by Marcus B. Fitzhugh
The C-Class sedan is the best-selling Mercedes-Benz model. Currently, there are four C-Class models; the C63 AMG, C350 Sport, C300 Luxury and C300 Sport. Both C300 models are available with optional 4MATIC all-wheel drive. There are a few changes in the 2011 C-Class model. The Sport models are now equipped with LED daytime running lights, and black inlays around the headlights. All C-Class models come with new headlight switches, and the ESP controls have been relocated to the instrument cluster.
At 451 horsepower, the C63 AMG is the most powerful model in the C-Class lineup. For those who want a little more, Mercedes-Benz offers a new performance option- the AMG Development Package. This new option features new lightweight forged pistons, connecting rods, crankshaft, and a modified engine management system. This package produces an additional 27 horsepower, for a total of 481. The AMG Development Package also includes a track-calibrated sport suspension, limited slip differential, red brake calipers, a carbon-fiber rear spoiler and its electronic speed limiter has been increased to 174 mph.
C-Class Sport models are equipped with standard AMG styling. This includes deeper front and rear aprons as well as sculpted rocker panels. They also feature five-spoke 17-inch wheels in staggered-widths, sport stabilizer bars, and performance shocks & springs that lower the car by approximately a half-inch. Rather than the traditional four-spoke wheel and burl walnut trim that comes standard on the Luxury model, Sport models come with three-spoke steering wheels and a choice of aluminum, burl walnut or black birdseye maple interior trim. The C300 Sport is also available with a six-speed manual transmission.
All C-Class models have Agility Control. This provides the benefits of both soft and stiff shock absorbers. This is achieved by using twin-tube shock absorbers that are equipped with a hydraulic by-pass piston. This allows the shock to perform in both soft and firm modes. This effectively dampens road noise and tire vibration, while allowing the suspension to retain crisp steering and handling.
The C-Class comes with an "Eco/Sport" button. In the Sport mode, understeer and body lean are reduced. It also quickens throttle response, increases steering feel and raises shift points for maximum performance. In the Eco mode, shift points are lowered, and the vehicle starts off in second gear for optimized fuel economy.
The optional 4MATIC Four-Wheel Drive
Modern all-wheel-drive systems are becoming more refined. As a result, they are becoming increasingly popular, especially in the luxury car market. Unlike older systems, the weight and fuel economy tradeoffs are insignificant with a modern 4MATIC drivetrain. The benefits are full-time four-wheel drive, which provides year-round traction and stability on both wet and dry roads.
The current system made its debut on the current-generation S-Class. This latest version of the Mercedes-Benz 4MATIC all-wheel-drive system is also optionally available on the C300 Sport and the C300 Luxury models. The 4MATIC's full-time all-wheel-drive system is cleanly integrated into the seven-speed automatic transmission and it fits right into the standard C-Class body, utilizing the existing front suspension. The extra gears and shafts that drive the front wheels, add a mere 145 pounds.
The C-Class standard equipment list includes a power sunroof, eight-way power front seats with lumbar support, two-zone automatic climate control, Bluetooth connectivity and a central controller with a five-inch display screen.
The display in the center of the speedometer is linked to a 12-button multi-function steering wheel that can be used to retrieve an abundance of useful information. The display can show phone and audio system information such as radio station, CD track or iPod playlist as well as range, fuel mileage and oil temperature. If the car is equipped with the optional navigation system, the display will also show next-turn directions.
The eight-speaker audio system includes an auxiliary connector port for iPod and MP3-type devices, and a wireless Bluetooth interface that allows a phone to be operated through the audio system.
With the optional Multimedia Package, tracks stored on a data CD, DVD or memory card can also be played through the audio system. An optional six-disc, in-dash CD changer is available as well. The C-Class also has "MusicRegister". This allows the copying of CDs to a six-gigabyte hard drive. This hard drive can store up to 1,500 tracks from audio CDs. A Gracenote database will automatically identify each track with its title, artist, album name and other information.
Navigation When equipped with the optional COMAND audio and navigation system, a power-operated seven-inch display screen slides out and up when the flip-up cover is raised. The display is used by the navigation system to show maps for all of North America. Those maps are stored on a 40-gigabyte hard drive. In addition to the map display, the next-turn navigation instructions can also be shown in the instrument cluster central display.
Renowned Mercedes-Benz Safety
The 2011 C-Class comes with all the safety features expected from Mercedes-Benz - from four-wheel disc brakes and ABS anti-lock brakes, to traction control and ESP stability control. The C-Class boasts nine supplemental restraints, including two-stage front air bags, a knee air bag for the driver, and pelvic air bags which work together with curtain and side air bags to provide extra protection for front occupants in dangerous side-impact collisions.
The big guns - the C63 AMG
There is no shortage of sport sedans. BMW, Audi, Nissan, Toyota, and a host of others build "sports sedans". When it comes to performance, the C63 AMG is in a completely different league. It's like baseball. The local high school basketball team may look pretty good. The Los Angeles Lakers play basketball too. The same rules apply, but the two aren't comparable. Other manufacturers build sports sedans, but they can't be compared to a C63.
The C63 AMG is powered by the first engine developed entirely by AMG. The engine block is a closed deck design, made of a pressure cast, high-strength silicon-aluminum alloy. It has a forged steel crankshaft with heavy metal core plugs in the counterweights. The crank is held in place by main bearings supported by a rigid bedplate. This design came directly from Mercedes-Benz Motorsports. With a bedplate design, the caps won't walk and the main bearings will wear like an engine with a low redline.
Hydraulically cracked forged steel connecting rods ride on the crank. Ultra-light cast aluminum pistons (Development Package models use forged pistons) with cooling oil jets top off the rods. The pistons ride in the world's first production engine to feature cylinder bores with twin-wire-arc-spray (TWAS) coating. TWAS is a process that creates a very low friction surface, which is twice as hard as conventional steel.
Dual overhead cam aluminum heads with four valves per cylinder top off the block. These heads feature variable valve timing. Both intake and exhaust duration is varied over 42 degrees based on engine load and speed. Changes in camshaft duration are electro-hydraulically driven, and controlled by the ECU. The cams use bucket tappets (rather than rocker arms) and are topped by a variable intake manifold. The intake and exhaust ports are designed to form a straight line through the engine. High-flow intake and exhaust ports help the 63 rev freely to over 7,000 rpm, yet the highly flexible V8 still produces nearly 90 percent of its peak torque at only 2,000 rpm.
The end result is a V8 that produces 451 horsepower and 443 lb.-ft. of torque. However, Mercedes-Benz didn't simply build a mega-horsepower C-Class - it's a complete package.
AMG Speedshift Plus
Power is transmitted to the rear wheels of the C63 AMG through a seven-speed AMG automatic transmission that can be shifted manually by either a conventional lever or Formula-1 style shift paddles on the AMG sport steering wheel.
The AMG transmission gives performance-minded drivers complete control of shifting. In manual mode, the AMG transmission doesn't intervene to cause any automatic shifting. Even at maximum engine speed, upshifts will not occur. The same is true for downshifts- under full load, the transmission stays in the gear selected. While in automatic mode, "AMG Speedshift Plus" handles the gear selection and shifting. AMG Speedshift Plus provides 35 percent faster gear shifts and torque converter lockup from 1st gear.
Regardless of mode, the C63 AMG features automatic rev-matching during downshifts. This virtually jolt-free downshifting process reduces load-change handling response, and for motorsports-minded drivers, improves braking in advance of turn-in.
The body has subtle changes. Many people notice the 6.3 AMG badges on each front fender, but there's more to the exterior. The C63 has contoured side sill skirts that carry the aggressive lines of the front end to the rear. The rear has an AMG apron with a black air diffuser insert and three diffuser fins to help enhance aerodynamic performance at high speeds. An AMG lip spoiler resides on the trunk lid and a pair of twin tailpipes completes the look and sound.
Inside the C63 AMG, drivers are greeted by AMG sport seats with integral head restraints that are finished in a special cross piping. The steering wheel is an AMG three-spoke sport piece with aluminum shift paddles. The AMG menu in the central display includes "Warmup," "Setup," and "Race" modes that can be viewed using the steering wheel's multi-function buttons. "Warmup" displays engine oil and coolant temperatures. "Setup" shows the current ESP and transmission shift modes. For those owners who enjoy adjusting their vehicles to even higher limits, "Race" activates a lap timer.
The C63 AMG is also the first AMG model with a three-stage ESP system. In addition to its normal "ESP ON" operation, the ESP button on the center console has an "ESP SPORT" mode as well as "ESP OFF." The ESP Sport mode allows for more aggressive driving with higher drift angles, which can make sporty driving more fun, not to mention more helpful on the race track.
Mechanically, the C63 AMG chassis features a redesigned front suspension. This includes stiffer shocks and springs all around. It has special rebound buffer springs in the front shocks, as well as new bearings, a stiffer stabilizer bar and 1.4-inch wider track. Thanks to a modified steering axis and a stiffer insulating disc in the steering column, its speed-sensitive rack-and pinion steering feels even faster than its 13.6:1 ratio.
Out back, AMG has re-engineered the multi-link suspension. The track is a half-inch wider, with increased negative camber for improved cornering. To handle the increased power, stronger halfshafts and driveshaft joints are used.
Staggered-width 18-inch wheels (8.5 inches in front, 9.0 at the rear) make room for large AMG vented and perforated four-wheel disc brakes. The front discs are 14.2 inches in diameter, and use six-piston fixed calipers. The rear discs are 13 inches and use four-piston fixed calipers.
The AMG Development Package comes with an even stiffer sport suspension, limited slip differential, red brake calipers, carbon-fiber rear spoiler and a higher speed limiter of 174 mph.
The new C has something for everyone.
Photos and Specifications courtesy of Mercedes-Benz USA
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