There's really only one question that needs be answered about the 2004 Mercedes-Benz E55 AMG: Yes, it's fast. The dual-twin-outlet exhaust system's inside diameter is only 70mm, versus 90mm for the SL55, S55 and CL55. That restricts flow, reducing rated horsepower from 493 to a mere 469 bhp, but the E55's 3,800-to-3,900-lb estimated curb weight (figures had not been finalized with the pre-production cars) makes it noticeably faster by the seat of the pants than Mercedes' 4,400-lb heavyweights. Mercedes reports it takes just 4.7 sec. for the 0-to-62-mph sprint.
Detroit certainly claims responsibility for the cheapest V8s in the world, but hardly the nicest nor most powerful. Mercedes-Benz's entry in that contest is a 24-valve unit which its maker states makes peak power at 6100 rpm and delivers its maximum torque of 560 lb-ft (700 Nm) from 2650 to 4500 rpm. This performance is made possible by a Lysholm-type twin-screw compressor (developed just for AMG by partially DaimlerChrysler-owned Japanese affiliate IHI), and an air-to-liquid intercooler to 5439cc of displacement. Maximum boost is 0.9 bar (slightly more than 13 psi). The Lysholm-type compressor has internal compression, increasing its efficiency at high boost levels. That also means it compresses any air that passes through it, which takes energy. Mercedes deactivates the compressor for low-load operation via an electromagnetic clutch, as well as providing the usual air bypass.
The compressor and intercooler are integrated into the intake manifold, but AMG did not simply add this hardware to an existing engine; virtually every part was changed to increase output or enhance durability. Cooling air intakes, fans and heat exchangers have all been fortified to support the supercharged engine. The software controlling Mercedes' five-speed automatic transmission was also recalibrated by AMG engineers for maximum sporting performance, and cooling fins added to the rear differential lower its temperature by as much as 20*C.
Beginning with the previous E55 AMG, the tuning division has had input on the basic design of all Mercedes-Benz chassis, ensuring each will have the essential ingredients necessary to create a sporting machine. Active Body Control has been an excellent option on high-line Mercedes products for several years; the new E55 AMG debuts a refinement called Airmatic, in which both damping and spring rate are variable, as well as controlling ride height with varying load.
The spring rate of a gas spring depends on two things: pressure and volume. Increasing pressure by adding gas to the working chamber wouldn't work; it would simply raise the ride height. Instead, AMG engineers used two selectable working reservoir chambers. Opening both gives the lowest spring rate, closing off the small one gives an intermediate rate, and changing from the large to the small chamber gives the highest spring rate.
Ride height begins 10mm lower than the standard E-Class and drops another 15mm when 140 km/h is reached, returning to normal height at 70 km/h. Dampers are electronically adjusted. Suspension settings can be changed continuously by a computer based on driving conditions, or any of the three settings can be selected manually. Anti-roll bars are 50% stiffer than those of the E500.
Sensotronic Brake Control (SBC) is adapted from the SL55 AMG roadster, a system that is trivialized by explaining it as "brake-by-wire." In front, 360x36mm rotors are gripped by eight-piston calipers. In the rear, 330x26mm rotors are squeezed by four pistons. All components are unique to AMG. The electronic control integrates many supplemental features common with the most advanced conventional braking systems, such as BrakeAssist and a more complete, easier-to-engineer interface with the Electronic Stability Program (ESP), as well as adding some refinements.
New 18-in. wheels were designed to accommodate the brakes; the rims are 8-in. wide in front and 9 in. out back with 245/40ZR18 and 265/35ZR18 tires. I was told production castings would have vermiculite inserts to reduce weight by 20%, but the pre-production car I drove lacked this feature.
Exterior enhancements include bi-xenon headlights, lower body trim all around and four exhaust exits. Distinctive badging is easily removable for customers who prefer to travel in stealth mode. Inside, newly developed AMG sport seats, rear seats and doors are trimmed in an exclusive nappa/nubuck leather with contrasting stitching. Instrument panel details, steering wheel and door sills further distinguish the E55 AMG from its lesser brethren.
In the German countryside, the navigation system finally seemed like a good idea. Without having seen the sun in two days, neither person in the car had any sense of direction, and the map we had did little to alleviate our perpetual lostness. Putting our faith blindly in the navigation system proved utterly reliable.
Narrow roads and rainy, German October weather warned against exploring the E55 AMG's limits in other than a straight line, but that proved sufficient to excite. Both I and my co-driver noticed a slight bump-steer in the rear, which merits further investigation. We eagerly await more extensive driving of Mercedes-Benz' fastest car in Southern California's usual conditions of sunshine, lousy freeway pavement and endless ribbons of perfect, winding two lanes.