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Autoworld.com - David Lee - Mercedes-Benz
has put the sport in sport utility vehicle with the introduction of
theML55 AMG to its highly successful M-Class model line. Never before has
an SUV been so fast, so luxurious, or handled so well.
Available in limited numbers in early 2000,
this latest M-Class model has been engineered in conjunction with AMG,
Mercedes' long-time high-performance and racing arm. The ML55 is one of
three AMG-inspired Mercedes-Benz cars available to American consumers. The
limited-production C43 and exclusive E55 sedans round out the AMG-tuned
lineup in 2000.
The ML55 AMG is the high-performance variant
of the highly successful ML320 and ML430 models, and was created to
satisfy a very specific automotive consumer -- one who appreciates the
high performance capabilities of a sports car, the luxury of a fine sedan,
and the utility of an off-road recreational vehicle. With a
specially-crafted aluminum V8 engine pumping out 342 horsepower and 376
lbs.-ft of torque, the ML55 AMG has a top speed of nearly 150 mph and can
travel 0 to 60 mph in less than seven seconds. Performance statistics such
as these are usually reserved for the highest performing sports cars.
Additionally, the ML55 AMG's four-wheel-drive capabilities and ample
ground clearance give it the agility to traverse a snowy highway or gravel
country road.
Bambi Meets Godzilla,
Courtesy of AMG
The extraordinary Mercedes-Benz CLK-GTR race
cars that have captured the past two FIA GT championships were designed,
built and fielded by AMG. Mercedes-Benz recently purchased a majority
interest in AMG, and will accelerate the introduction of AMG vehicles
across other product lines.
With the exception of the ML55, Mercedes-Benz
passenger cars slated for AMG conversion are shipped from one of several
factories in Europe to the AMG assembly plant in Sindelfingen, Germany.
The ML55,however, which is built in the Mercedes factory in Tuscaloosa,
Alabama, receives the AMG conversion right on the assembly line using AMG-modified
engines, driveline and suspension systems.
Hauling the Bacon with 342 Horses
The ML55 AMG can be easily identified by its muscular physique. Hefty five-spoke, 18-inch wheels and
low-profile 285/50 R 18 tires are covered by sleek fender flares. Clearly visible through the wheels, red brake
calipers (for most body colors) not only provide a fitting accent but also identify the ML55 brakes -- special 13.6-
inch discs in front and 13.5-inch discs at the rear.
Unique rocker panels add to the athletic look. Integrated fog lights are built into the front air dam and a
special panel continues the bumper line across the liftgate. "Power domes" on the front hood harken back to the
legendary Mercedes 300 SL Gullwings and roadsters of the 1950s, and twin chrome exhaust tips also hint at the
power underhood.
The heart of the ML55 is a potent 5.5-liter V8 engine, pumping out 342 horsepower. The engine is an
AMG-modified version of the Mercedes-Benz 5.0-liter V8, which made its debut in the 1999 SL500 roadster. The
larger displacement is the result of a special forged-steel "stroker" crankshaft, which increases overall displacement
from 4,966cc to 5,439cc by adding 8 mm, nearly 1/3 of an inch, to each piston's stroke. The crankshaft is
dynamically balanced, and pistons and connecting rods are selected for each engine in equal weight-matched sets.
The result is a smooth, low vibration power plant that produces a massive 376 lbs. ft. of torque.
To feed the larger engine, AMG modifies the original magnesium intake manifold with a wider cross-section to increase airflow. As in the standard Mercedes manifold, the AMG version features long intake passages
that spiral around to each cylinder. Flaps inside the manifold stay closed below about 3,700 rpm, forcing intake air
to take a long route, building up pressure waves which boost flow and improve low- and mid-range torque. The
flaps open above 3,700 rpm, allowing intake air to take a shorter, more direct route to the cylinders for maximum
high-speed power.
The ML55 engine uses a special electronic control unit to manage the larger V8, and fuel injectors have
been matched to the increased airflow. The ECU fires the fuel injectors, controls ignition timing and determines
precisely when the manifold flaps open and close.
The AMG-massaged engine retains the twin-sparkplug/three-valve, single-overhead cam design, but
replaces the standard camshafts with new modular cams and installs higher-tension valve springs. The hollow
construction of the standard camshafts makes them light, yet the AMG cams are even lighter. Valve sizes are the
same as the stock V8, but the AMG cams provide longer valve duration for increased power.
The Power of a Clydesdale, the Speed of a Cheetah
Harnessing all that horsepower and torque is a full-time four-wheel-drive system providing 50/50 front/rear
torque distribution. One of the most innovative and versatile in the SUV market, the M-Class 4WD system utilizes
front, center and rear "open" differentials that require no driver intervention.
As with all M-Class models, the ML55 AMG stands apart from most other SUVs because it does not lock
its axles in an attempt to maintain traction on slippery or loose surfaces. Instead, the M-Class employs an advanced
electronic full-time four-wheel traction control system. To maintain traction, the system senses slip and applies the
brakes on the slipping wheel, which transfers the fight amount of torque to those wheels with the most grip, on
virtually any road surface. The M-Class system provides mobility even when three wheels lose traction. A two-
speed electronically controlled transfer case gives all M-Class models true off-road capability.
Using traction control rather than locking differentials also aids maneuverability on any surface. In
slippery or off-road conditions, the benefit of the full-time four-wheel-drive system is obvious. Yet even on dry
roads, the system makes its presence known by giving the M-Class models secure, neutral handling
characteristics.
The extraordinary Electronic Stability Program (ESP) helps drivers maintain directional stability, especially
on slippery or gravel-covered roads by preventing oversteer (rear-end "fislitailing) or understeer (front-end
"plowing"). ESP can sense impending loss of control - at either end of the car - then momentarily applies the
brake on one wheel to restore stability, something that even a skilled driver cannot do.
SUV Utility, Passenger Car Comfort and Safety
The interior of the ML55 AMG more closely resembles that of a luxury sedan than a go-anywhere, do-anything sport utility vehicle and sets a new standard, even for M-Class interior features. Thickly bolstered sport
seats are finished in supple leather contrasted by dark burl walnut trim. The armrests and console storage are
leather covered, as is a portion of the walnut and leather AMG steering wheel. The ML55 instrument cluster
features chrome-ringed gauges with white analog faces, while the center console holds a large display featuring an
integral navigation and audio system which is set up for easy add-on of a digital StarTAC integrated portable phone
and/or six-disc CD changer. AMG-embroidered floormats complete the picture.
Beneath the elegance lies a cocoon of safety. Mercedes-Benz M-Class sport utility vehicles introduced the
concept of crash compatibility to the SUV segment. Unlike most sport utility vehicles, the
M-Class frame is also designed so that it will not override a passenger car's body structure in a collision. Such
compatibility can lessen the severity of frontal impacts between vehicles of different categories.
Although the M-Class uses a body-on-frame design, the dynamics of its crash protection are roughly
equal to the Mercedes-Benz E-Class luxury sedan, which has unibody construction. In addition to a front crumple zonebuilt into the nose of the vehicle, the M-Class incorporates a special structure around the windshield pillars. In a
severe collision, this extra crumple zone can actually help dissipate some of the energy around the sides of the
vehicle, providing even more protection for the occupants of both the M-Class and a colliding vehicle.
All M-Class models are equipped with advanced four-channel, four-wheel anti-lock brakes, dual front
airbags, the BabySmart automatic seat recognition system, and this year, side impact airbags in all four doors as
well. The front and rear outboard seatbelts are equipped with both emergency tensioning retractors and belt-force
limiters, and this year the second-row center seat also has a three-point belt.
A Chassis Designed for Safety and Performance
The chassis forming the foundation of all M-Class vehicles sets new SUV standards for ML55
performance, comfort and safety. The M-Class has a unit body mounted to a strong separate frame with closed,
twist-resistant box-profile sections. The two longitudinal and three transverse frame cross
members are welded together for exceptional strength and torsional rigidity. Suspension sub-frames and ten rubber body mounts provide
isolation from road shocks and noise.
The M-Class features independent front and rear suspension, unusual in its segment. Many SUVs have
only independent front suspension, while some even use solid axles front and rear. Four-wheel independent
suspension provides class-leading handling, stability and ride comfort, both on and off road. The Mercedes M-Class also uses rack-and-pinion power steering, and a tight 37-foot turning circle gives the M-Class exceptional
maneuverability on any road.
Moving Cargo in Luxury
All M-Class models were developed with passenger comfort, cargo room and versatility in mind. The
ML55 AMG, as well as the ML320 and ML430, feature the largest side doors in their category, along with a low
18-inch step-in height to make getting in and out of an M-Class much easier than most SUVs. Its
111 -inch wheelbase is among the longest in its segment, while the rear seat has ample head, leg and shoulder room for three
passengers, thanks in part to a relatively flat floor. For added versatility, all M-Class models for 2000 come with a
new 60/40 split fold-down rear seat, with a center armrest.
As with all M-Class models, the ML55 AMG comes equipped with a generous level of standard equipment:
air conditioning with dust and pollen filtration, a high-performance 80-watt Bose audio system, cruise control, tilt
steering column, power windows with express-down in the front, rear wiper, dual heated power side mirrors, an
outside temperature gauge, Homelink-compatible universal garage door opener, alloy wheels, four-way head
restraints, carpeted floor mats, pre-wiring for CD changer and phone, roof rails and a retractable cargo cover.
All 2000 Mercedes-Benz models come with a four-year/50,000-mile warranty, which includes tires,
batteries and adjustments for the full coverage period. Regularly scheduled maintenance during the vehicle's entire
warranty period is also now free of charge. In addition, the 24-hour Mercedes-Benz Roadside Assistance program
covers all Mercedes cars, regardless of model year. This peace of mind can include a free jump-start, a few gallons
of fuel or mounting the spare tire, even for those driving a decades-old Mercedes.
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