► S6 moves to diesel power...
► ...but it actually suits it
► A five-star car
If you’ve drifted away from diesel in recent times, here’s a sports saloon to make you fall for the fuel all over again: the new Audi S6. These sub-RS models have always previously been petrols – and this new one still is outside Europe – but the latest S6 will be purely turbodiesel when it goes on sale in the UK in 2019.
You’ll pay around £60,000 for the saloon, and £2k more for the Avant estate – both figures currently TBC. It’s a brave move from Audi given diesel’s terrible press, but our first drive in Germany suggests the S6 is an exceptional all-rounder that merits its creators’ (very) cautious confidence.
What’s the spec?
The 3.0-litre turbodiesel V6 is based on the one in the Audi A6 50 TDI, and gets the same mild hybrid system too. The S6 can coast for up to 40 seconds, activate its stop-start system at up to 13mph, and harvest energy normally wasted under braking, then store it for later in a compact lithium-ion battery.
This contributes to 36.2mpg on the tougher new WLTP cycle, 164g/km CO2, and – claims Audi – the ability to run for over 620 miles between pit stops. If there were still an Audi Le Mans programme, the marketing synergies would be simply incredible. Alas, ironically, dieselgate.
But an electrically powered compressor (EPC) is new to the S6, just like the one on the V8 turbodiesel SQ7 SUV. It adds only 3.5kg or so, and is said to spool up instantly at low revs. With lag no longer such an issue, the EPC has liberated Audi engineers to fit a larger turbocharger, adding extra muscle in the mid-range. And there is quite a lot of the stuff, 516lb ft from 2500rpm to be precise.
That’s much more than the previous petrol’s 406lb ft. Power rises from the 50TDI’s 282bhp, to a hugely impressive 344bhp – though no doubt some buyers will be incredulous that the old petrol S6 put out 444bhp. It is a tricky message to get across.
An eight-speed Tiptronic auto is standard, so too Quattro all-wheel drive. But you can also option rear-wheel steering, carbon-ceramic brakes, air suspension, Dynamic steering and a sport differential.
Does turbodiesel power really suit the S6?
Fundamentally, yes. Despite the EPC, there is still a little lag when you squeeze the throttle, and you might find the power delivery a little flat in the higher revs – it is, after all, a compression ignition engine, they all do that, sir. But keep it between 2000rpm and 3500rpm and the mid-range punch is properly thumping.
It sounds and is a narrow little window of fun, but the eight-speed auto helps you land back in the powerband gear after gear. It’s like being boosted into the air by a mate on a trampoline, a huge surge of energy, especially in second, third and fourth (though shifting manually via paddleshifters is more effective than the not always spot on auto mode).
It’s smooth and sounds good too, with a deep rumble under acceleration that’s just the right side of subtle. Factor in high levels of refinement, a pretty lavish interior and plenty of space and that long touring range and you’ve got a highly compelling package.
This sounds too good to be true. When do we get to the ‘cold’, ‘surgical’ and ‘understeery’ Audi bit?
We don’t, because the S6 handles very well indeed. It’s secure and sure-footed as you’d expect, but it also feels highly rear biased and engaging. It grips hard at the front, body roll is nicely gathered up, and the nimble feel makes you double take when you see the – yikes – two-tonne kerbweight.
There are caveats, however – all our test cars got the optional rear-wheel steering and sport differential. The rear-wheel steering does the usual trick of turning the rears in the opposite direction to the fronts at lower speeds, where you really can feel it adding to the responsive feel. The rears then turn in the same direction for better stability, as per. And maybe the sport differential is particularly transformative in making the S6 feels so rear-biased and dynamic if you’re really aggressive through turns.
Did you try any other options?
Yes. The air suspension felt much floatier in its Comfort setting, but still very firm in Dynamic. Perhaps air will come into its own in the UK, but on the basis of this test drive, standard coils and dampers felt the better choice, even on 21-inch alloys (20s are standard).
Barely anyone will spec the carbon-ceramic brakes, but we tried the S7 (basically an S6 with a four-door ‘coupe’ body) with them and its point-to-point capability became almost daft, with a wafer-thin margin between going far too fast and coming to a complete stop – though the feel and stopping power mean I’d certainly have them if I could, and you don’t have to drive like a lunatic if you get them. It’s just that you can.
None of the cars we tried were fitted with Dynamic steering, so we can’t provide a definitive verdict. The standard set-up felt perfectly decent, though, ticking off the ‘quick, precise, if lacking in outright feel’ checklist.
New Audi S6: verdict
As a sports saloon to cover all the bases, the Audi S6 has quite the skillset. It’s refined, luxurious and long-legged at a cruise, but rich mid-range torque and a rear-biased if secure chassis make it highly engaging point-to-point. Certainly, the RS6 will amp up the thrills, but the S6 now takes its own path, and it’s turbodiesel power that makes this cheaper, more frugal model such a compelling alternative. You can nit-pick, but to hell with it, I like this S6, and I think for what the average sports saloon buyer actually needs in daily use it’s bang on. Five stars.