Audi S6 2019 first drive

The easy way to view the arrival of the new Audi S6 is as a new and enticingly warmed-over executive four-door, a decent progression from its predecessors but nothing more controversial than that.

The new S6 – like its close relatives being launched at the same time, the S6 Avant estate, S7 Sportback and SQ5 soft-roader – gets its extra performance from a brand new 48V mild-hybrid powerplant whose heart is a new turbocharged 3.0-litre V6 diesel engine. And diesels, as we know, are in sales decline in the UK following Dieselgate and publicity over the danger to human health caused by exposure to untreated diesel exhaust constituents, principally NOx.

Thus the far more intriguing story is about Audi launching a new generation of S6 models that depend on a form of motive power already discredited in some vocal quarters. There won’t be an S6 petrol alternative offered here. The new cars may well deserve customers but, to succeed, they’ll need to buck a strong market trend.

Audi naturally deploys good arguments to back its move: it cites the low CO2 output of diesels compared with petrols and the fact that the latest exhaust treatment paraphernalia makes 2019 diesel exhausts cleaner than the EU requires (and capable of passing the looming Euro 7 standards). Of course, their impressive fuel economy and generous touring range help many drivers, too.

The heart of the S6 is a north-south nose-mounted 3.0-litre V6 equipped with a 48V electrically driven compressor whose output keeps the turbocharger spinning, even when the crankshaft speed is low, to cut spool-up time and reduce accelerator lag. The system also incorporates a 48V belt-driven integrated starter-generator that under acceleration contributes to peak outputs of 344bhp at 3850rpm and 516lb ft of torque at 2500-3100rpm. When the car is coasting or on the overrun, it collects power in a 0.48kWh battery for later use in acceleration.

The hybrid power is directed through an eight-speed dual-clutch automatic gearbox to a permanent four-wheel-drive system, which at extra cost can be specified with a sport central differential to sharpen the car’s agility in corners.

Audi says the mild-hybrid part of the powertrain contributes around 2-3mpg to real-world fuel consumption and helps the whole system run cleaner. The official WLTP combined fuel consumption figure is 36.2mpg and the CO2 output is 164g/km – both impressive results for a five-metre, two-tonne saloon that can pull a 5.0sec 0-62mph time and reach a governed 155mph in very short order.