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In-depth reviews

Audi A8 review - Engines, performance and drive

Ride quality niggles remain, but the A8 has been built with an autonomous future in mind

It’s not often we’d say that the driving experience is of secondary importance to the comfort of the rear seat passengers, but in the case of the A8 we’d make an exception. That’s not to say that driving an A8 is disappointing – far from it, because there’s a certain amount of pleasure associated with lording it about in the flagship Audi. 

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The fourth generation car is 95kg heavier than before, but performance remains strong, with the petrol version accelerating to 62mph in 5.6 seconds and the diesel in 5.9 seconds. Opt for the long-wheelbase A8 L and the sprint time increases to 5.7 seconds in the petrol. There’s no penalty for diesel drivers, though. Top speed is limited to 155mph. 

As you’d expect, both versions are incredibly refined, developing little more than a muffled growl under load, before becoming almost inaudible at cruise. The A8 now features a 48-volt mild hybrid system, which enables the car to coast with the engine switched off, before seamlessly restarting when required. It makes for an even smoother experience on those long cross-continent business trips. 

That’s not to say the A8 feels cumbersome and oversized when you turn off the motorway. Thanks to four-wheel steering, which turns the rear wheels in the opposite direction to the fronts at lower speeds, the A8 feels like the smaller A4 saloon around town. 

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The sheer weight and width of the A8 are never far from your mind, but the brakes are more than up for the task of bringing this behemoth to a stop. The one area where it does fall behind the S-Class is ride quality, but with the firmness comes improved body control.

Of course, the fourth-generation A8 has been built with an autonomous future in mind, but we’ll have to wait before testing this functionality. Traffic jam pilot – which takes charge of driving in slow moving traffic up to speeds of 37mph – will be rolled out at a later date, along with parking and garage pilot systems. 

Engines

The 3.0-litre V6 diesel – badged as the 50 TDI – is likely to be the best-selling A8 in the UK. It delivers 282bhp and 600Nm of torque to deliver a 0-62mph time of 5.9 seconds and top speed of 155mph. 

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The 3.0-litre V6 petrol – badged as the 55 TFSI – delivers 335bhp and 500Nm of torque to deliver a 0-62mph time of 5.6 seconds (5.7 seconds in the long-wheelbase version) and a top speed of 155mph. 

Both engines feature a 48-volt mild hybrid system, which enables the A8 to coast with the engine switched off when cruising. It also has an extended start-stop system and an energy recovery system. Audi claims that the combined effect improves fuel economy by 0.7-litres for every 62 miles (100km) driven. That doesn't sound like much, but those savings will build up over time.

The 55 TFSI doesn't feel quite as brisk as the 50 TDI due to its torque defecit, but it's plenty fast enough and accelerates with linear smoothness. It's also so quiet as to be almost silent at idle, and supremely hushed at motorways speeds.

Opting for smaller alloys than the 20-inch wheels we've tried on a 55 TFSI might be best, though; the ride, while by no means uncomfortable, could be made more in keeping with the A8's big-exec status if 19, or even 18-inch alloys were fitted.

Other engines will be rolled out over time, with Audi promising a 4.0-litre V8 diesel, an A8 L e-tron plug-in hybrid and a flagship W12.

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Which Is Best

Cheapest

  • Name
    S8 Quattro Vorsprung 4dr Tiptronic
  • Gearbox type
    Semi-auto
  • Price
    £0

Most Economical

  • Name
    60 TFSI e Quattro Vorsprung 4dr Tiptronic
  • Gearbox type
    Semi-auto
  • Price
    £0

Fastest

  • Name
    S8 Quattro Vorsprung 4dr Tiptronic
  • Gearbox type
    Semi-auto
  • Price
    £0
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