Audi S6 and S7 confirmed for Oz

Audi has released details for the new S6 and S7 models, including the advanced new turbo-diesel V6 and its electric supercharger.

Unfortunately, the exotic new diesel powerplant won't be offered in Australia. Instead, customers for the Audi S6 and S7 will be taking delivery of petrol-powered vehicles, just like the rest of the world outside Europe.

At least the turbocharged petrol models for Australia will produce 600Nm and will feature the 48-Volt mild-hybrid electrical system and Electronic Chassis Platform of the Euro models. According to Audi Australia, the S6 sedan and the S7 Sportback will definitely launch locally, with the importer also considering the S6 Avant (wagon), despite the fact that the vehicle on which it's based – the A6 Avant – will not go on sale here.

While 600Nm sounds more than just a little bit punchy, the Europe-only diesel engine beats that figure by another 100Nm. And the diesel's electric compressor forces more air into the engine sooner – like a traditional supercharger – but without the efficiency losses associated with that type of forced induction.

Being electric, furthermore, the compressor spools up as soon as the driver demands, rather than waiting around for exhaust gases to spin a turbine, as is frequently the case with turbocharged engines caught off boost at low revs.

Audi claims that the 3.0-litre diesel V6, which is reliant on the 48-Volt electrical system for the boosted charge, produces its 700Nm peak across a range of engine speeds from 2500 to 3100rpm.

Yet fuel consumption figures in the WLTP combined-cycle test are miserly, ranging from 6.2 to 6.3L/100km for the S6 sedan and up to 6.5L/100km for the S6 Avant (wagon) and S7 Sportback.

The EPC (electric-powered compressor) can reach maximum speed of 70,000rpm and begins pumping air within 250 milliseconds of the driver stamping the accelerator pedal. At 1650rpm, a conventional turbocharger picks up the load, with the EPC remaining available for additional boosting when engine revs fall back and exhaust gases to spin the turbine dwindle.

As well as powering the EPC, the 48-Volt electrical system also underpins a mild-hybrid system which permits the vehicle to coast for up to 40 second and thus save fuel. A belt alternator starter (BAS) is connected to the engine's crankshaft and recovers 8kW of power during acceleration, for storage in a 10Am lithum-ion battery under the boot floor. As soon as the driver presses the accelerator again, the energy stored in the battery is discharged to the BAS, which restarts the engine. According to Audi, coasting can occur from a speed as low as 22km/h.

Mustering peak power rated at 257kW, the diesel V6 drives through an eight-speed automatic transmission to all four wheels. Audi claims that the flatter torque curve results in fewer occasions the transmission is forced to change down. The claimed 0-100km/h time is 5.0 seconds for the S6 sedan and 5.1 seconds for the two liftback models (S6 Avant and S7 Sportback). A centre differential can split torque in a ratio of 40:6, with up to 70 per cent of drive available to the front wheels and up to 85 per cent directed to the rear. The rear axle runs a sport differential also.

Dynamics are enhanced, according to the manufacture, with the option of all-wheel steering. Also optional is a ceramic brake package. Both that option and the standard brakes feature six-piston calipers at the front.

Adaptive air suspension fitted to the S models for the first time can lower the ride height up to 20mm for the S6 by and up to 10mm for the S7. All three variants ride on 20-inch alloy wheels shod with 255/40 R20 tyres. Audi also offers optional 21-inch wheels.

As standard, the S models are equipped with the following comfort and convenience features: MMI infotainment with virtual cockpit, four-zone climate control, Alcantara sport seats (S6) and super sport seats (S7).

Audi will launch the new S6 and S7 models in Europe for the northern hemisphere summer – just months away. Australian deliveries with the 2.9-litre TFSI petrol V6 will follow later.