Audi A6 50 TDI S Line 2018 UK first drive

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.

Except when you’re in the car’s most economical mode, that is, when there is a very definite break in the flow. This is because the 48-volt system allows the engine to shut down completely if it’s not needed for a several moments, and then reignite when the throttle is depressed. It’s a nicely calibrated process that doesn’t frustrate, and helped our test car achieve a touring economy approaching 50mpg.