Mercedes-Benz | Porsche | Motorcycles & Miscellanea | How Things Work (DIY) Section

something wicked this way comes

When it hit the streets for model year 2001, the CLK55 was fresh, exciting, and the fastest car in the Mercedes-Benz stable. The W208 was supplanted by the W209, but it grew stagnant and was easily overlooked. Yes, it was improved in some areas, but the main problem was the E55. In 2003, the E55 received THE upgrade; der Kompressor. Adding a supercharger upgraded the E from "a very fast car" to ballistic status. The CLK faithful craved the 469 horsepower / 500+ pound-feet of torque, thermonuclear power plant, but that itch remained unscratched. For some, the real anguish was knowing what the factory could have done.

While the CLK55 grew stale, the AMG division initiated a project to build a new engine. In the past, AMG had always modified standard Mercedes-Benz engines. This was different. It was a project to build a "new from the oil pan up", AMG specific engine whose purpose was immense torque, a spacious powerband, and Mercedes-Benz durability.

For this project, lead engineer Bernd Ramler was enticed to leave Porsche (where he had designed the V10 that powered the Carrera GT) and return to Mercedes-Benz. Four years later, Ramler's newest creation, the 63, was presented to the CLK faithful.

In the CLK63, horsepower increased from 362 to 475, while torque leapt from 376 pound-feet to 465. Finally, the CLK acquired "ballistic" status. The CLK63 didn't simply replace the CLK55, the CLK63 obliterated it. Allow me to take a moment and clarify that. "Obliterate" is a verb. It means "to blot out or wear away, leaving no traces of the original object". If one drives a CLK55, and then drives a CLK63, the memory of driving the CLK55 will disappear.

Why? Many people look at the "zero to sixty" figure. That doesn't tell the story. From zero to sixty, the CLK63 is at least a half-second faster than the CLK55. I say "at least" because both cars are severely limited by traction. Once rolling, traction is not an issue, and that's when you can tell the difference. From five miles an hour on up, the CLK63 simply pulls away from the CLK55. They're both electronically limited to 155 MPH, but the CLK63 will be there a lot faster than the CLK55. This is not to imply the CLK55 is slow. It's not. It's just not "CLK63 fast".

The CLK63 brakes have been upgraded to match the additional power. The front rotors are long wearing, fade resistant, composite material. The rears are traditional cast-iron rotors. This combination works well. Repeated late braking exercises did not produce the fade more commonly felt in the CLK55. Although stopping power remained consistent, there is no pedal feel for the first 25% of travel.

In addition to the guttural sounding, naturally aspirated, big horsepower, bigger torque, vee-eight, the CLK63 received a seven-speed transmission. The Mercedes-Benz 7G-Tronic was upgraded to handle the type of torque spikes that would otherwise break the standard seven-speed. The advantage of the 7G-Tronic is it employs close gear spacing. This allows it to keep the engine in a rev range where optimum power delivery is available both before and after gear changes. The results are "pin the occupants to their seats until the 155 MPH speed limiter kicks in" type acceleration. The transmission has three modes; Comfort, Sport, and Manual. These SpeedShift equipped transmissions shift 30% faster in sport mode than they do in comfort mode. In manual mode, the transmission shifts 50% faster. A pair of steering-wheel attached shift paddles allow the driver to make manual gear changes. Personally, I believe the paddles are the correct approach. There was a time when buttons were offered, and they felt disconnected. The paddles feel more precise.

When driven in a normal fashion, the CLK63 behaves the same as a CLK350. The steering feels weighted without excessive feedback, (with the engine revs low) it's relatively quiet, and the suspension is compliant (again, at reasonable speeds). This is exactly what you'd expect from a luxury coupe. With it's visually restrained appearance, no one would guess what lies beneath the hood. There are a few clues. There are small "6.3 AMG" badges on the fenders and it has an AMG specific front bumper. There are AMG-spec wheels, but nothing that screams Pimp My Ride.

The interior is just as subdued as the exterior. There are AMG specific parts - the door sill panels, instrument cluster, and sport seats, but it all looks like it belongs in a Mercedes-Benz.

Although the chassis doesn't relay every bump in the road, it's not numb. As the lateral loads are increased, the chassis relays increased feel, letting the driver know just how much traction is available. Also, ESP is always there to help out. The flickering light is an indication that traction has been lost, and the system is intervening. When the ESP switch is set to 'off', it's more like a watchful parent in the next room. With ESP off, when the vehicle is nanoseconds away from doom, ESP will awaken and intervene. The " ESP off" feature is different on the CLK63, because it waits longer before coming to the rescue - just in case the driver intended to perform a particular maneuver.

There is one downside to the CLK63. It's a personal issue. I'm not a cab guy, I prefer a coupe. I like coupes because there are times when I want to close everything and not hear the outside world. The reduced weight and increased stiffness are also benefits. Unfortunately, the only CLK63 coupes the U.S. received were the Black Series. Coupes were available in Europe and Asia.

CLK55 / CLK63 Technical Data

© 2007 Marcus Blair Fitzhugh

Home | Mercedes-Benz | Porsche | Motorcycles & Miscellanea | How Things Work (DIY) Section