2019 Mercedes C-Class Sedan vs. 2018 Audi A3 Sedan

Detailed Review, Specifications & Comparison

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Safety

The C-Class Sedan offers an optional Surround View System to allow the driver to see objects all around the vehicle on a screen. The A3 Sedan only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.

The C-Class Sedan’s 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 A3 Sedan doesn’t offer a driver alert monitor.

The C-Class Sedan has standard Mercedes-Benz Emergency Call, which uses a global positioning satellite (GPS) receiver and a cellular system to get turn-by-turn driving directions, 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 A3 Sedan 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 C-Class Sedan and the A3 Sedan have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, height adjustable front shoulder belts, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available all wheel drive, lane departure warning systems, blind spot warning systems and rear cross-path warning.

The National Highway Traffic Safety Administration does 35 MPH front crash tests on new vehicles. In this test, results indicate that the Mercedes C-Class Sedan is safer than the Audi A3 Sedan:

 

C-Class Sedan

A3 Sedan

 

Driver

STARS

5 Stars

4 Stars

HIC

138

217

Neck Injury Risk

24%

45%

Neck Stress

203 lbs.

427 lbs.

Neck Compression

62 lbs.

143 lbs.

Leg Forces (l/r)

421/449 lbs.

461/426 lbs.

New test not comparable to pre-2011 test results. More stars = Better. Lower test results = Better.

The National Highway Traffic Safety Administration does side impact tests on new vehicles. In this test, which crashes the vehicle into a flat barrier at 38.5 MPH and into a post at 20 MPH, results indicate that the Mercedes C-Class Sedan is safer than the Audi A3 Sedan:

 

C-Class Sedan

A3 Sedan

 

Front Seat

STARS

5 Stars

5 Stars

HIC

76

172

Chest Movement

1 inches

1.1 inches

Abdominal Force

147 G’s

219 G’s

 

Into Pole

STARS

5 Stars

5 Stars

HIC

248

333

Spine Acceleration

43 G’s

47 G’s

New test not comparable to pre-2011 test results. More stars = Better. Lower test results = Better.

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 C-Class Sedan’s warranty.

Reliability

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 C 300 Sedan’s standard 2.0 turbo 4 cyl. produces 69 more horsepower (255 vs. 186) and 52 lbs.-ft. more torque (273 vs. 221) than the A3 Sedan’s standard 2.0 turbo 4 cyl. The C 300 Sedan’s 2.0 turbo 4 cyl. produces 35 more horsepower (255 vs. 220) and 15 lbs.-ft. more torque (273 vs. 258) than the A3 Sedan’s optional 2.0 turbo 4 cyl. The AMG C 43 Sedan’s standard 3.0 turbo V6 produces 165 more horsepower (385 vs. 220) and 126 lbs.-ft. more torque (384 vs. 258) than the A3 Sedan’s optional 2.0 turbo 4 cyl.

Fuel Economy and Range

In heavy traffic or at stoplights the C-Class Sedan’s engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. The engine is automatically restarted when the driver gets ready to move again. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) The A3 Sedan doesn’t offer an automatic engine start/stop system.

The C-Class Sedan has 4.2 gallons more fuel capacity than the A3 Sedan FWD’s standard fuel tank (17.4 vs. 13.2 gallons), for longer range between fill-ups. The C-Class Sedan has 2.9 gallons more fuel capacity than the A3 Sedan Quattro’s standard fuel tank (17.4 vs. 14.5 gallons).

Transmission

A nine-speed automatic is standard on the Mercedes C-Class Sedan, for better acceleration and lower engine speed on the highway. Only a seven-speed automatic is available for the A3 Sedan.

Brakes and Stopping

For better stopping power the C-Class Sedan’s brake rotors are larger than those on the A3 Sedan:

 

C 300

AMG C 43

A3

Front Rotors

13 inches

14.2 inches

12.3 inches

Rear Rotors

11.8 inches

12.6 inches

10.7 inches

The C-Class Sedan’s standard front and rear disc brakes are vented to help dissipate heat for shorter stops with less fading. The rear discs on the A3 Sedan are solid, not vented.

The C-Class Sedan stops much shorter than the A3 Sedan:

 

C-Class

A3

 

60 to 0 MPH

105 feet

121 feet

Motor Trend

Tires and Wheels

Changing a flat tire near traffic can be dangerous and inconvenient. The run-flat tires available on the C-Class Sedan can be driven up to 50 miles without any air pressure, allowing you to drive to a service station for a repair. The A3 Sedan doesn’t offer run-flat tires.

Suspension and Handling

The C-Class Sedan offers an available driver-adjustable suspension system. It allows the driver to choose between an extra-supple ride, reducing fatigue on long trips, or a sport setting, which allows maximum control for tricky roads. The A3 Sedan’s suspension doesn’t offer adjustable shock absorbers.

The C-Class Sedan’s 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 A3 Sedan doesn’t offer drift compensation steering.

For a smoother ride and more stable handling, the C-Class Sedan’s wheelbase is 8 inches longer than on the A3 Sedan (111.8 inches vs. 103.8 inches).

The C-Class Sedan’s front to rear weight distribution is more even (53% to 47%) than the A3 Sedan’s (58.1% to 41.9%). This gives the C-Class Sedan more stable handling and braking.

The C 300 Sedan handles at .91 G’s, while the A3 Sedan Premium Quattro pulls only .87 G’s of cornering force in a Motor Trend skidpad test.

Chassis

The front grille of the C-Class Sedan uses electronically controlled shutters to close off airflow and reduce drag when less engine cooling is needed. This helps improve highway fuel economy. The A3 Sedan doesn’t offer active grille shutters.

Passenger Space

Because it has more passenger and cargo room, the EPA rates the C-Class Sedan a Compact car, while the A3 Sedan is rated a Subcompact.

The C-Class Sedan has 4 cubic feet more passenger volume than the A3 Sedan (90 vs. 86).

The C-Class Sedan has .6 inches more front headroom, .5 inches more front legroom, .5 inches more front shoulder room, 1 inch more rear headroom, .1 inches more rear legroom and 2 inches more rear shoulder room than the A3 Sedan.

Cargo Capacity

The C-Class Sedan has a larger trunk than the A3 Sedan (12.6 vs. 12.3 cubic feet).

With its sedan body style, valet key, locking rear seatbacks and remote trunk release lockout, the C-Class offers cargo security. The A3 Sedan’s non-lockable folding seat and non-lockable remote release defeat cargo security.

To make loading and unloading groceries and cargo easier when your hands are full, the C-Class Sedan’s power trunk can be opened or closed just by kicking your foot under the back bumper, leaving your hands completely free. The A3 Sedan doesn’t offer a power or hands-free opening trunk.

Servicing Ease

The engine in the C-Class Sedan is mounted longitudinally (North-South), instead of sideways, as in the A3 Sedan. This makes it easier to service and maintain, because the accessory belts are in front.

Ergonomics

The C-Class Sedan 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 A3 Sedan doesn’t offer a remote starting system.

When three different drivers share the C-Class Sedan, the memory system makes it convenient for all three. Each setting activates different, customized memories for the driver’s seat (memory seat optional for the front passenger), steering wheel position and outside mirror angle. The A3 Sedan doesn’t offer a memory system.

The C-Class Sedan’s standard easy entry system raises the steering wheel, making it easier for the driver to get in and out. The A3 Sedan doesn’t offer an easy entry system.

The C-Class Sedan offers an optional heads-up display that projects speed and navigation instruction readouts in front of the driver’s line of sight, allowing drivers to view information without diverting their eyes from the road. The A3 Sedan doesn’t offer a heads-up display.

To help drivers see further while navigating curves, the C-Class Sedan offers optional adaptive headlights to illuminate around corners automatically by reading vehicle speed and steering wheel angle. The A3 Sedan doesn’t offer cornering lights.

A power rear sunshade is optional in the C-Class Sedan to help block heat and glare for the rear passengers. The A3 Sedan doesn’t offer a rear sunshade.

When the C-Class Sedan is put in reverse, the passenger rearview mirror tilts from its original position. This gives the driver a better view of the curb during parallel parking maneuvers. Shifting out of reverse puts the mirror into its original position. The A3 Sedan’s mirror doesn’t automatically adjust for backing.

Optional air-conditioned seats in the C-Class Sedan keep the driver and front passenger comfortable and take the sting out of hot seats in summer. The A3 Sedan doesn’t offer air-conditioned seats.

On extremely cold winter days, the C-Class Sedan 300’s optional heated steering wheel provides comfort, allowing the driver to steer safely and comfortably before the car heater warms up. The A3 Sedan doesn’t offer a heated steering wheel.

The C-Class Sedan’s 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 A3 Sedan doesn’t offer an automated parking system.

Economic Advantages

Insurance will cost less for the C-Class Sedan owner. The Car Book by Jack Gillis rates the C-Class Sedan with a number “3” insurance rate while the A3 Sedan is rated higher at a number “5” rate.

According to The Car Book by Jack Gillis, the C-Class Sedan is less expensive to operate than the A3 Sedan because it costs $90 less to do the manufacturer’s suggested maintenance for 50,000 miles. Typical repairs cost less on the C-Class Sedan than the A3 Sedan, including $22 less for a starter, $21 less for fuel injection, $45 less for front struts and $104 less for a timing belt/chain.

Recommendations

The C-Class Sedan was chosen as one of Automobile Magazine’s “All Stars” in 2015. The A3 Sedan has never been an “All Star.”

The Mercedes C-Class outsold the Audi A3/S3 by almost three to one during the 2018 model year.

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

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