Certified Benz & Beemer Compares 2015 Mercedes Benz SL-Class VS 2015 BMW 6 Near Phoenix, AZ

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2015 Mercedes Benz SL-Class

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2015 BMW 6

Safety Comparison

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’ 2014 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 second in reliability, above the industry average. With 26 more problems per 100 vehicles, BMW is ranked 11th.

Engine Comparison

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



SL400 3.0 turbo V6

329 HP

354 lbs.-ft.

SL550 4.7 turbo V8

429 HP

516 lbs.-ft.

SL63 AMG 5.5 turbo V8

577 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

502 lbs.-ft.

M6 Competition Package 4.4 turbo V8

575 HP

500 lbs.-ft.

As tested in Motor Trend the SL63 AMG than the BMW 6 Series (automatics tested):



M6 Competition Pack

Zero to 60 MPH

3.5 sec

3.9 sec

4 sec

Quarter Mile

11.8 sec

12.3 sec

12.1 sec

Speed in 1/4 Mile

123 MPH

115.2 MPH

123.1 MPH

Fuel Economy and Range Comparison

On the EPA test cycle the SL65 AMG gets better fuel mileage than the M6 Auto (14 city/21 hwy vs. 14 city/20 hwy).

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

The SL-Class SL63/SL65 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 6 Series doesn’t offer ceramic brake rotors.

The SL-Class stops much shorter than the 6 Series:


6 Series

70 to 0 MPH

152 feet

168 feet

Car and Driver

60 to 0 MPH

102 feet

116 feet

Motor Trend

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 SL63 AMG handles at .97 G’s, while the 650i Convertible pulls only .87 G’s of cornering force in a Motor Trend skidpad test.

The SL63 AMG executes Motor Trend’s “Figure Eight” maneuver 2.5 seconds quicker than the 650i Convertible (23.9 seconds @ .88 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 feet tighter than the 6 Series’ (36.4 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 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.

As tested by Car and Driver, the interior of the SL63 AMG is quieter than the M6 Convertible:


6 Series

At idle

49 dB

52 dB


83 dB

87 dB

70 MPH Cruising

68 dB

73 dB

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).

To make loading and unloading groceries and cargo easier, especially for short adults or children, the SL-Class offers an optional power trunk, which opens and closes automatically by pressing a button, or optionally by just kicking your foot under the back bumper, completely leaving your hands free. The 6 Series doesn’t offer a power trunk.

Ergonomics Comparison

To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the SL-Class has standard extendable sun visors. The 6 Series doesn’t offer extendable visors.

The SL-Class’ standard air conditioned front seats cool the driver and front passenger and help take the sting out of hot leather in Summer. Air conditioned front seats cost extra on the 6 Series.

Economic Advantages Comparison

The SL-Class will cost the buyer less in the long run because of its superior resale value. Kiplinger’s estimates that the SL-Class will retain 48% of its original price after three years, while the 6 Series only retains 43% to 46%.

Recommendations Comparison

Car and Driver performed a comparison test in its May 2013 issue and they ranked the Mercedes SL63 AMG two places higher than the BMW M6 Convertible.

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