Believe it or not, at between 4,400 and 4,800 pounds, the Audi A8 is one of the lightest large luxury sedans. It's built on an aluminum space frame, and that defining feature, along with some carefully done electronic controls, help it drive like an even smaller, lighter sedan.
This year, a set of new powertrains ratchets performance up and betters gas mileage. In the order of number of cylinders and output, the engines now rank from a supercharged six, to a pair of twin-turbo V-8s, to the carryover W-12. Each has a distinct mission in mind, and we have our favorites, for sure.
The 3.0T gives Audi more reach at the bottom end of the A8 lineup. It gets its power from a 3.0-liter six-cylinder with supercharging that next out at 333 horsepower and 325 pound-feet of torque. As the entry-level replacement engine for the former 4.2-liter V-8, it's a flexible powerplant with more muted response than we've heard from it in other Audis--and it's still capable of 0-60 mph times estimated at 5.5 seconds, and a top speed of 130 mph. Respectable numbers at a respectable price point, all things considered.
Smoother, and pulsing with an altogether more visceral brand of power, Audi's new 4.0-liter twin-turbo V-8 hits the sweet spot. In standard issue, it has 420 hp and 444 lb-ft of torque, and slices 0-60 mph times to 4.7 seconds. Which is fine until you consider the same engine in a more advanced state of tune turns in 520 hp in the Audi S8, and delivers 60 mph in 3.9 seconds along with a top speed of 155 mph. The former comes in either body style, the latter only as a short-wheelbase sedan. No matter which you choose, disappointment isn't an option.
The much more exclusive W12 packs a 6.3-liter, twelve-cylinder engine into the long-wheelbase A8. It turns in 500 hp and 488 lb-ft of torque, and is capable of getting to 60 mph in an estimated 4.4 seconds on its way to 130 mph. We've spent the least time with this powertrain, but have driven related iterations of it extensively in other sedans and coupes. We'd predict its appeal goes deeper than the 12-cylinder badges, but we'd probably cut that corner if it were our own portfolio.
No matter the power source, every A8 shares the same eight-speed automatic--and Audi simply nailed its calibration. It always seems to grab the right gear quickly, and simply, and smoothly. It's also one of the reasons the A8 scores such impressive fuel economy numbers (up to 29 mpg highway with the 3.0T). If you're in its Comfort or Auto modes, the transmission shifts early; if you press intently, it's happy to fire off multiple downshifts before you can click the steering-wheel-mounted shift paddles. Even in the six-cylinder long-wheelbase models, an eighth-to-third downshift brings about a rush of meaty passing power.
Quattro all-wheel drive delivers sure-footed feel to the A8, even though the complexity of its suspension and wheel-and-tire offerings require a patient hand and Microsoft Excel license. (It's a German thing.) Quattro splits torque front to rear at a 40:60 ratio from takeoff, shifting power to a maximum of 60 percent front if the myriad sensors determine it need be so. On the S8, an active torque split from side to side comes into effect with the sport differential; it's now an option on other models as part of a Sport plus package, along with dynamic steering, adaptive air suspension, and summer 265/40 tires.
And therein lies the complexity. It's possible to configure an A8 3.0T with 19-inch all-season tires, or to opt an A8 L W12 up to Sport plus with summer tires, or to crank up the S8 to 21-inchers. The spectrum is broader than you think, particularly with Audi's Drive Select system on tap.
Drive Select is the electronic godhead that controls the A8's powertrain responses, steering weight, and suspension feel. It's set up with Comfort, Auto, Dynamic, and Individual modes, the last one of which can be programmed by the driver. It's a system that's gotten better in its current iteration, as Audi's switched over to electric power steering; the rack itself doesn't have much feel, but the disparate sensations across the systems in older Audis has been overcome, and Drive Select gives a more coordinated set of responses between throttle, ride, and shifts.
Maybe there's a little too much heft dialed into Dynamic mode, but that choice exists for the few enthusiasts who'd choose this model over an A7. But in all, the A8 is nicely tuned. There's barely any lift under hard acceleration or nosedive under hard braking—adding to the sophisticated, composed feel of the A8.
Of course, you can play tantric games with Drive Select too--put the S8 into Efficiency mode, or dial the W12 into Dynamic--but like real tantric moves, it's more enjoyable in theory.
The high-water mark of the group is set by the S8, of course. It's not a pure athlete, not at 4,500 pounds, but compared to some of its rivals, it feels like a sprinter. It's still blessed with enough body lean and ride compliance to feel less like an outlier in the A8 family--but also, to feel completely natural charging out of an exit ramp at triple-digit speeds, utterly composed thanks to variable-ratio steering and outstanding brakes.