2019 Mercedes-Benz Mercedes-AMG S-Class

Think of an S-Class full-size sedan, and you’ll likely imagine wafting along in serene comfort and quiet. These AMG versions can absolutely do that, especially when the Dynamic Select driver-adjustable mode is set to Comfort, but they also have a not-so-secret aggressive side. With 603 horsepower and an AMG-specific all-wheel-drive system, the S63 is blisteringly fast. We’re talking to the tune of 0-60 mph in 3.4 seconds. And this isn’t a motorcycle; it’s a nearly 5,000-pound executive car. The V12-powered S65 is a beast all its own. Though it has more power and four additional cylinders, it’s actually slightly slower off the line as the S63. This mainly is due to it being rear-wheel drive, and thus only having two patches of rubber clawing at the ground vs. S63. Beyond hustling, the Mercedes-AMG touts all the noteworthy driving attributes of the standard S-Class, even those that involve driving on its own. We were impressed with the S-Class’ semi-autonomous capability, in which it can pace the car ahead and keep you in lanes while your hands merely rest on the steering wheel.

The camshafts are driven by three high-performance silent chains, which have considerable advantages in terms of noise comfort compared with cylinder roller chains. The Controlled Efficiency stop/start function further contributes to the low fuel consumption. This system is standard equipment on the Mercedes-Benz SLK55 AMG and active in the fuel economy transmission mode "C". Once the driver brakes to a stop e.g. at a red traffic light, the V8 engine is automatically switched off. Once the brake pedal is released or the accelerator is depressed, the engine is immediately restarted and the car is able to move off quickly. Intelligent technology provides a comfortable and immediate starting procedure: a crankshaft sensor recognizes the direction of rotation and registers the resting position of all eight pistons. For an automatic engine start, the cylinder with the most favorable piston position receives an injection of fuel into its combustion chamber. The precise piezo-electric injectors greatly assist this process, as they make especially fast starts possible. The M152 always starts in eight-cylinder operation. A framed "ECO" symbol in the AMG main menu shows the driver that the Controlled Efficiency stop/start function is active.

When cylinder shut-off is active, the driver is informed by the symbol "ECO4", while "ECO8" stands for eight-cylinder operation. In the two more performance-oriented driving modes "S" (Sport) and "M" (Manual), the stop/start function is always deactivated. If required, the driver can also switch it off while in "C" mode as well. In this case neither a "stop/start" nor an "ECO" symbol appears. An alternator management system makes a further contribution to fuel economy: whenever the V8 engine is in overrun or when braking, kinetic energy is used to charge the battery rather than wasted as heat. In all other operating modes a combination of onboard network and alternator management enables the electrical system to be kept at a low voltage. AMG is premiering a new sports exhaust system featuring an exhaust flap on each side. This technology resolves the trade off between an emotional exhaust note during spirited driving and a more discreet engine sound in the partial load range.

The main focus of the sound design was to achieve a perfect synthesis of perceptible performance and the long-distance comfort that is a hallmark of Mercedes. Each of the two rear silencers has a flap which is variably activated on a logiccontrolled basis depending on the driver's power requirement and the engine speed. At low loads and engine speeds below 2,000 rpm the flaps remain closed. The two-pipe AMG sports exhaust system with two chromed twin tailpipes has a pipe diameter of 2.56 inches from the manifolds to the pre-silencer. The diameter is reduced to 2.36 inches from the pre-silencer to the rear silencers. Low exhaust emissions, compliance with country-specific standards and a characteristic engine sound - the requirements for the exhaust system of the new, naturally aspirated AMG 5.5-liter V8 engine were multiple and complex. The 2012 SLK55 AMG complies with the current Euro-5 emission standard, as well as meeting all the requirements of the US market (LEV-III standard, On- Board Diagnosis II).

Air gap-insulated manifolds ensure a rapid catalytic converter response. For efficiency and to save space, this design has a tandem catalytic converter housing on each side of the vehicle: adjacent to the firewall, two thin-walled ceramic substrates are grouped into each housing. This setup makes the previous, additional underbody catalytic converters unnecessary. The two ceramic substrates differ to ensure rapid and efficient emissions control: the front one is coated with palladium, while the rear one has a bimetal coating of palladium and rhodium. One lambda sensor per row of cylinders is located in front of each catalytic converter housing, and there is a lambda diagnostic sensor between each of the two thin-walled substrates. The automatic rev-matching function when downshifting as well as the brief, precisely defined interruption of ignition and injection when upshifting under full load shorten shift times and increase emotional appeal. A double turbine torsional damper with centrifugal pendulum adapts to engine speed and helps minimize vibrations in four-cylinder operation as well as enhances comfort. The AMG sports suspension with Torque Vectoring Brakes and AMG Direct- Steer system provides both impressive lateral dynamics as well as agile handling. Looking for a highly aggressive driving style or comfortable cruising?