The Mercedes-Benz SLK 55 AMG represents the pinnacle of performance within the SLK roadster lineage. For the 2012 model year, Mercedes-AMG unleashed the most potent SLK to date, combining exhilarating power with surprising efficiency. This new iteration wasn’t just about raw speed; it was a sophisticated blend of high-performance engineering and innovative technology, designed to deliver an unparalleled driving experience. The heart of this beast is the all-new AMG 5.5-liter V8 engine, featuring groundbreaking cylinder shutoff technology, ensuring that the SLK 55 AMG stands out from the competition in terms of both power and responsible fuel consumption.
Unleashing Unrivaled Power and Performance
The Mercedes-Benz SLK 55 AMG is engineered for driving enthusiasts who demand uncompromising performance. Boasting a staggering 415 horsepower and 398 lb-ft of torque, this roadster is meticulously crafted to outperform its rivals. The AMG sports suspension, equipped with a Direct-Steer system, Torque Vectoring Brakes, and 3-stage ESP®, works in perfect harmony with the AMG high-performance braking system to deliver exceptional handling and control. This combination ensures that the SLK 55 AMG is equally at home carving through winding roads or cruising comfortably on the open highway.
Introduced as part of the third-generation SLK family, the Mercedes-Benz SLK 55 AMG immediately commands attention with its distinctive AMG styling. From the exclusive AMG light-alloy wheels to the assertive AMG body styling, complete with an AMG spoiler lip and dual chrome-plated twin tailpipes, every detail accentuates the roadster’s athletic and dynamic character. The expressive design of the SLK 55 AMG is both captivating and unmistakably AMG.
The Mercedes-Benz SLK 55 AMG perfectly embodies AMG’s “Driving Performance” philosophy. In the realm of compact high-performance roadsters, no other vehicle matches its unique blend of dynamic driving capabilities, superior sportiness, cutting-edge technology, and optimized fuel efficiency. The SLK 55 AMG catapults from 0 to 60 mph in a mere 4.5 seconds and reaches an electronically limited top speed of 155 mph, placing it firmly in the high-performance league.
| Specification | 2012 SLK55 AMG |
|---|---|
| Displacement | 5,461 cc |
| Bore x Stroke | 3.86 in x 3.56 in |
| Compression Ratio | 12.6 : 1 |
| Horsepower | 415 hp @ 6,800 rpm |
| Torque | 398 lb-ft @ 4,500 rpm |
| Engine Weight (dry) | 412 lbs |
| 0-60 mph Acceleration | 4.5 s |
| Top Speed | 155 mph (electronically limited) |
Setting New Standards in V8 Efficiency
The 5.5-liter engine within the Mercedes-Benz SLK 55 AMG redefines fuel efficiency expectations for V8 powertrains. It masterfully combines reduced fuel consumption with robust power delivery and the signature, thrilling exhaust note that only a large-displacement eight-cylinder engine can produce. This engine aligns perfectly with AMG’s “Performance 2015” strategy, aimed at progressively lowering fuel consumption and emissions in new models while simultaneously enhancing driving performance. The M152 engine in the SLK 55 AMG demonstrates AMG’s commitment to both driving pleasure and environmental responsibility.
This naturally aspirated eight-cylinder engine shares close ties with the V8 biturbo engine found in other high-performance AMG models. The M152 engine in the Mercedes-Benz SLK 55 AMG shares numerous design elements with the AMG M157 5.5-liter V8 biturbo, including displacement, bore/stroke, cylinder spacing, ECO stop/start system, and direct gasoline injection technology. Key differentiators include a redesigned intake air ducting, new cylinder heads, a modified valve drive, an adapted oil supply system, and an optimized crankcase, all tailored for the unique demands of a naturally aspirated, high-revving sports roadster.
Advanced Technologies for Peak Performance
The M152 engine in the Mercedes-Benz SLK 55 AMG is a showcase of cutting-edge automotive technology. Its suite of advanced features is unmatched in the industry. It boasts direct injection at an immense pressure of 2,900 psi, spray-guided combustion, and piezo injectors, all working in concert with map-controlled cylinder shut-off, an all-aluminum crankcase with “spectacle” honing, four-valve technology with continuous camshaft adjustment, a high compression ratio of 12.6:1, a stop/start system, and intelligent generator management. With a capability to rev beyond 7,000 rpm, these technologies coalesce to create exceptional thermodynamic efficiency, crucial for both fuel economy and minimizing emissions. The implementation of a large-displacement, naturally aspirated eight-cylinder engine with cylinder shut-off ingeniously resolves the traditional compromise between high power/torque and fuel efficiency.
AMG Cylinder Management: Intelligent Efficiency
The AMG Cylinder Management system, a Mercedes-AMG innovation, significantly boosts the efficiency of the Mercedes-Benz SLK 55 AMG. Under partial load, cylinders two, three, five, and eight are deactivated, dramatically reducing fuel consumption. This technology mirrors similar systems used in Formula 1 V8 engines, where efficiency is also paramount.
The cylinder shut-off system operates across a broad engine speed range, from 800 to 3,600 rpm, when the driver selects “C” (Controlled Efficiency) transmission mode. The AMG main menu within the instrument cluster provides real-time feedback, indicating whether cylinder shut-off is active and if the engine is running in four or eight-cylinder mode. Even in four-cylinder mode, a substantial 170 lb-ft of torque remains available, providing ample power for everyday driving scenarios. When the driver demands more power, the system seamlessly and instantaneously reactivates cylinders two, three, five, and eight. The transition between four and eight-cylinder operation is imperceptible, maintaining a smooth and comfortable driving experience. At 3,600 rpm, the activation process is completed in a mere 30 milliseconds.
This sophisticated cylinder shut-off is achieved via an intelligent engine management system, featuring 16 hydraulically compensating actuators and an advanced oil supply system within the cylinder head. These actuators, integrated into the cylinder head, keep the intake and exhaust valves of the designated cylinders closed during shut-off, while also deactivating their fuel supply and ignition. This reduces load-change losses and enhances the efficiency of the remaining active cylinders by shifting their operating point to a higher load range. The compact and lightweight design of the actuators allows for precise valve train operation and supports engine speeds up to 7,200 rpm.
Advanced Engine Components and Efficiency Measures
The crankcase of the AMG 5.5-liter V8 engine in the Mercedes-Benz SLK 55 AMG is constructed from diecast all-aluminum, contributing to a low dry engine weight of just 412 lbs through meticulous lightweight design. Key features include grey cast iron bearing covers for the main crankshaft bearings, bolted to the crankcase for enhanced rigidity. Carbon-coated piston rings minimize internal friction and wear, while cast-in Silitec cylinder liners further reduce friction for the pistons.
“Spectacle” honing, a unique and complex process, mechanically treats the cylinder liners after they are bolted in place, eliminating static distortion caused by cylinder head bolt tightening and further reducing friction. Additional efficiency-enhancing measures include:
- Weight-optimized cast aluminum pistons with special piston skirt coating
- Special ventilation holes in the crankcase
- Oil pump with electrically controlled pressure stage
- Separate oil pump for cylinder shut-off
- Efficient cross-flow engine cooling
- Electronically controlled fuel pressure (1,450 to 2,900 psi)
The forged crankshaft, crafted from high-grade 38MnS6BY steel alloy, rotates on five main bearings and is optimized for torsional rigidity, inertia, and low rotating masses. A two-mass viscous damper effectively eliminates vibrations. Forged, cracked connecting rods are utilized for each connecting rod journal on the crankshaft.
Four-Valve Technology and Variable Camshaft Adjustment
Optimal combustion chamber charging in the Mercedes-Benz SLK 55 AMG is ensured by large intake and exhaust valves, four per cylinder. Sodium-cooled hollow exhaust valves manage high thermal loads. Four overhead camshafts operate the 32 valves via low-friction cam followers. Infinitely variable camshaft adjustment across a 40-degree range on both intake and exhaust sides adapts to engine load and speed, optimizing output and torque while ensuring consistent idling. Valve overlap is variably adjusted to maximize fuel/air supply and exhaust gas removal. Hydraulic pivoting actuators, electromagnetically activated and ECU-controlled, manage camshaft adjustment. Silent chains drive the camshafts, enhancing noise comfort compared to roller chains.
Controlled Efficiency Stop/Start Function
The Controlled Efficiency stop/start function further reduces fuel consumption in the Mercedes-Benz SLK 55 AMG. Standard and active in “C” mode, it automatically shuts off the V8 engine when the vehicle stops, such as at traffic lights. Releasing the brake or pressing the accelerator instantly restarts the engine. Intelligent technology ensures a smooth restart: a crankshaft sensor detects rotation direction and piston positions, injecting fuel into the cylinder with the most favorable position for immediate start-up. The M152 engine always restarts in eight-cylinder mode.
An “ECO” symbol in the AMG main menu indicates stop/start function activity, with “ECO4” signifying four-cylinder operation and “ECO8” indicating eight-cylinder mode. The stop/start function is deactivated in “S” (Sport) and “M” (Manual) modes but can be manually switched off in “C” mode if desired.
Alternator Management for Enhanced Fuel Economy
An alternator management system in the Mercedes-Benz SLK 55 AMG further contributes to fuel efficiency by using kinetic energy during overrun or braking to charge the battery, rather than wasting it as heat. In other modes, the system maintains a low voltage in the electrical system.
AMG Sports Exhaust System with Integrated Exhaust Flaps
The Mercedes-Benz SLK 55 AMG debuts a new AMG sports exhaust system with exhaust flaps on each side, balancing emotional sound during spirited driving with a more refined engine note at partial load. The system is designed to provide a perfect blend of performance audibility and Mercedes-Benz long-distance comfort.
Each rear silencer features a flap variably activated based on driver input and engine speed. Below 2,000 rpm and at low loads, flaps remain closed, routing exhaust gases through a longer path and additional damping, resulting in a subdued and mellow tone, particularly noticeable in four-cylinder operation. During acceleration, flaps progressively open, starting at 15 degrees and increasing to 50 degrees, allowing exhaust gases to take a shorter path, producing a sonorous engine note. At full load and higher engine speeds in eight-cylinder mode, both flaps fully open, unleashing the characteristic muscular sound of an AMG V8, emphasizing the 415 hp engine’s performance.
The two-pipe AMG sports exhaust system features chromed twin tailpipes and pipe diameters optimized for both sound and performance.
Advanced Emissions Technology
The exhaust system of the Mercedes-Benz SLK 55 AMG meets stringent Euro-5 emission standards and US market requirements (LEV-III, On-Board Diagnosis II). Air gap-insulated manifolds ensure rapid catalytic converter response. Tandem catalytic converter housings, located close to the firewall, integrate two thin-walled ceramic substrates each, eliminating the need for underbody catalytic converters. The substrates are specifically coated for efficient emissions control: palladium for the front and a bimetal palladium-rhodium coating for the rear. Lambda sensors are strategically placed for precise emissions monitoring.
AMG SPEEDSHIFT PLUS 7G-TRONIC Transmission
Power in the Mercedes-Benz SLK 55 AMG is delivered to the rear wheels via the AMG SPEEDSHIFT PLUS 7G-TRONIC automatic transmission. It offers three modes: “Controlled Efficiency” (C), Sport (S), and Manual (M). Automatic rev-matching during downshifts and brief ignition/injection interruption during upshifts enhance shift times and driving excitement. A double turbine torsional damper with centrifugal pendulum adapts to engine speed, minimizing vibrations, especially in four-cylinder mode, and improving overall comfort.
Dynamic Handling and Comfortable Cruising
The AMG sports suspension, coupled with Torque Vectoring Brakes and AMG Direct-Steer, provides the Mercedes-Benz SLK 55 AMG with both exceptional lateral dynamics and agile handling. Whether the driver seeks aggressive cornering or relaxed cruising, the SLK 55 AMG adapts seamlessly. Independent suspension struts with stiffer spring/damper tuning, torque strut bearings on the front axle, stiffer stabilizers, and increased negative camber on the rear axle result in high cornering speeds and reduced body roll.
Torque Vectoring Brakes enhance cornering by applying selective braking to the inside rear wheel, inducing precise turn-in. The AMG Direct-Steer system improves handling and agility while reducing parking effort. A new power steering pump enhances fuel efficiency by operating only when steering input is detected. The AMG Direct-Steer system’s parameters are specifically tuned to complement the AMG sports suspension, providing optimal responsiveness, road feel, and sharp handling in all driving conditions.
The AMG-exclusive 3-stage ESP® offers customizable control with “ESP ON,” “SPORT Handling Mode,” and “ESP OFF” settings. The AMG high-performance braking system features ventilated and perforated discs for exceptional responsiveness, short stopping distances, and fade resistance.
For even greater driving dynamics, the optional AMG Handling Package includes an AMG Performance suspension, rear axle differential lock, two-piece front brake discs, and an AMG Performance steering wheel.
Striking AMG Design and Premium Appointments
The Mercedes-Benz SLK 55 AMG boasts classic roadster proportions enhanced with distinctive AMG design cues and inspiration from the SLS AMG. The AMG-designed front apron features large air inlets and AMG-specific LED daytime running lights. The wide radiator grille, reminiscent of the SLS AMG, prominently displays a central Mercedes star. High-gloss black finishes accent the front apron, while darkened headlamps and bicolor tail lamps are exclusive to the V8 model. Optional Bi-Xenon headlights with Active Curve Illumination are available.
Vent grilles in the front fenders, with chrome-plated fins, echo both the SLS AMG and the iconic Mercedes-Benz 300 SL Roadster. “V8 AMG” lettering highlights the top-tier model. AMG-specific side sill panels and a unique rear apron with a black diffuser insert and AMG sports exhaust system complete the exterior enhancements. A body-colored spoiler lip on the trunk lid reduces rear axle lift at high speeds.
The interior of the Mercedes-Benz SLK 55 AMG mirrors the SLS AMG Roadster with jet engine-inspired air vents and a brushed aluminum center console. An AMG-specific analog clock by IWC adds a touch of luxury. The AMG Performance steering wheel features a flattened shape, metal trim, aluminum shift paddles, and perforated leather grip areas. The AMG instrument cluster is clearly arranged with four circular instruments and an AMG main menu.
AMG sports seats offer enhanced lateral support, premium leather upholstery with AMG badges, and standard AIRSCARF neck-level heating.
MAGIC SKY CONTROL Panorama Roof
The Mercedes-Benz SLK 55 AMG features a retractable hardtop that transforms the roadster into a coupe in under 20 seconds. Optional panorama roof panels in tinted polycarbonate are available, as is the innovative MAGIC SKY CONTROL panorama roof. This glass roof switches between light and dark at the touch of a button, offering an open-air feel even in cold weather and shading the interior in bright sunlight. Magnesium frames for all roof variants reduce weight and lower the car’s center of gravity. The AIRGUIDE pivoting wind-stop offers a comfortable alternative to traditional wind deflectors.
Advanced Safety and Assistance Systems
The Mercedes-Benz SLK 55 AMG sets new safety standards with a suite of advanced assistance systems. Standard features include fiber-reinforced roll-over bars, multi-stage airbags, NECK-PRO head restraints, three-stage ESP®, and ATTENTION ASSIST. Optional systems include DISTRONIC PLUS proximity control and PRE-SAFE® Brake for collision mitigation.
The Legacy of SLK AMG
The 2012 Mercedes-Benz SLK 55 AMG represents the third generation of AMG’s dynamic roadster. The lineage began in 2001 with the SLK32 AMG, featuring a supercharged V6 engine. In 2004, the SLK55 AMG debuted with a naturally aspirated V8, continuing AMG’s commitment to high-performance roadsters with powerful engines. The 2012 Mercedes-Benz SLK 55 AMG carries this legacy forward, delivering unmatched performance and innovation in its class.
