The drivetrain and chassis of the new Audi S4* and S4 Avant* were thoroughly redeveloped – this also applies to the gentle, fast and spontaneously shifting eight-speed tiptronic. The layout of its gear sets and shifting elements results in low drag torques and thereby to a high efficiency level. Its large number of gears makes it possible to operate the engine close to its ideal load point very frequently. Their lower gears have short, sporty ratios, while the upper gears are long to reduce revs and fuel consumption.
The classic automatic transmission is integrated into the engine’s thermal management system and is designed for start-stop operation (from 3 km/h (1.9 mph) residual speed). The driver can select the D, S or E mode and can use shift paddles on the steering wheel for manual gear changes. All commands are transmitted to the transmission electrically – by wire. A new engine speed-adaptive vibration absorber makes engine running even smoother at low speeds.
If the driver releases the accelerator pedal between 55 and 160 km/h (34.2 - 99.4 mph), the transmission switches to freewheeling, provided that this enables fuel savings (not in S mode). If the optional predictive efficiency assistant and adaptive cruise control Stop&Go including traffic jam assist are installed, the coasting function is very predictive.
Traction, dynamics and safety: quattro drive is standard
The quattro permanent all-wheel drive system with its asymmetrically dynamic layout makes a large contribution toward sporty and stable handling of the new Audi S4* and S4 Avant*. During normal driving, its all-mechanical center differential directs 60 percent of the torque to the rear axle and 40 percent to the front. If slip occurs at one axle, most of the forces are rapidly redirected to the other axle – up to 85 percent to the front or up to 85 percent to the rear axle. These high locking figures enable a clearly defined torque distribution and precise interplay with control systems.
Torque vectoring – an intelligent software function – complements the work of the quattro drive system. In dynamic cornering, it applies minimal brake interventions at the wheels on the inside of the curve before they begin to spin.
These interventions are made even if the driver does not press the accelerator pedal. The difference between propulsive forces at the wheels makes the car turn into the curve ever so slightly – making handling even more precise, agile and stable.
Torque vectoring at the rear axle: the sport differential
The optional sport differential provides even more dynamic performance. It uses two superposition gears to variably adjust the distribution of torque between the wheels of the rear axle. In fast curves, it literally pushes the car into the radius. Its management, which runs on the newly conceptualized electronic chassis platform (ECP), is incorporated into the Audi drive select handling system. The sport differential performs even quicker than in the previous model, and it is around one kilogram (2.2 lb) lighter.
The chassis of the two new S models is based on two newly developed five-link suspensions, front and rear. The axle principle enables optimal absorption of longitudinal and transverse forces. Its mounts are sporty-stiff in a lateral direction and supple and soft longitudinally. Together with the further developed, electro-mechanical power steering – with direct steering ratios – the mounts create the right conditions for dynamic handling, good comfort and a high degree of stability. With their low weight, the new parts also reduce fuel consumption. As an option, Audi can install dynamic steering, which adapts its steering gear ratio to the vehicle’s driving speed and steering angle.
Up to five modes: Audi drive select
The Audi drive select handling system is standard equipment in the new Audi S4* and S4 Avant*. It intervenes in control of the engine, steering, eight-speed tiptronic, sport differential and optional chassis with damper control that adds the CDC (continuous damping control) damper. The driver can control the characteristics of these units by choosing the comfort, auto, dynamic or efficiency mode or the individual mode (if a navigation system is installed). Both the controlled chassis and the standard S sport chassis lower the body ride height by 23 mm (0.9 in) compared to the A4 base model.
The brakes are dimensioned to be large. At the front wheels, the internally-vented discs are 350 mm (13.8 in) in diameter. They are gripped by black (or optionally red) painted six-piston fixed calipers with S lettering.
Audi delivers the new S4* and S4 Avant* models with standard 18‑inch wheels in a five twin-spoke star design, and the tires are size 245/40. Optional 19‑inch wheels are available from quattro GmbH. Electronic stabilization control (ESC) operates even more precisely and sensitively than in the previous model. The driver can choose to deactivate it over two stages (partial or full deactivation).
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.