2003 Audi RS 6 and 2003 Mercedes-Benz E55 AMG Comparison

With cars as fast as the Audi RS 6 and the Mercedes-Benz E55 AMG, the talk naturally tends to center on speed, speed, speed. But the RS 6 and the E55 AMG are loaded with cool details and innovative features -- and lots of little engineering marvels that tend to get lost in the enormous shadows of their superstar V-8s. Here's a look a just some of the great stuff built into these fabulous four-doors. Also, as you're reading, keep an eye open for an image on each page with wallpaper-sized zooms for your desktop.

Twin turbochargers (Audi)
The 4.2-liter V-8 in the RS 6 makes its incredible 450 horsepower thanks to twin turbochargers, electronically controlled waste gates, and twin intercoolers. The engine features one turbocharger for each cylinder bank; an intercooler mated with each turbocharger prevents loss of turbo pressure while cooling the intake air. Audi's computerized Motronic engine-management system controls boost pressure, knock, and exhaust-gas temperature for enhanced engine efficiency and maximum output.

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Lysholm-Type Supercharger (Mercedes)
The E55 delivers its staggering 469 horsepower thanks to 5.5 liters of V-8 displacement and a Lysholm (or screw-type) belt-driven supercharger--a type that Mercedes says can achieve about 30 percent more charge pressure than other comparable belt-driven supercharging systems. The engine also features a crossflow air-to-water intercooler that reduces intake-air temperature for a denser charge. To reduce losses from the drag of the supercharger belt, the engine-management computer calculates whether to engage the supercharger depending on the engine speed and load. The system is designed to react instantly when the driver presses the accelerator pedal--an electromagnetic clutch engages the supercharger via its drive belt, providing immediate thrust even just off idle.

Shift Paddles (Audi & Mercedes)
Both of these sedans allow their drivers to shift using controls on the steering wheel. But they have different approaches. On the E55, the driver uses buttons mounted behind the top spokes of the wheel--press the left one for downshifts, the right button for upshifts. The RS 6, in contrast, uses paddles mounted slightly behind the wheel, more like the controls you'd find in a Formula One racer. With your hands resting lightly on the wheel, the paddles are in perfect position for your fingertips. You'll also find little rounded nibs on the paddles (like the dimples of a golf ball in reverse) that add a little additional friction--they feel nice to your fingers, too.

Dynamic Ride Control (Audi)
The RS 6 is the first Audi to offer DRC, an innovative new "active" suspension system that uses diagonally connected, hydraulically dampened shock absorbers to help maintain the overall stability of the car during hard cornering. By continually adjusting the hydraulic pressure at each shock absorber, DRC limits body roll and pitch during sporting maneuvers. DRC connects the shocks at the opposite corners of the vehicle via a hydraulic system incorporating a central reservoir. As the hydraulic pressure on the shock on the inside of a corner is reduced, hydraulic fluid is transferred through the reservoir to increase pressure to the diagonally linked shock on the outside of the corner. DRC also works to balance hydraulic pressure when either front or rear shocks are under pressure, such as during hard starts and stops.

Airmatic DC Computer-Controlled Air Suspension (Mercedes)
The E55 literally rides on air. Instead of conventional coil springs, the Mercedes Airmatic DC system uses compressed air in special rubber bellows in the spring struts. When the vehicle is moving, an electrically powered compressor charges the struts with compressed air via fast-acting solenoid valves; the valves regulate air volume and hence air pressure and the springing rate. Tailored specifically to AMG specifications, the system allows both a smooth, fluid ride and precise handling control. Under normal driving conditions, the entire air volume remains active to provide optimal comfort. When cornering at high speeds or during other sporting maneuvers, however, Airmatic briefly releases a portion of the air volume, resulting in a "stiffer" spring rate. Using a cockpit control, the driver can select from three damping rates--from super-comfy to sporty.