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Audi A5 Sportback: FWD, AWD quattro & gearboxes (5/7 >)

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Continued - The new Audi'A5 Sportback is launched with three transmission choices.

The 2.0 TFSI (132 kW / 180 hp and 155 kW / 211 hp), the 2.0 TDI with 125 kW (170 hp) and the 2.7 TDI (140 kW / 190 hp) come standard with a six-speed manual transmission (graph below). They will be followed by the manual 1.8 TFSI entry model and the 3.0 TDI.

 Multitronic

The multitronic continuously variable automatic transmission, which offers a sport mode and a manual mode with eight simulated gear ratios (electronically set up) will follow shortly after the launch with the 2.0 TDI (105 kW, 143 hp), the 2.7 TDI (140 kW / 190 hp) and both versions of the 2.0 TFSI (132 kW / 180 hp and 155 kW / 211 hp).

 7-speed S tronic

A5 Sportback 2.0 TDI with the 6-speed manual gearbox.

A5 Sportback 2.0 TDI with the 6-speed manual gearbox.

 

The all-wheel drive versions of the 2.0 TFSI quattro, the 3.2 FSI quattro and the 3.0 TDI quattro get the seven-speed S tronic dual-clutch transmission which changes gears within a few hundredths of a second. Its efficiency and long ratio in seventh gear benefit fuel consumption. The driver can let the seven-speed S tronic shift automatically or select the gears via rocker switches on the steering wheel.

The seven-speed S tronic is made of two separate transmissions and integrates two nested multi-plate clutches that control the various gears. The outer clutch directs the torque via a solid shaft to the gear wheels for the gears 1, 3, 5 and 7. The inner clutch directs the torque via a hollow shaft revolving around the solid shaft to the gear wheels for the gears 2, 4 and 6 as well as reverse.

Both transmission structures are continuously active, but only one is connected to the engine at any one time.

For example, when the driver accelerates in third gear (1st transmission structure), the fourth gear is already engaged in the second transmission structure. The gear change occurs by changing the clutches. The mechatronics module, a compact block comprising controllers and hydraulic actuators, controls all shift and clutch operations with precision, even when manoeuvring centimetre by centimetre.

 AWD quattro

Audi A5 Sportback quattro chassis and drivetrain (all-wheel drive versions).

A5 Sportback quattro chassis and drivetrain, all-wheel drive (FWD versions).

 

With the quattro permanent all-wheel drive system, power flows from the output shaft to the centre differential, which normally sends 60 percent of torque to the rear differential and 40 percent to the front one. The 60% rear bias gives the sporty feeling of power being delivered from the back of the car, rather than pulling it from the front.

However, the 60/40 rear/front distribution ratio changes when a wheel begins to slip, as the mechanical centre differential automatically transfers most of the power to the axle with the better traction. Up to 85 percent can be directed to the rear wheels and up to 65 percent to the front ones.

Shortly after the A5 Sportback is launched, Audi will introduce a manual transmission and quattro drive paired with a 2.0 TDI producing 125 kW (170 hp) and a 2.0 TFSI with 155 kW (211 hp). The 3.0 TDI quattro, equally with six-speed manual transmission, will also become available at this point.

 Sport differential

A new optional (rear) sport differential is available for the 3.0 TDI quattro and the 3.2 FSI quattro. In addition to the standard 60/40 rear/front distribution in the centre differential, the optional sport differential distributes the drive power in continuously variable proportions between the rear wheels.

Audi A5 Sportback quattro sport differential.

Audi A5 Sportback quattro sport differential.

When steering into or accelerating in a curve, the sport differential sends most of the torque to the outside wheel, literally pushing the car into the curve. It promptly prevents oversteer or understeer, since its short reaction time of under 100 milliseconds is faster than the ESP stabilization program. Audi says that it even reacts just as effectively while coasting as it does under load.

With the sport differential, a superposition gear comprising three gear wheels is added to both the left and right sides of the classic differential; it rotates ten percent faster than the drive shaft. A multi-plate clutch actuated by an electrohydraulic actuator provides the power connection between the shaft and the 10% faster-running superposition gear.

When the clutch closes, it forces the higher speed of the superimposed gear onto one of the wheels. The additional torque is drawn off of the opposite wheel via the differential. In this way nearly all of the torque can be directed to one wheel. The maximum difference between the wheels is 1,800 Nm (1,327 lb-ft).

The fast reaction speed of the system lies in a proprietary Audi management software. The controller quickly recalculates the best distribution of the forces for each driving situation as a function of the steering angle, yaw angle, lateral acceleration, speed and other information.

The optional sport differential is integrated into the Audi drive select dynamic control system, and its function can be adapted to three modes: the “comfort” mode, which is primarily focused on safety and stability, the “auto” mode and the more sporty“dynamic” mode.

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