The new A4 and A4 Avant blend great talents: dynamic handling and a comfortable ride approaching the level of the next higher automobile category. The Audi engineers developed a new suspension system for this model series with a focus on systematic lightweight construction and precise responses.
A further enhanced five-link front axle is used, the principle of which allows optimal absorption of longitudinal or lateral forces. The mounts are designed to be stiff and sporty in the lateral direction but smooth and soft in the longitudinal direction. Vibrations are consistently eliminated with the use of a hydromount, which ensures excellent comfort along with a high degree of agility.
In order to achieve optimal stiffness, the upper links are integrated directly into the bodywork, unlike on the previous model. All axle links, the pivot bearing and the damper stilts are made of forged aluminum. The lightweight concept is completed with the use of monotube dampers and high-strength, thin-wall tubular stabilizer bars and segmented wheel hubs. Compared with the previous model, the weight of the front axle has been reduced by six kilograms. The lower link level is attached with newly designed rubber mounts to a hybrid subframe made of high-strength and aluminum. The stiff installation of the subframe in the front of the body minimizes vibrations and provides the foundation for optimal agility.
3.5 kilograms (7.7 lb) lighter: the electromechanical power steering
Audi also decided on all-new electromechanical power steering, saving 3.5 kilograms (7.7 lb) compared with the previous model. It consumes very little energy and has a direct, sporty ratio of 15.9:1. Power assistance is based on the car’s current speed. The steering provides very exact feedback from the road, responds spontaneously and is very precise. The new electromechanical power steering is functionally connected with some of the new driver assistance systems such as the Stop&Go adaptive cruise control including traffic-jam assist.
Dynamic steering is available in combination with engines of 110 kW (150 hp)* and above. Through the use of superimposed gearing, its ratio varies by up to 100 percent, depending on the car’s speed and the mode selected in the Audi drive select driving dynamics system. Vehicle stabilization is supported by lightning-fast steering impulses, further enhancing stability and safety.
The new rear axle
In the rear of the new Audi A4 and A4 Avant, a five-link axle replaces the trapezoidal-link axles of the previous model. By means of an intelligent combination of materials, the weight of the axle components has been reduced by another five kilograms.
Low unsprung mass provides a sporty driving experience, and together with the new damper and elastomer tuning, it allows a smooth ride, excellent body control and improved wheel damping and control. For the first time, monotube shock absorbers have been used, resulting in a further weight reduction.
The axle is insulated from the body with hydraulically damped axle mounts. This reduces the shocks from the road surface significantly while maintaining lateral guidance. Additional measures for the reduction of fuel consumption are friction-optimized wheel bearings and aero-deflectors that reduce roll and wind resistance.
Central suspension control unit – the electronic suspension platform
A central suspension control system has been applied to achieve ideal interaction between the various driving dynamics systems. This highly integrated control device was specially developed for the new A4 line. It processes all the information relevant for driving dynamics, from which it calculates the driving situation and the current road surface frictional coefficient. This information allows optimal control of the system for highly precise, dynamic handling and maximum ride comfort.
Broad spectrum: suspension with adjustable shock absorbers
As an alternative to the standard tuning with highly sensitive monotube shock absorbers, Audi has equipped the new A4 and A4 Avant with two suspension systems that utilize variable damping; one focuses on comfort and the other on sporty driving. Sensors measure the movement of all four wheels as well as longitudinal and transverse acceleration. The shock absorbers are then adjusted to the road-surface conditions and driving situation accordingly. This results in enhanced driving dynamics with even more comfort. In addition, the driver can choose the basic suspension setting by pressing a button in Audi drive select, so that the desired characteristics are always available.
This is made possible with newly developed CDC (continuous damping control) shock absorbers with electromagnetically controlled valves in their pistons. They allow hydraulic fluid to flow faster or more slowly as required. A new operating concept makes them very energy efficient. The central suspension control unit processes all sensor signals within milliseconds and controls each shock absorber individually. Together with the wide range of the damper valves, this ensures a wide spectrum between a soft rise and firm handling.
When suspension with variable shock absorbers is installed, the car body is 10 millimeters (0.4 in) lower than with a normal suspension in the comfort setting and 23 millimeters (0.9 in) lower in the sport setting.
Audi drive select
Like the suspension with variable shock absorbers, quattro drive with sport differential (available as of 2016) and dynamic steering belong to the optional components for the new A4 family whose control is included in the optional Audi drive select system (standard equipment as of 140 kW/190 hp).
In the basic configuration, the driver can use this system to regulate the behavior of accelerator pedal, automatic transmission, steering, cruise control or adaptive cruise control (ACC) and automatic air-conditioning in various modes, named Comfort, Auto, Dynamic and Efficiency. In connection with a navigation system, there is also the mode Individual, with which the driver can adjust each system as desired.
Standard equipment for the new A4 and A4 Avant in the base line includes 16-inch or 17-inch light-alloy wheels (depending on the engine); 17-inch cast aluminum wheels are fitted with the design and sport lines. Audi and quattro GmbH offer optional wheels ranging from 18-inch cast aluminum flow-forming wheels (standard equipment with the S line sport package and with design selection) to 19-inch diameter. An aerodynamically optimized version is offered of the 16 and 17-inch wheels.
All the wheels Audi offers for the A4 line are extremely light and their low unsprung mass contributes to the sporty driving experience. All tires have optimized roll resistance. A repair set and tire-pressure monitoring are standard equipment with the option of a space-saving reserve wheel.
A wide range of brakes are fitted on the various models. The A4 models with the TDI engine up to 120 kW (163 hp) and the TFSI up to 140 kW (190 hp) and 16-inch wheels have brake discs with floating calipers. The models with the most powerful engines and 17-inch wheels have brake discs with especially light fixed aluminum calipers. The new brakes are approximately five kilograms (11 lb)lighter than those of the previous models.
The front axles are fitted with internally ventilated brake discs of up to 338 millimeters (13.3 in) in diameter. The electromechanical parking brake is integrated into the rear axle and features new holding and starting functions.
Many aspects of the Electronic Stabilization Control (ESC) have been further developed; it now operates with even more precision and sensitiveness than on the previous model. In the dynamic mode, engine intervention is largely deactivated and brake intervention is slightly reduced.
*The fuel consumption and CO2 emission figures of all models named above and available on the German market can be found in the list on the last page of this basic information.