For enhanced safety, the front and rear seat shoulder belts of the Mercedes CL-Class have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision. The Porsche 911 doesn’t offer pretensioners for the rear seat belts.
The CL-Class’ front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The 911 doesn’t offer pre-crash pretensioners.
The CL-Class has standard front and rear seat side-impact airbags and head airbags, which act as a forgiving barrier between the passengers and the door. Combined with high-strength steel door beams this system increases protection from broadside collisions. The 911 doesn't offer rear-seat side-impact airbags, only ones for front seat occupants.
The CL-Class has standard NECK-PRO Front Head Restraints, which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the NECK-PRO Front Head Restraints system moves the headrests forward to prevent neck and spine injuries. The 911 doesn’t offer a whiplash protection system.
The CL-Class offers optional PRE-SAFE Brake, which use 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 911 doesn't offer crash mitigation brakes.
An active infrared night vision system optional on the CL-Class helps the driver to more easily detect people, animals or other objects in front of the vehicle at night. Using an infrared camera and near-infrared lights to detect heat, the system then displays the image on a monitor in the dashboard and even aims one of the vehicle’s headlights in the direction of the person or object. The 911 doesn’t offer a night vision system.
The CL-Class’ optional lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. The 911 doesn’t offer a lane departure warning system.
The CL-Class’ optional blind spot warning system uses digital cameras monitored by computer to alert the driver to moving objects in the vehicle’s blind spots where the side view mirrors don’t reveal them and moves the vehicle back into its lane. The 911 doesn’t offer a system to reveal objects in the driver’s blind spots.
The CL-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 911 doesn’t offer a driver alert monitor.
The CL-Class has standard mbrace, 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 911 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 CL-Class and the 911 have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, plastic fuel tanks, four-wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
The Mercedes CL-Class weighs 1266 to 1898 pounds more than the Porsche 911. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.
There are over 55 percent more Mercedes dealers than there are Porsche dealers, which makes it much easier should you ever need service under the CL-Class’ warranty.
The 911’s redline is at 7800 RPM, which causes more engine wear, and a greater chance of a catastrophic engine failure. The CL-Class has a 5950 to 6500 RPM redline.
The CL-Class has more powerful engines than the 911:
Horsepower |
Torque |
|
CL550 4.7 turbo V8 |
429 HP |
516 lbs.-ft. |
CL600 5.5 turbo V12 |
510 HP |
612 lbs.-ft. |
CL63 5.5 turbo V8 |
536 HP |
590 lbs.-ft. |
CL63 5.5 turbo V8 |
563 HP |
664 lbs.-ft. |
CL65 6.0 turbo V12 |
621 HP |
738 lbs.-ft. |
911 3.4 DOHC 6 cyl. |
350 HP |
287 lbs.-ft. |
911 S 3.8 DOHC 6 cyl. |
400 HP |
325 lbs.-ft. |
911 S 3.8 DOHC 6 cyl. |
430 HP |
325 lbs.-ft. |
The CL-Class has 6.9 gallons more fuel capacity than the 911 RWD’s standard fuel tank (23.8 vs. 16.9 gallons), for longer range between fill-ups. The CL-Class has 5.8 gallons more fuel capacity than the 911 Carrera 4’s standard fuel tank (23.8 vs. 18 gallons).
For better stopping power the CL-Class’ front brake rotors are larger than those on the 911:
CL550 |
CL63/CL65 |
911 |
911 |
|
Front Rotors |
13.2 inches |
15.4 inches |
13 inches |
13.8 inches |
Rear Rotors |
11.8 inches |
14.4 inches |
13 inches |
13.8 inches |
For better traction, the CL-Class has larger standard tires than the 911 (255/45R18 vs. 235/40R19). The CL-Class’ optional front tires are larger than the largest tires available on the 911 (255/40R19 vs. 245/35R20).
The CL-Class has a standard space-saver spare tire so you can replace a flat tire and drive to have the flat repaired or replaced. A spare tire isn’t available on the 911, it requires you to depend on roadside assistance and your vehicle will have to be towed.
The front and rear suspension of the CL-Class uses air springs for a smoother, controlled ride than the 911, which uses coil springs. Air springs maintain proper ride height and ride more smoothly.
The CL-Class CL600/CL63/CL65 offers an available active suspension system, which counteracts cornering forces actively, limiting body roll and improving handling and stability. Porsche doesn’t offer an active suspension on the 911.
The CL-Class has a standard automatic front and rear load leveling suspension to keep ride height level with a heavy load or when towing. The 911 doesn’t offer a load leveling suspension.
The CL-Class 63/600/65’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 911 doesn’t offer drift compensation steering.
For a smoother ride and more stable handling, the CL-Class’ wheelbase is 19.8 inches longer than on the 911 (116.3 inches vs. 96.5 inches).
For better handling and stability, the track (width between the wheels) on the CL-Class is 2.6 inches wider in the front and 3.5 inches wider in the rear than the average track on the 911.
The CL-Class’ front to rear weight distribution is more even (56% to 44%) than the 911’s (38.2% to 61.8%). This gives the CL-Class more stable handling and braking.
The design of the Mercedes CL-Class amounts to more than styling. The CL-Class has an aerodynamic coefficient of drag of .27 Cd. That is lower than the 911 (.29 to .31). A more efficient exterior helps the CL-Class go faster and keeps the interior quieter. It also helps the CL-Class get better fuel mileage.
As tested by Road & Track, the interior of the CL550 4MATIC is quieter than the 911 S Coupe:
CL-Class |
911 |
|
At idle |
47 dB |
55 dB |
Full-Throttle |
73 dB |
77 dB |
50 MPH Cruising |
77 dB |
84 dB |
70 MPH Cruising |
70 dB |
87 dB |
The CL-Class has 8.4 inches more front shoulder room, 5.4 inches more rear headroom, 7.2 inches more rear legroom and 6.9 inches more rear shoulder room than the 911 Coupe.
The CL-Class has a much larger trunk than the 911 Coupe with its rear seat up (13.5 vs. 4.76 cubic feet). The CL-Class has a much larger trunk with its rear seat folded than the 911 Coupe with its rear seat folded (13.5 vs. 11.9 cubic feet).
With its coupe body style, valet key and remote trunk release lockout, the CL-Class offers cargo security. The 911’s non-lockable folding seat and non-lockable remote release defeat cargo security.
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