axle.
The trapezoidal-link axle makes for top-quality ride comfort, coupled with the kind of dynamic performance that need fear no comparison with the competition.
The trapezoidal link is made from hollow-section aluminium. This torsionally and flexurally rigid control arm absorbs a large portion of the forces acting on the wheel. Together with the track rod located behind it, it determines the elastokinematic behaviour of the axle.
All wheel control elements pivot on the resiliently mounted subframe via rubber-metal mounts. These isolate axle vibration very effectively from the body. Moulded rubber mountings are also used for the coil springs between the trapezoidal link and the body’s longitudinal member. Here again, the choice of material and design provides excellent acoustic insulation.
The twin-tube gas-filled shock absorber is connected to the wheel carrier so that a direct-ratio effect is obtained. Combined with the separately mounted spring, this ensures a particularly sensitive response from the shock absorber.
The front suspension
With its precise, comfortable steering characteristics and road behaviour, Audi’s four-link front suspension layout set the standard compared with the competition. The advantage of this concept is that the steering axis - a virtual axis around which the wheel moves when turned - runs almost perpendicularly through the wheel’s centre. This means that virtually no driveline influences are felt at the steering.
In the new A4 generation, Audi’s suspension developers have now updated this highly advanced suspension concept by adopting numerous lightweight but very strong aluminium components.
On the four-link suspension layout, each wheel is located by four aluminium control arms. The swivel bearings are likewise now made from the same light alloy, a change which cuts weight by around 40 percent compared with the conventional version.
The subframe, on the other hand, represents the systematic application of lightweight steel design principles; the use of high-strength, thin-walled plates reduces the weight by around two kilograms.
Large-volume rubber components are used as the damper mounts on the new suspension design. This helps to isolate the shock absorbers acoustically.
The steering: precision and lightness
The new Audi A4 Cabriolet has hydraulically assisted rack-and-pinion steering bolted to the suspension-strut cross member.
The improvement can also be felt at the steering wheel: the driver registers this as greater precision and an even more spontaneous response to steering movements.
The six-cylinder versions of the new Audi A4 Cabriolet are fitted with damping valves integrated into the steering system. They reduce vibration of the steering wheel and its susceptibility to jolts as a function of steering-wheel angular velocity.
As with the entire running gear, the dictates of lightweight design even extend as far as the design of the steering wheels for the Audi A4 Cabriolet: for reasons of weight, the single-section skeletons are die-cast in magnesium.
Road behaviour: a policy of neutrality
Superb traction when coming out of even the tightest of bends; neutral, clearly defined self-steering characteristics and finally maximum agility - these were the main demands placed on the developers of the running gear for the new Audi A4 Cabriolet.
Such targets can only be attained by coordinating all elements to a high standard of precision. The role of the new self-tracking trapezoidal-link rear suspension in the overall package is of course particularly significant. Its elastokinematic steering properties promote above all the desired precision of response to effects on the steering, while significantly pushing back the handling limits.
On the circular test pad, the most revealing gauge of behaviour close to these limits, the Audi A4 Cabriolet needs only a slight increase in the steering wheel angle to remain on course at moderate to high lateral acceleration.
From the driver’s standpoint, the effect is clear enough: the Audi A4 Cabriolet remains unruffled even when close to the adhesion limits, and stays on the chosen line with controllable and strictly neutral behaviour.
At the same time, body movements even in S-bends remain moderate, without any of the loss of comfort that might be expected from this dynamically firm layout. This is because the spring rate has been raised to boost roll stiffness considerably - a positive effect that is maintained in a wide variety of load conditions.
Like all Audi A4 models, the Cabriolet is also fitted with the latest Electronic Stability Program ESP as standard. The system helps the driver to remain in control in potentially critical situations at the handling limits.
Hydraulic brake assist is also a standard feature of the latest ESP generation on the Cabriolet. Its task is to help the driver in emergency braking situations by automatically increasing braking pressure. This helps to reduce stopping distance considerably in hazardous situations.
Standard equipment
Audi also establishes a benchmark for this class with the new model’s equipment specification. Features such as the fully automatic hood and the active, automatically triggered roll-over protection device are supplied as standard on the Audi A4 Cabriolet. The hood can be ordered in the colours black, blue or red as required.
The standard specification also includes the deluxe automatic air conditioning with sun sensor and separate temperature selectors for the driver and front passenger, together with fog lights, heat-insulating glass and variable-height front seats with easy entry function.
Other standard features include electric front and rear windows and central locking with radio remote control, which also locks the glove compartment.
The Audi A4 Cabriolet is fitted with 16-inch - 7-arm - cast alloy wheels with 205/55 R16 (3.0: 215/55 R16) tyres. Over and above this specification, the top models with 3.0-litre engine have the Driver Information System DIS and a 4 spoke leather steering wheel as standard.
Each A4 Cabriolet has extensive storage space including drawers under the front seats and nets on the back of the front seats. The large load-through facility, another standard feature, can be used to transport skis or even two snowboards.
Anodised aluminium for the window capping strips, the cover on the hood compartment and the finish of the windscreen frame add sporty visual accents.
Comprehensive safety systems are a matter of course on an Audi Cabriolet. ESP with ABS and hydraulic brake assist, the Electronic Differential Lock EDL and Anti-Slip Regulation ASR guarantee maximum active driving safety. In addition to front airbags and head/thorax side airbags for the driver and front passenger, there are belt tensioners and belt force limiters for all seats. The Isofix child seat mounts on three seats mean that children can also enjoy open-air travel in safety. This is also the purpose of the standard function that enables the front-passenger airbag to be deactivated with the ignition key.
Optional equipment
In addition to the generous standard specification, an extensive range of extras - from xenon headlights to the Audi telematics traffic service - offers numerous possibilities for customising every A4 Cabriolet to suit each customer’s individual requirements.
A particularly popular feature among drivers of convertibles is a wind deflector, which effectively protects those travelling up front against air turbulence if the rear seat is unoccupied. If the wind deflector is not needed, it can be folded up and stowed compactly in the net on the luggage compartment bulkhead in the bag provided.
Comfort and driving pleasure can be enhanced with speed-dependent Servotronic steering (option). This regulates steering effort depending on speed. It conveys precise steering sensitivity with maximum feedback from the road at high speeds, and guarantees maximum possible assistance when parking.
Electronics - for information and entertainment
The new Cabriolet also provides the perfect infotainment experience. The four different audio systems are capable of covering wide-ranging requirements - no matter whether the customer opts for a radio-cassette player, CD changer or the high-grade BOSE sound system. Every system guarantees excellent sound quality, perfectly matched to the interior of the new A4. Even the most basic version comprises ten speakers and has an amplifier output of 150 Watt.
Nor is information given short measure. In addition to the symphony radio with Traffic Message Channel (TMC) facility, in Germany the new Audi telematics telecommunications system provides traffic information on request - tailored to the user’s requirements - in conjunction with an emergency-call and service function.
Two different navigation systems, which both use GPS satellite navigation, help the driver find the fastest route from A to B. The navigation system Plus is actually capable of performing intelligent, active route planning on the basis of TMC data and/or Audi telematics. On the basis of traffic congestion warnings, an alternative route recommendation is immediately calculated.
Communication in a broader sense likewise takes place while the car is being manoeuvred into a parking space: the Acoustic Parking System determines the exact distance to the next car - whether to the front or the rear - by means of ultrasonic signals. Sensors integrated discreetly into the bumpers measure the distance and prompt signals which let the driver know how much clearance remains.
A garage door opener saves homecomers the trouble of having to search for a separate remote control for the garage door. An integrated universal remote control replaces up to three hand-held transmitters with a single built-in component. Not only outside gates and garage doors respond to the radioed commands, it is also possible to control compatible security systems and lighting installations on a building.
Audi has also further improved protection against car theft on the A4 Cabriolet. The optional anti-theft device includes an alarm siren with its own power supply, which still even triggers an alarm when the car battery is removed. The system can only be deactivated by a radio signal from the car key.
Customers have the tantalising choice of 14 different paint colours, including ten particularly stylish metallic or pearl effect versions. Seven different 16-inch and 17-inch cast aluminium wheels, with tyres up to 235/45 R17, create a wide variety of sporting accents.
And while on the subject of sport, even a car as dynamic as the new Audi A4 Cabriolet may arouse the desire for a setup that makes even fewer compromises. The accessories range also caters for such a demand.
Specially developed sports suspension with firmer shock absorber/spring rates, for instance, puts the focus on the Cabriolet’s sporting potential.
Individuality in the interior
And there are numerous different ways in which the interior can be given an individual look. Cloth/leather, leather and leather/Alcantara seat upholstery are just three options which visibly and palpably underline the special status of the new Audi A4 Cabriolet. High-quality inlays in three different types of wood round off this luxurious ambience.
On warm days the optional cooling box in the glove compartment is very useful: the contents are cooled by the automatic air conditioning while the car is on the move and also remain at a low temperature for some time after the engine has been switched off.
The standard seats in the A4 Cabriolet provide maximum comfort on long journeys. However, they can be customised to meet your individual requirements even more perfectly, for example with a 4-way electric lumbar support for both front seats. Individually adjustable heating can be ordered for all four seats.
The sports front seats in the range of optional extras for the A4 Cabriolet offer an ideal combination of excellent lateral support and maximum seating comfort. They can also be combined with electric adjustment and a memory function as an option. This also applies for the exterior mirrors.
A growing segment: The Audi A4 Cabriolet and the market for four-seater convertibles
When the last Audi Cabriolet left the production line in July 2000, a very special success story came to an end. Even more impressive than the 72,000 Audi Cabriolets built is the growth that has taken place in the four-seater premium convertible segment. A segment that the Audi Cabriolet has played a major role in defining and evolving.
Compared with just 7,675 cars sold in this category in Germany in 1990, 24,899 models were sold in the year 2000. The same trend can be identified worldwide: sales over the past decade have increased from 20,840 to more than 80,000 four-seater convertibles. An increasing number of manufacturers, including several of the most famous European companies, have put their own four-seater convertibles on the market.
So what makes this segment so successful? This success is due to characteristics that were already hallmarks of the Audi Cabriolet and which the new Audi A4 Cabriolet unites in even more sophisticated form: sports character and elegance, luxury and excellent suitability for everyday use.
It is therefore not surprising that almost 44 percent of European customers gave design as the reason for buying the Audi Cabriolet: this is the result of a survey from the year 1998, when the Cabriolet was already in its eighth year of production. This is the clearest evidence not only of the fact that the vehicle’s styling still never fails to impress, but also of its continuing success as a trendsetter.
A further factor contributing to the success of the Audi Cabriolet was its extensive range of engines. Around 37 percent of customers opted for six-cylinder engines in 1999, a clear indication of the acceptance of the premium status of the Audi Cabriolet. The decision to offer the new A4 Cabriolet with two powerful six-cylinder engines at market launch also takes account of this status.
A unique feature in the convertible segment is multitronic which is available for all engine versions offered at launch. This continuously variable automatic transmission combines the dynamism and efficiency of a manual gearbox with the convenience of a conventional automatic transmission. It is therefore possible for drivers to cruise along smoothly without hectic use of the pedals - a driving style preferred by drivers of convertibles - or to adopt a distinctly sporty style. A combination which has never before existed in the convertible segment.
The most important target group for the new Audi A4 Cabriolet is the age group of 30-39 year olds. Potential customers include both two-car families and singles or young couples without children. Freelancers and self-employed people account for around 40 percent of the target group in Germany and approximately 60 percent in Great Britain.
One thing that all target groups have in common is a higher than average monthly income in excess of 4600 euro and a high social status. Such potential customers also have a marked appreciation of quality and brand awareness, value their free time and are not averse to being the centre of attention.
Women account for around 25 percent of customers in both Germany and Europe. More than two thirds of all customers own other cars in addition to the Audi Cabriolet.
The most important sales markets for the new A4 Cabriolet are North America, Germany and Great Britain. Around two thirds of the planned production total of 15,000 units per year are destined for export markets.
[source: audi-mediaservices.com]
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