Like the standard A8 on which it based, the S8 is constructed almost entirely from aluminum, helping to keep performance- and efficiency-sapping weight down to a minimum. The two are also closely related outside, with a handful of touches like a sportier front fasica, unique grille, rear diffuser and 21-inch wheels setting the S8 apart.
Audi pared down the line-up to just the range-topping plus model for the latest model year. Under its long hood lies a 4.0-liter V8 that more than makes up for its relative lack of displacement with a pair of turbochargers and direct injection. Output is quoted at 605 horsepower and 517 lb-ft of torque from 1,750 to 6,000, although both figures are likely conservative. In independent testing, the S8 has sprinted from zero-to-60 mph in just 3.5 seconds, suggesting the sedan may be packing more ponies than advertised.
Power is sent to all four wheels via an eight-speed with paddle shifters and Audi's quattro all-wheel-drive system, which in this application features a 40:60 front/rear torque split. A standard rear torque vectoring system can send power to the outside wheel to minimize understeer or oversteer in turns.
The yin to the V8's yang are powerful brakes with massive rotors that measure 15.75 inches in the front and 14.37 inches in the rear. Lightweight carbon ceramic brakes are available for even more extreme stopping power.
The S8 rides on a full air suspension with adaptive dampers, and the setup can be adjusted to suit the driver's preferences with a Drive Select system that also controls throttle response, steering effort and shift calibration.
With Drive Select in its sportiest setting, the S8 is remarkably agile for such a large machine, with precise steering and well-controlled body motions. Toggle the system into comfort mode, and the S8 adopts the roll of the pampering luxury sedan, with softer, more deliberate responses and a relaxed ride.
Despite its performance credentials, the S8 is no gas guzzler - it's rated at 14/24 mpg - due to a cylinder deactivation system that essentially turns the engine into a V4 in low-throttle highway driving. Known as Cylinder-on-Demand, the setup employs active noise cancellation technology and active engine mounts to eliminate any NVH issues that would be uncouth in such a premium vehicle.
The Inside Story
Impeccable craftsmanship and an elegant design define the cabin, which features rich details like quilted leather, real metal trim and the buyer's choice of wood or carbon fiber accents. Well-bolstered sports seats keep the driver and front passenger in place during spirited driving, while a three-spoke steering wheel and aluminum pedals are model-specific touches.
There's plenty of room for five to sit in perfect comfort, and a plethora of optional luxuries make the cabin experience truly first class: heated, ventilated and massaging front and rear seats, four-zone automatic climate control, a rear seat entertainment system with dual 10-inch screens, and an incredible 19-speaker, 1,200 watt Bang & Olufsen sound system with speakers that rise from the dashboard upon startup in a neat piece of theater.
Navigation and entertainment functions are accessed through Audi's MMI system, which includes a novel touchpad for entering destinations or other info by writing out numbers and letters with a finger. It's one of the more intuitive infotainment setups on the market, although some users find that its location at the base of the center console requires a bit of a reach.
The navigation system incorporates Audi Connect with in-car internet connectivity and industry-first Google Earth integration that provides panoramic views and high-resolution 3D satellite/aerial imagery.
Standard and Optional Features
The S8 comes well-equipped with quilted leather upholstery, heated and 22-way power-adjustable front seats, a navigation system with SiriusXM Traffic, a 14-speaker, 630-watt Bose AM/FM/CD/SiriusXM/HD Radio Surround Sound System, Bluetooth connectivity, front and rear parking sensors, a 360-degree bird's-eye view camera system, a rear parking camera, a sunroof, power rear/rear side sunshades, four-zone automatic climate control, LED taillights, full LED headlights, and 21-inch alloy wheels.
Several different options packages are available.
The Driver Assistance Package brings adaptive cruise control, Audi pre-sense plus (full description in safety section), Audi side assist and lane assist, and auto-dimming high beams.
The Cold Weather Package includes a heated steering wheel, heated rear seats and a rear seat pass-through with ski bag.
The Audi Design Selection Package adds heated rear seats, balsamic brown natural fine grain ash wood inlays, alcantara headliner, valcona leather seats with sport stitched-diamond look and comfort front seats.
Standalone options include Night Vision Assistant with Pedestrian Detection and Animal Detection (the latter is new for the latest model year), a Bang & Olufsen sound system and a rear entertainment system. A head-up display is also newly available, as is a Vermont Brown leather with twill copper inlays.
All S8 models come standard with dual front, front knee, front side, rear side and full-length side curtain airbags in addition to traction and stability control systems.
Optional safety features include active lane assist, which warns the driver when the S8 is wandering into an adjacent lane and can even gently steer the car back into the original lane. There's also Audi pre sense, which can detect obstacles in front of the S8 and apply the brakes to prevent a crash or mitigate its severity. Finally, Audi side assist alerts the driver when a vehicle is in one of the S8 rear blind spots.
The closest competitor to the S8 is the Mercedes-AMG S63, which provides a similar mix of luxury and performance. The V12-powered BMW M760i serve up comparable power in a package that's just as luxurious.