Certified Benz and Beemer Compares 2013 Mercedes Benz SL-Class VS 2013 BMW 6 Near Scottsdale, AZ

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2013 Mercedes Benz SL-Class

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2013 BMW 6

Safety Comparison

The SL-Class’ front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 6 Series doesn’t offer pre-crash pretensioners.

The SL-Class offers an optional PRE-SAFE Brake, which uses forward mounted sensors to warn the driver of a possible collision ahead. If the driver doesn’t react and the system determines a collision is imminent, it automatically applies the brakes at full-force in order to reduce the force of the crash or avoid it altogether. The 6 Series doesn't offer crash mitigation brakes.

The SL-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 6 Series doesn’t offer a driver alert monitor.

Both the SL-Class and the 6 Series have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control and electronic stability systems to prevent skidding.

Reliability Comparison

J.D. Power and Associates’ 2012 Initial Quality Study of new car owners surveyed provide the statistics that show that Mercedes vehicles are better in initial quality than BMW vehicles. J.D. Power ranks Mercedes 9th in initial quality, above the industry average. With 1 more problems per 100 vehicles, BMW is ranked 10th.

J.D. Power and Associates’ 2012 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Mercedes vehicles are more reliable than BMW vehicles. J.D. Power ranks Mercedes 6th in reliability, above the industry average. With 42 more problems per 100 vehicles, BMW is ranked 20th.

Engine Comparison

The SL-Class has more powerful engines than the 6 Series:



SL550 4.7 turbo V8

429 HP

516 lbs.-ft.

SL63 AMG 5.5 turbo V8

530 HP

590 lbs.-ft.

SL63 AMG 5.5 turbo V8

557 HP

664 lbs.-ft.

SL65 AMG 6.0 turbo V12

621 HP

738 lbs.-ft.

640i 3.0 turbo 6 cyl.

315 HP

330 lbs.-ft.

650i 4.4 turbo V8

445 HP

480 lbs.-ft.

M6 4.4 turbo V8

560 HP

500 lbs.-ft.

Fuel Economy and Range Comparison

On the EPA test cycle the SL63 AMG gets better fuel mileage than the M6 RWD Auto (16 city/25 hwy vs. 14 city/20 hwy).

Regardless of its engine, the SL-Class’ engine automatically turns off when the vehicle is stopped, saving fuel and reducing pollution. (Start/Stop isn’t accounted in present EPA fuel mileage tests.) BMW only offers an automatic engine start/stop system on the 6 Series 640i/M6.

The SL-Class has 1.3 gallons more fuel capacity than the 6 Series’ standard fuel tank (19.8 vs. 18.5 gallons), for longer range between fill-ups.

Brakes and Stopping Comparison

For better stopping power the SL-Class’ standard front brake rotors are larger than those on the 6 Series:


6 Series

Front Rotors

14.2 inches

13.7 inches

Tires and Wheels Comparison

For better traction, the SL-Class has larger tires than the 6 Series (F:255/40R18 & R:285/35R18 vs. 245/45R18).

The SL-Class’ standard 255/40R18 front and 285/35R18 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 640i’s standard 45 series tires.

Suspension and Handling Comparison

The SL-Class offers an optional automatic front and rear load leveling suspension to keep ride height level with a heavy load or when towing. The 6 Series doesn’t offer a load leveling suspension.

The SL550 handles at .94 G’s, while the 650i Convertible pulls only .87 G’s of cornering force in a Motor Trend skidpad test.

The SL550 executes Motor Trend’s “Figure Eight” maneuver 1.4 seconds quicker than the 650i Convertible (25 seconds @ .73 average G’s vs. 26.4 seconds @ .67 average G’s).

For better maneuverability, the SL550’s turning circle is 2.2 feet tighter than the 6 Series’ (36.2 feet vs. 38.4 feet). The SL63/SL65’s turning circle is 2.1 feet tighter than the 6 Series’ (36.3 feet vs. 38.4 feet).

Chassis Comparison

The SL-Class is 11.2 inches shorter than the M6 Convertible, making the SL-Class easier to handle, maneuver and park in tight spaces.

The design of the Mercedes SL-Class amounts to more than styling. The SL-Class has an aerodynamic coefficient of drag of .29 Cd. That is lower than the 6 Series (.32) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the SL-Class get better fuel mileage.

The SL-Class’ standard power retractable hardtop allows a seamless transition from an open car, to a completely sealed coupe. The 6 Series doesn’t offer a retractable hardtop.

Cargo Capacity Comparison

The SL-Class has a much larger trunk with its top up than the 6 Series Convertible with its top up (13.5 vs. 12.4 cubic feet).

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