Drivetrain
A six-speed manual transmission is standard on the Sedan and Avant models with front-wheel drive; most variants offer continuously variable multitronic as an option. The quattro versions have either the manual transmission or (as of the 2.0 TDI with 130 kW (177 hp)) the seven-speed S tronic on board.
The innovative thermal management system shortens the warm-up phase of the manual transmission, among other things, and thereby reduces friction loss. Audi claims all transmissions are distinguished by convenient and precise operation, high efficiency and a wide spread of gear ratios – the long ratios in the higher gears reduces fuel consumption, while the short ratios in the lower gears benefit the dynamics.
The quattro permanent all-wheel drive is standard on the A4 allroad quattro, and available in the Sedan and Avant from the 2.0 TDI with 105 kW (143 hp). The A4 family uses the self-locking center differential here. In regular driving operation it primarily transmits the engine torque to the rear wheels in the ratio of 40 to 60. If necessary, redistribution occurs within the shortest possible time. The torque vectoring function supplements the work of the center differential with finely incremented brake applications, to make handling even more precise and safer.
In the V6 quattro variants Audi offers the sport differential as an extra, lending maximum precision and high traction to the A4 when cornering at the handling limits. The high-end component actively distributes the power between the rear wheels as required.
Chassis
Engineers at Audi have again striven to find the best balance of sporty precision and ride comfort. The mounts of the rear suspension control arms and the characteristics of the shock absorbers have been even more finely tuned. Most of the components of the five-link front suspension and the trapezoidal-link rear suspension are made of aluminum.
The electromechanical power steering is all new. It offers better feel for the road surface and slight brake applications counteract pulling to the side on unevenly slippery surfaces.
Drive modes on offer include “comfort,” “auto,” “dynamic”, “efficiency” and if there is an onboard navigation system, the additional “individual” mode.
Dynamic steering offered as option, that using a superposition gear adjusts the gear ratioin a continuously variable manner depending on the driven speed; at the handling limits small interventions compensate for understeering and oversteering.
All front-wheel-drive versions of the A4 feature the electronic stabilization program (ESP) with electronic limited slip differential.
As with other German manufacturers there’s a host of driving assistance systems including adaptive cruise control.
The Audi S4
The Audi S4, available in the Sedan and Avant versions, employs the most powerful engine in the line – the 3.0 TFSI with 245 kW (333 hp) and 440 Nm (324.53 lb-ft) torque. The Sedan’s average fuel consumption is a mere 8.0 liters per 100 km (29.40 US mpg) – with an impressive performance: The S4 accelerates in 5.0 seconds from zero to 100 km/h (62.14 mph) and achieves an electronically limited maximum speed of 250 km/h (155.34 mph).
The modified Audi S4 is identifiable from the changes to the headlights, the bumpers, the air inlets and colors. The interior also contains subtle changes in appearance. The S sport suspension and 18-inch wheels featured on the S4 deliver outstanding road grip.