Audi could, were it so inclined, build a saloon every bit as appealing from behind the wheel as a BMW 5 Series, but it chooses to fight on a different front and spend its development budget elsewhere. As ever with the A6, a large part of that ‘elsewhere’ is rolling refinement.
Worrying, then, that tranquillity isn’t a given. The bulk of entry-level 40 TDI cars (note, these are only available in front-wheel-drive configuration) will use the passive suspension setup that’s standard on both Sport and S Line models. In the interests of body control and – we shouldn’t pretend otherwise – kerbside stance, on S Line versions the steel springs are 20mm shorter. We briefly tried such a car and while the resulting ride is nicely taut, on British roads it was also too busy, too much of the time for a limousine of this ilk.
You can add some adaptive functionality to the dampers for an extra £1150 – we haven’t tested these yet, though it’s likely the Comfort setting would improve matters – but the majority of 50 TDI models will be ordered with £2050 adaptive air suspension.
It’s an expensive option but with it this quattro chassis better mops up everything from the perma-jostle of corrugated B-roads to the gentler, low-frequency motorway undulations. Severe impacts from potholes and the like can announce themselves with something of a 'thwack' and the pneumatic springs further numb the driver from what’s happening down at road level, but the spacecraft glide big Audis are known for is present and correct.
In fact the A6 rides beautifully on its air springs, softly bracing the body over peaks, through troughs and resisting well the sort of pitch and roll movements that can easily overwhelm a 1900kg saloon.
Less convincing is the £1950 Dynamic all-wheel steering, which undoubtedly gives a very large car surprisingly agility through slower, tighter bends but to such an extent that it can feel quite unnatural. City-dwellers will like it but we would happily do without the need wind off lock unexpectedly. Moreover, it does nothing to enliven the driving experience.
You might put the money ‘saved’ towards having the V6 TDI in the car’s engine bay, as opposed to its smaller, more ordinary four-cylinder sibling.
This unit’s turbochargers abruptly awaken just shy of 2000rpm, but from thereon until the far side of 4000rpm there’s effortless motive force thanks to peak outputs of 457lb ft, which is nothing short of vast, and a healthy 282bhp. It’s enough to haul the 50 TDI chassis – longer, wider and taller than before – to 62mph in 5.5sec. That’s significantly quicker than the 8.1sec of the 40 TDI but a shade slower than rivals from BMW and Mercedes. On the move, speed nevertheless accrues at an alarming rate, and in subversive fashion.
But performance is only a small part of it. The larger Audi engine is tremendously well mannered, remaining almost inaudible at a cruise, though it wouldn’t offend the ears even were it not. Meanwhile the eight-speed automatic transmission is slick most of the time but can occasionally hiccup at town speeds. On open roads there’s barely a break in the flow.