The Audi A8 L offers all the comfort of a luxurious sedan together with sporty handling. Its sophisticated chassis combines high precision with supreme stability and excellent ride characteristics. The adaptive air suspension with controlled damping and the Audi drive select dynamics system are standard, with dynamic steering available as an option.
All wheel control arms and many other components are made of aluminum. The track measures 1,644 millimeters (64.72 in) up front and 1,635 millimeters (64.37 in) at the rear. The front suspension comprises five links per wheel – two transverse links on the upper plane, the support link and control arm in the lower plane and the track rod. All suspension control arms are forged aluminum parts, guaranteeing low unsprung masses. The anti-roll bar fabricated from a high-strength tube also saves weight.
The five-link suspension can handle longitudinal and lateral forces separately. Their bearings are stiff in the lateral direction, fostering sporty precision; on the other hand, the bearings are remarkably pliable in the longitudinal direction.
The subframe for the engine and the front axle serves as the backbone of the front suspension. It is made of high-strength steel and is reinforced with x-shaped struts. Because it is rigidly bolted to the front end of the car, it becomes an integral component of the body. The high rigidity ensures that steering forces develop without delay.
The bearing pedestal, which connects the upper control arms, and the pivot bearing are made of aluminum. A diecast strut brace further enhances the rigidity of the front of the car.
Efficient: the servotronic steering
All A8 L models leave the factory with servotronic power steering on board, which adapts its power assist to the speed being driven. It is extremely precise and delivers sensitive feedback. It features a sporty and direct 16.1:1 ratio.
It receives its hydraulic energy from a regulated vane-type pump, which provides only as much fluid as is required for the respective operating point. This reduces fuel consumption by approximately 0.1 liters per 100 km.
The steering gear – a rack-and-pinion construction– is mounted on the subframe down low and far to the front. Steering input is communicated to the wheels very directly via the track rods. The steering column is bolted in a rotationally-fixed manner to the body.
The rear suspension of the new Audi A8 L is designed according to the track-controlled trapezoidal link principle, a compact design that ensures superior driving and comfort qualities. The two hollow trapezoidal links are warm-hardened aluminum castings; the wheel carriers are of chill-cast aluminum. The top transverse links and the track rods are aluminum forgings; the stabilizer bar is also a tube.
The struts act directly on the wheel carriers. This allows a high damping ratio so that the dampers react sensitively. The developers were also able to redesign the axle beam bearings to be more comfortable. The beam comprises two steel longitudinal and lateral beams each; four hydraulic bearings connect them to the body.
Supple: the adaptive air suspension
The A8 L comes standard with the adaptive air suspension, which combines a high-end air suspension with controlled damping. It enables the luxury sedan to remain composed and smooth on all types of uneven road surfaces. The air supply system is located in the rear of the car. The compressor works with a pressure of 18 bar and fills a 5.8 liter pressure vessel. The struts have been newly developed; their increased air capacity now allows a soft characteristic and a fine response even without an auxiliary accumulator.
The friction of the regulated dual-tube shock absorbers, inside which the air springs are located, was reduced by around ten percent. Supplied with data from a complex system of sensors, the control unit adapts the function of the shock absorbers to the road conditions, the driver’s style, and the mode specified in the Audi drive select system. Individual adjustments for each wheel are made continuously by the millisecond via the control current for the damper valves.
The driver can choose between four operating modes for the adaptive air suspension using Audi drive select. The ride height of the body changes depending on the mode selected. In “auto” mode, it is lowered by 20 millimeters (0.79 in) when the A8 L has driven for longer than half a minute at a speed greater than 120 km/h (74.56 mph). This increases stability and reduces wind resistance, thus saving fuel. The body is not lowered in “comfort” mode.
In “dynamic” mode, on the other hand, the body is lowered 10 millimeters (0.39 in) from the outset, with the ride height lowered another 10 millimeters when the 120 km/h (74.56 mph) threshold is reached. In “lift” mode, ground clearance increases by 25 millimeters (0.98 in) from the standard ride height so that smaller obstacles can be overcome. The adaptive air suspension is also used to level ride height. Audi also offers the A8 L with an optional setup that emphasizes stiffness. The adaptive air suspension sport lowers the ride height in standard mode by 10 millimeters (0.39 in).
Incredible scope: Audi drive select
Another high-end feature in the Audi A8 L is the Audi drive select system, which extends the scope of the entire driving experience by an incredible amount. In the standard version, it integrates the adaptive air suspension, the eight-speed tiptronic, the servotronic power steering, the Audi pre sense basic safety system and the engine control unit. The system modifies the characteristics of the shock absorbers, the air springs and the accelerator, and adapts the shift points, power steering boost, and the trigger time for the belt tensioners.
The driver can vary the function of these components between the three modes “comfort,” “auto” and “dynamic.” Drivers can – within certain limits – also compose an “individual” mode corresponding to their own personal ideal by choosing settings from the portfolio.
Audi drive select proves to be very versatile in the new A8 L. Additional optional components – the sport differential for the variable distribution of power between the rear wheels (standard in the 4.2 TDI), adaptive light, ambient lighting and dynamic steering – can also be integrated into the system.
Dynamic steering is another high-end Audi feature. It uses a superposition gear to vary the steering ratio by nearly 100 percent as a function of driving speed and the setting in Audi drive select. In city traffic it is very direct; at highway speeds it is indirect to avoid unnecessary constant steering adjustments. At the cornering limit it minimizes oversteer and understeer by automatically countersteering with tiny steering inputs. It also prevents the car from pulling to one side when braking on surfaces with different friction values.
The dynamic steering needs less time for its corrections than the brake system needs to develop pressure at the wheels. In many cases it does most of the work without the driver ever noticing, eliminating the need for numerous braking actions.
The Audi A8 L comes equipped with a powerful, durable and lightweight brake system. All discs are inner-vented. Stainless steel pins connect the friction rings, which are made of a newly developed cast iron material, to the aluminum brake caps – a concept from sports car design that prevents the transfer of temperature peaks, reduces the risk of fading and reduces the weight by as much as four kilograms (8.82 lb). Optional ceramic brakes that are extremely lightweight, robust and durable will be available from Audi at a later time.
The standard brake discs have different diameters depending on the engine. The front discs measure 365, 380 or 400 millimeters (14.37, 14.96, 15.75 in); the rear discs 330 or 356 millimeters (12.99, 14.02 in). Two-piston (six-piston in the W12) calipers are used up front and single-piston calipers in the rear. The calipers of the W12 are painted matt black. The auto release function, standard on the A8 L, makes it easier to start out on slopes.
The ESP stabilization system offers a sport mode. In this mode, engine intervention is largely deactivated and brake intervention somewhat reduced. This allows experienced drivers to move the sedan very dynamically on winding roads. The standard tire pressure indicator is also integrated into the ESP.
The Audi A8 L rolls on large wheels. The V6 versions sport 17-inch alloy wheels shod with 235/60 tires. With the V8s, the sizes are 18 inches and 235/55, and the W12 stands on 19-inch wheels with 255/45 tires. Optionally available from Audi are wheels and tires between 18 and 21 inches in attractive designs – semi-polished, polished, high-gloss polished, machine-polished finish, two-color and titanium look.
Run-flat tires are available for the 19-inch wheels. The range of winter tires extends from 17 to 20 inches. A tire repair kit comes standard; a space-saving spare tire is available for an additional charge.
The equipment and data specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.