Audi S8 review
The Audi S8 is the performance flagship version of the classy, understated and hi-tech A8 executive saloon
The Audi S8 is a bonkers executive limo with increbile pace and scarcely believable traction. It's based on the standard A8 and sits at the top of the Audi model range – above the A4 and A6 saloons. It remains a niche option, but for some it's the ultimate example of understated wealth.
A Mercedes S-Class is a more modern, better resolved car, while the BMW 7 Series is arguably more fun to drive. That said, the Audi's twin-turbo V8 is a gem, making it hard to ignore the S8's brutish, muscle car charm.
Like all other Audi S and RS models, the S8 represents the fastest and most exclusive version available. Using the standard A8 saloon as its base, the S8 adds a twin-turbocharged V8 engine with more than 500bhp, as well as aggressive styling tweaks to the exterior and interior. Those wanting even more performance can opt for the 'Plus' version, sending power rocketing to almost 600bhp.
Unlike many of its rivals from Mercedes, BMW and Jaguar, the all S8s feature quattro four-wheel drive to help cope with the added power – and as a result it also provides superb grip even in wet and wintry conditions.
Despite the muscular performance, the S8 is still a quiet and comfortable limousine, with a luxurious and stylish cabin. However, while it is incredibly capable, all models are expensive and lack the engaging dynamics of its rear-wheel-drive rivals.
Engines, performance and drive
The Audi S8 feels much like an old-school muscle car. The V8 engine is a brute, and the four-wheel drive powertrain ensures limitless traction in any weather.
It doesn't offer the last word in driver involvement – you'll need to look to the Mercedes S-Class or BMW 7 Series for that – but there's still plenty of feedback through the wheel, giving you confidence in any situation. It's nicely refined too – as you'd expect from a luxury limousine – making high speed motorway driving a doddle. The gearbox is slick and easy to use, especially if you leave it to its own devices. In fact, despite having more power than five Ford Fiestas, the S8 is incredibly straightforward to drive.
There are two cars to choose from; the standard 513bhp S8, and the bonkers 597bhp S8 Plus. To be honest, the lesser car will suffice for most, but the lure of a two-tonne saloon car with 600bhp is hard to ignore.
Although the Audi S8 uses the same 4.0-litre twin-turbo V8 as the lesser S6 and S7 models, the engine's power output has been increased to an incredible 513bhp and 650Nm of torque. This makes it blisteringly quick in a straight line, but thanks to the standard-fit quattro four-wheel drive system and adjustable air suspension, it also offers up plenty of grip in the corners.
That said, there's no escaping the fact that this a two-tonne car and at times it feels like too much weight for the brakes and steering to cope with. Plus, as the S8 comes with a very clever active noise cancellation system that makes it virtually silent at cruising speed, it means the S8 isn't as engaging as an AMG-badged Mercedes S-Class and its not as comfortable either.
Those wanting even more from their executive Audi, can opt for the bonkers S8 Plus version. It uses an uprated version of the standard car's twin-turbo V8 engine – producing a scarcely believable 597bhp and 750Nm of torque. It'll do 0-62mph in just 3.8 seconds and hit 189mph with the Dynamic Package fitted. That makes it faster than an entry-level Porsche 911.
MPG, CO2 and running costs
Running a powerful and expensive car like the S8 will require very deep pockets. Although the new twin-turbo V8 engine does use cylinder-deactivation technology to maximise efficiency, drive it hard and the S8 will struggle to return more than 20mpg (despite Audi claiming 30.1mpg), while CO2 emissions of 216g/km put it in one of the top brackets for road tax. The higher-powered S8 Plus is even thirstier, returning even fewer miles per gallon and 231g/km of CO2.
Other consumables like tyres and brakes will also need replacing more regularly than with the standard A8 and repairs at an Audi approved dealer will be very costly.
As you'd expect, both the S8 and S8 Plus fall into the top group for insurance, meaning no matter which model you go for, you'll be forced to pay big premiums. That's no different to its biggest rivals though, so the Audi's slightly cheaper list price may be enough to seal the deal for potential customers.
Big luxury saloons also struggle to hold onto their value so despite its premium image, the S8 will drop considerably in value after only a few thousand miles. Official figures say the S8 will retain between 30 and 35 per cent of its value after three years, meaning big drops if you buy new. For comparison, a Mercedes AMG-S63 will keep up to 46 per cent of its value, making it a better bet long-term.
Interior, design and technology
The standard A8 has often been criticised for its bland styling but the S8 helps to address this problem by adding enormous 20-inch alloy wheels, a more aggressive single-frame chrome grille and a subtle body kit. At the back, a set of quad-exhaust pipes and special 'S' badging are the only clues to its performance potential. A facelift late in 2013 sharpened up the bumpers and added a new set of headlights.
The S8 Plus is distinguishable by its high-gloss detailing and darkened rear light clusters but is otherwise identical to its lesser-powered sibling.
Standard equipment across the S8 range is very generous, too, with hi-tech kit like sat-nav, BOSE surround sound and climate control all fitted as standard. However even with these tweaks, the A8 fails to standout like the Jaguar XJ Supersports or even its smaller and cheaper sibling, the Audi S7 Sportback.
Sat-nav, stereo and infotainment
On the inside, the A8's already high-class interior has been given a range of sporty upgrades, including grey-back dials, carbon-fibre trim and quilted leather and Alcantara on the seats and dashboard. Unfortunately, the S8 misses out on the TT, A4 and R8's brilliant Virtual Cockpit display, feeling a little dated as a result. But that's not to say it's an unpleasant place to be – it's still a high quality design that feels only marginally less special than its key rivals.
Practicality, comfort and boot space
The S8 offers the same generous level of space as the standard A8, which means a 520-litre boot. It also comes with an electric tailgate and an opening that's wide and flat, making it easy to load even the bulkiest of items. Rear seat passengers are well catered for, too, with enough head and legroom for three adults in the back and plenty of handy cubby holes.
Up front, there's a huge range of adjustment for both driver and passenger and despite its dimensions, visibility is good so the S8 is fairly easy to park. It also features a massive 90-litre fuel tank to help improve its cruising range on the motorway.
The S8 is only available as a standard wheelbase car, with no S8 L option. Compared to its two biggest rivals – the Mercedes S-Class and BMW 7 Series – the S8 is both the longest and the heaviest. At more than five metres long, it's not a small car, while at almost two tonnes, it's 130kg more than the latest BMW limo.
Leg room, head room & passenger space
Despite the S8 only being available as a short-wheelbase car, there's plenty of room in the back to stretch out. Based on the standard A8, it sits above the A4 and A6 in Audi's extensive model range. There's decent head room and legroom will be more than sufficient for all but those with the longest limbs.
The S8 pips its main rivals for outright bootspace. With a well-shaped 520-litre load area, there's five litres less in a BMW 7 Series and 10 litres fewer in a Mercedes S-Class. That means there's more than enough room for a few suitcases (essential for all those airport business trips), while an electric tailgate means you needn't get your hands mucky either.
Reliability and Safety
While the S8 uses a new engine, the gearbox and four-wheel-drive system are both used in the standard car – so should prove dependable in the long term. There's a wide variety of complicated electronics on board, too, but Audi has a well-earned reputation for reliability that rivals like Jaguar can't really compete with.
That said, despite this strong tradition the brand only returns average scores in the annual Driver Power survey and finished 13th – behind Mercedes but ahead of BMW in the overall standings in 2015. Safety should not be a concern in the S8, though, as its aluminium space frame chassis is very strong and technology, like two-stage traction control and a pre-sense system that prepares the car for a collision by tightening the seat belts and closing the windows, are included as standard. Options like a night-vision camera and radar-guided cruise control are also available.
The Audi S8 boasts the same comprehensive warranty as the rest of the product range, meaning you get the same three-year/60,000-mile guarantee as you would on an A1 supermini. You can extend this to four years/75,000 miles for £1,035 or five years/90,000 miles for £2,555. You'll need deep pockets to run an S8, with those warranty costs identical to that of the R8 supercar.
Audi’s fixed-price servicing makes it easy to budget for maintenance. Buyers pay around £350 to cover dealer servicing of A8 and S8 models for the first three years, which isn't actually too bad. Of course, you'll pay more for tyres and other consumables due to the power and ferocity of the V8 engine.