2019 Mercedes S-Class vs. 2019 Audi A8

Detailed Review, Specifications & Comparison

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Safety

The rear seatbelts optional on the S-Class inflate when a collision is detected, helping to spread crash forces over a much larger area of the body and limiting head and neck movement. This can help prevent spinal and internal injuries. The A8 doesn’t offer inflatable seatbelts.

The S-Class’ driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The A8 doesn’t offer a driver alert monitor.

The S-Class has standard Mercedes-Benz Emergency Call, which uses a global positioning satellite (GPS) receiver and a cellular system to remotely unlock your doors if you lock your keys in, help track down your vehicle if it’s stolen or send emergency personnel to the scene if any airbags deploy. The A8 doesn’t offer a GPS response system, only a navigation computer with no live response for emergencies, so if you’re involved in an accident and you’re incapacitated help may not come as quickly.

Both the S-Class and the A8 have standard driver and passenger frontal airbags, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available all wheel drive, night vision systems, around view monitors and rear cross-path warning.

Warranty

There are over 26 percent more Mercedes dealers than there are Audi dealers, which makes it easier should you ever need service under the S-Class’ warranty.

Reliability

J.D. Power and Associates rated the S-Class third among large premium cars in their 2018 Initial Quality Study. The A8 isn’t in the top three in its category.

J.D. Power and Associates’ 2018 Initial Quality Study of new car owners surveyed provide the statistics that show that Mercedes vehicles are better in initial quality than Audi vehicles. J.D. Power ranks Mercedes 14th in initial quality, above the industry average. With 13 more problems per 100 vehicles, Audi is ranked 25th, below the industry average.

Engine

The S 450’s standard 3.0 turbo V6 produces 27 more horsepower (362 vs. 335) than the A8’s 3.0 turbo V6 hybrid. The S 560’s standard 4.0 turbo V8 produces 128 more horsepower (463 vs. 335) and 147 lbs.-ft. more torque (516 vs. 369) than the A8’s 3.0 turbo V6 hybrid. The AMG S 63’s standard 4.0 turbo V8 produces 268 more horsepower (603 vs. 335) and 295 lbs.-ft. more torque (664 vs. 369) than the A8’s 3.0 turbo V6 hybrid. The AMG S 65/Maybach S 650’s standard 6.0 turbo V12 produces 286 more horsepower (621 vs. 335) and 369 lbs.-ft. more torque (738 vs. 369) than the A8’s 3.0 turbo V6 hybrid.

Fuel Economy and Range

An engine control system that can shut down half of the engine’s cylinders helps improve the S-Class 560/63’s fuel efficiency. The A8 doesn’t offer a system that can shut down part of the engine.

The S-Class V12’s standard fuel tank has 2.9 gallons more fuel capacity than the A8 (24.6 vs. 21.7 gallons).

Transmission

A nine-speed automatic is available on the Mercedes S-Class, for better acceleration and lower engine speed on the highway. Only an eight-speed automatic is available for the A8.

The S-Class 63/65’s launch control uses engine electronics to hold engine RPM’s precisely in order to provide the most stable and rapid acceleration possible, using all of the available traction. The A8 doesn’t offer launch control.

Brakes and Stopping

For better stopping power the S 63/65’s brake rotors are larger than those on the A8:

 

S 63/65

A8

Front Rotors

16.5 inches

14.8 inches

Rear Rotors

14.2 inches

13.8 inches

The S-Class S 63/65 offers optional heat-treated ceramic brake rotors, which last ten to twenty times as long as conventional cast iron rotors, don’t rust, don’t fade during repeated high speed braking, and their lighter weight contribute to better braking, handling and acceleration. The A8 doesn’t offer ceramic brake rotors.

Tires and Wheels

The S 63’s 255/40R20 front and 285/35R20 rear tires provide better handling because they have a lower 40 series front and 35 series rear profile (height to width ratio) that provides a stiffer sidewall than the A8’s 45 series tires.

Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires available on the S-Class can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. The A8 doesn’t offer run-flat tires.

Suspension and Handling

The S-Class’ drift compensation steering can automatically compensate for road conditions which would cause the vehicle to drift from side to side, helping the driver to keep the vehicle straight more easily. The A8 doesn’t offer drift compensation steering.

For a smoother ride and more stable handling, the S-Class’ wheelbase is 1.5 inches longer than on the A8 (124.6 inches vs. 123.1 inches). The Maybach S-Class’ wheelbase is 9.4 inches longer than on the A8 (132.5 inches vs. 123.1 inches).

For better maneuverability, the S AMG S 65’s turning circle is 4.1 feet tighter than the A8’s (38.1 feet vs. 42.2 feet). The S 450/560’s turning circle is 1.8 feet tighter than the A8’s (40.4 feet vs. 42.2 feet).

Passenger Space

The S-Class has 1.4 inches more front headroom, .6 inches more front shoulder room and 1.5 inches more rear shoulder room than the A8.

Cargo Capacity

The S-Class has a much larger trunk than the A8 (16.3 vs. 12.5 cubic feet).

Ergonomics

The S-Class has a standard remote vehicle starting system, so the vehicle can be started from inside the driver's house. This allows the driver to comfortably warm up the engine before going out to the vehicle. The climate system will also automatically heat or cool the interior. The A8 doesn’t offer a remote starting system.

Heated windshield washer fluid is standard on the S-Class to defrost the washer nozzles and quickly clear ice and frost from the windshield without scraping. The A8 doesn’t offer heated windshield washer fluid.

The S-Class’ optional Active Parking Assist can parallel park or back into a parking spot by itself, with the driver only controlling speed with the brake pedal. The A8 doesn’t offer an automated parking system.

Model Availability

The Mercedes S-Class comes in coupe, convertible and sedan bodystyles; the Audi A8 isn’t available as a coupe or convertible.

The S-Class is available in both rear-wheel drive and all-wheel drive configurations. The A8 doesn’t offer a two-wheel drive configuration.

Recommendations

Consumer Reports® recommends the Mercedes S-Class, based on reliability, safety and performance.

The Mercedes S-Class outsold the Audi A8/S8 by over 11 to one during the 2018 model year.

© 1991-2018 Advanta-STAR Automotive Research. All rights reserved.

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