Audi S8

At this rarefied end of the luxury saloon market it’s all about maximum speed with the minimum of fuss – and in this respect the S8 leads the pack. Driving it flat-out might not be as rewarding as the S63 AMG or the Jaguar XJ, but it’s cheaper, more efficient, and in a drag race from 0-62mph it will leave both of them, and the new BMW M5, trailing in its wake. Audi has stuck to it formula with the new S8, but thanks to a groundbreaking new engine and a highly competitive price its more appealing than ever.

The Audi S8 has always represented the pinnacle of its S family, and this third-generation model is no different. It marks the debut of an all-new, 4.0-litre twin-turbo V8, which replaces the old 5.2-litre V10, and catapults it to the head of the class in terms of speed and efficiency.

Its rivals might have the edge in certain areas; the Mercedes S63 AMG has 24bhp more power and the Jaguar XJ Supersport is 83kg lighter, but neither can touch the S8’s 0-62mph time of 4.2 seconds, CO2 emissions of 237g/km or fuel economy of 27.7mpg – an 84g/km and 6.3mpg improvement over its predecessor despite a power increase of 69bhp.

This new V8 is a remarkable piece of engineering. As well as stop-start, it has the ability to shut down four of its eight cylinders at speeds above 15mph, so long as the engine is rotating between 930 and 3,500rpm, and the selected gear is third or above. Audi claims it can save up to 12 per cent fuel consumption when cruising at 50mph.

A notification is displayed when four-cylinder mode is activated – but that’s the only way you would know. The change over is seamless, and there's no drop in acceleration or judders from the engine bay.

This is helped by an active noise cancellation system, which samples the clatter in the cabin via four tiny microphones, and counters intrusive sounds by pumping opposite waves through the speakers. It not only cancels out unwanted engine hiccups either – it means tyre roar and wind noise are suppressed too, creating an eerily quiet cabin at motorway speeds.

Despite downsizing from a V10 to a turbo V8, the S8 has lost none of its potency. The maximum torque is spread right from 1,700rpm to 5,500rpm, so regardless of gear, it surges forward like a sports car. There’s no hint of turbo lag either – just instant, ferocious acceleration, helped by the four-wheel drive.

A daunting array of settings are available for customising the chassis. Five parameters can be contolled – the lowered sports air suspension, variable ratio steering, throttle mapping, gearbox and sport differential – with five separate settings for each. Go for the optional carbon-ceramic brakes, and the S8’s spec sheet could be mistaken for a supercar. It’s only right then that we put it through it paces on track.

With everything cranked to its most dynamic setting, body roll is minimal and the steering is sharp and accurate. Exiting a corner the grip is phenomenal, but carry any sort of speed into one and the nose washes wide with understeer. On the road the big Audi’s pace, poise and ride quality is exceptional, but on the track it’s outshone by the Mercedes S63 AMG, CLS63 AMG and Jaguar XJ Supersport.

As for the looks, big saloons don’t come any more understated than the A8. The S8 ups the trinket count with 20-inch wheels as standard (the 21-inch alloys on our test car are an option), a subtle bodykit and chrome bars in the grille. Inside, the new sport seats provide just enough support while the quality of materials and craftsmanship throughout is faultless.