Limo or sports saloon? The idea behind Audi’s S8 is that you can have both in the same package, and it’s an experience delivered with varying degrees of success over the years.
On the one side are the physical laws of the universe, doing their best to ensure a vehicle so large and heavy cannot possibly deliver the characteristics we look for in a driver’s car. On the other, the minds of deeply intelligent engineers applying technology to try to overcome those physical constraints. How close does the latest S8 come to mixing the demands of both?
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Engine, transmission and 0-60 time
While other S-badged Audis have recently gone diesel, the S8 remains petrol-powered in this generation, using the same 4-litre twin-turbocharged engine we’ve seen recently in the RS7.
In this application it develops 563bhp (50bhp more than in the old S8) and 590lb ft of torque, a 111lb ft improvement. The sole transmission is an eight-speed Tiptronic automatic, naturally connected to a quattro-branded all-wheel-drive system. A limited-slip ‘sport’ differential at the rear axle is standard, as is 48V mild-hybrid technology, more accurately described as a belt-driven starter-alternator to selectively reduce load on the drivetrain with the aim of saving fuel.
The upshot of the power and torque increases is a 0-62mph time of 3.9sec (two-tenths quicker than before), while top speed is limited to the same 155mph.
The S8’s killer app is its predictive adaptive suspension. Using the air suspension that A8s are already fitted with, it uses actuators at each wheel to individually adjust the ride height to deal with bumps, reading the road ahead with a camera system.
The technology used by the predictive suspension also confers other benefits. One is the ability to raise the car by 50mm when you open the door (from inside the car or out of it) to make stepping in and out more comfortable. Another is the ability, in Comfort+ mode, to tilt the car up to three degrees into a corner to minimise the effects of lateral force on the passengers.
Aside from the fancier features, the S8 has some Audi staples: four-wheel steering, variable torque distribution for the all-wheel drive (up to 70 per cent to the front axle and up to 85 per cent to the rear), and a sport differential at the rear axle.
What’s it like to drive?
If the S8 has driver appeal, it takes some digging to reach, but technophiles will instantly warm to the S8 on account of that deeply clever suspension.
Cars that lean into corners, rather than rolling in the direction of the forces acting upon them, are still few and far between, so it’s a unique and strangely compelling sensation when the S8 gently sits down into each turn.
Even more remarkable is the way the car quickly raises before a speed bump, and then floats over it, staying perfectly level and transmitting almost none of the vertical energy into the cabin. The only car I’ve experienced that behaves anything like it is a Citroën CX, and while that Citroën takes the sting out of smaller road imperfections even better than the Audi, it’s fair to say it can’t match the S8’s body control elsewhere, either.
It’s not infallible; sharper intrusions still find their way into the cabin, and the system relies on having a decent view ahead to prepare itself for bumps, so anyone adopting the stereotypical Audi attitude towards personal space will find themselves bouncing over bumps with the rest of the traffic.
And naturally, the S8 does the limousine thing elsewhere too. Wind noise is reduced to a gentle rustle at speed, tyre noise is low, and the V8 hums quietly away in the background until you rouse it. It has easy steering, good directional stability and, thanks to the four-wheel steering, is surprisingly easy to manoeuvre.
So is it also a sports saloon? Well, to a degree, yes. That four-wheel steering, just as it does on the A6/S6 and A7/S7 (plus other large Volkswagen group vehicles such as the Bentley Bentayga and Porsche Cayenne), gives the S8 uncanny agility for a vehicle so large and heavy.
Turn-in is swift, and at the point you’re certain the S8 will begin to wash wide, it seems to find an extra few degrees of yaw to neutralise any understeer and scoot through undramatically. Feed in the power and the S8 will continue to hold its line and gallop down the next straight with similarly little effort and a background rumble from the V8.
The luxo-barge origins show through in steering that’s fairly light off centre and weights up only gently in cornering, as well as in the delay to each request for a downshift and the fairly soft brake pedal. It is, ultimately, closer to a limo at heart than it is a sports saloon – but when the roads get twisty it’ll still do a pretty convincing impression.
Price and rivals
Both, as you’ll note from their respective branding, are all-wheel drive like the Audi, but while the AMG has a matching four-litre V8, BMW offers a 6.6-litre V12. Despite the extra capacity, it’s the AMG that produces the most power (604bhp, to the BMW’s 577 and the S8’s 563), and the AMG is also torquiest with 664lb ft, followed by the 627lb ft BMW and 590lb ft Audi. Oddly, despite being the lightest at 1970kg (2230 for the Audi, 2220 for the BMW) the Mercedes is slowest off the line at 4.3sec to 62mph, to the S8’s 3.9 and the BMW’s 3.8.
Numbers only tell some of the story, of course. All three are outstandingly capable given their size and weight, yet all three also come closer to the limousine brief than they do sports saloons. As a result, we’d be inclined to choose the best limo. That, as it so often has been over the years, is the Mercedes. And if you want a proper supersaloon, you need to sacrifice some luxury and look at the RS7s, M5s and E63s slightly further down the range.