The 2012 Mercedes-Benz SLK55 AMG is the most powerful SLK of all time. Its new AMG 5.5-liter V8 engine featuring cylinder shutoff combines the ultimate in performance with the lowest possible fuel consumption. With a peak output of 415 hp and maximum torque of 398 lb-ft, the 2012 SLK55 AMG is poised to outperform all of its direct competitors. High-performance driving is ensured thanks to the AMG sports suspension with Direct-Steer system, Torque Vectoring Brakes and 3-stage ESP®, as well as the AMG high-performance braking system. The 2012 SLK55 AMG will arrive in U.S. showrooms in early 2012.
Forming part of the third-generation of the SLK launched in June, the new AMG model catches the eye at first glance: distinctive AMG light-alloy wheels, exclusive AMG body styling with AMG spoiler lip and two chrome-plated twin tailpipes at the rear complement the classic roadster proportions, while adding a distinct athletic touch. The expressive design of the 2012 SLK55 AMG is both eye-catching and unmistakable.
The SLK55 AMG is the perfect embodiment of the new AMG brand claim of "Driving Performance": in the compact high-performance Roadster segment there is nothing to compare to its combination of tangible driving dynamics, superior sportiness, unique high-technology and low fuel consumption. The SLK55 AMG accelerates from zero to 60 mph in 4.5 seconds, and reaches a top speed of 155 mph (electronically limited).
Key figures at a glance
2012 SLK55 AMG
Displacement 5,461 cc
Bore x stroke 3.86 in x 3.56 in
Compression ratio 12.6 : 1
Output 415 hp at 6,800 rpm
Max. torque 398 lb-ft at 4,500 rpm
Engine weight (dry) 412 lbs
Acceleration 0 - 60 mph 4.5 s
Top speed 155 mph**
* provisional figures; ** electronically limited
Helping to set new fuel efficiency standards for V8's, the 5.5 liter engine combines low consumption figures with superior power delivery and the typical exhaust growl which only a large-displacement eight-cylinder engine can produce.
In line with its "AMG Performance 2015" strategy, the new V8 engine continues to reduce both the fuel consumption and emissions of new models over the next few years - while reaching new heights with the central brand claim of "Driving Performance". At the same time, AMG is also demonstrating its social responsibility with the M152 engine.
New naturally aspirated eight-cylinder closely related to the V8 biturbo
The new M152 is based on the AMG M157 5.5-liter V8 biturbo engine presented in 2010, which powers the E63 AMG, CLS63 AMG, S63 AMG and CL63 AMG. Numerous design features are identical, such as the displacement, bore/stroke, distance between cylinders, ECO stop/start system and direct gasoline injection technology. Distinguishing features versus the M157 include the new intake air ducting, new cylinder heads, the modified valve drive, an adapted oil supply system and an optimized crankcase.
Exclusive combination of advanced technologies
The high-tech M152 motor dazzles with a combination of advanced technologies which is unequalled anywhere in the world. No other gasoline engine features direct injection at a pressure of 2,900 psi, spray-guided combustion and piezo injectors, all in conjunction with map-controlled cylinder shut-off, an all-aluminum crankcase with "spectacle" honing, fourvalve technology with continuous camshaft adjustment, a high compression ratio of 12.6 : 1, a stop/start system and generator management - while revving to a maximum speed of over 7,000 rpm. All of these features lead to high thermodynamic efficiency which is essential for high fuel efficiency and low exhaust emissions. Using a large-displacement, naturally-aspirated eight-cylinder engine with cylinder shut-off resolves the trade-off between high output/torque delivery and low fuel consumption figures.
AMG Cylinder Management
The AMG Cylinder Management cylinder shut-off system - developed completely by Mercedes-AMG - significantly improves efficiency: cylinders two, three, five and eight are cut off under partial load, which lowers fuel consumption considerably. In similar form, this technology is also used in the 750-hp V8 engines used in Formula 1. As efficiency also plays a major role at the pinnacle of motor racing, two or four of the eight cylinders are cut off e.g. when cornering at slow speed, during Safety Car laps or for pit stops.
The cylinder shut-off function is available over a wide engine speed range from 800 to 3,600 rpm if the driver has selected transmission mode "C" - Controlled Efficiency. The AMG main menu in the instrument cluster informs the driver whether cylinder shut-off is active, and whether the engine is currently running in four or eight-cylinder mode. No less than 170 lb-ft of torque is still available in four-cylinder mode - enough power to ensure plenty of acceleration in most driving situations. As soon as the driver has a need for more power and leaves the partial load range, cylinders two, three, five and eight are activated. The switch from four to eight-cylinder operation is immediate and imperceptible, leading to no loss of occupant comfort. At an engine speed of 3,600 rpm the activation process takes no more than 30 milliseconds.
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