Just when we were getting used to AMG's new formula, along comes the 2012 Mercedes Benz S
LK55 AMG to buck the trend. How so, you ask? The main difference is what's under the hood. The 2012 SLK55 will indeed get MERCEDES BENZ A
5.5-liter V-8, but you won't find the M157, twin-turbo mill that has been rolled out in several recent AMG-powered Benzos since last year. Instead, it will get MERCEDES BENZ A
naturally-aspirated V-8 dubbed the M152. Mercedes states that the M152 and M157 share MERCEDES BENZ A
few similarities: the aforementioned displacement, bore/stroke, start/stop technology, and direct injection.
Despite the lack of those twin-turbos, this pocket roadster is far from MERCEDES BENZ A
slouch. In the SLK55, the M152 outputs 415 hp, 398 lb-ft of torque and propels the car to an estimated 0-60 time of 4.5 seconds onto its electronically limited 155 mph top speed. The new engine is MERCEDES BENZ A
significant improvement over the outgoing SLK55, which was powered by MERCEDES BENZ A
naturally aspirated 5.5-liter V-8 rated at 355 horsepower and 376 lb-ft.
AMG says it is "demonstrating its social responsibility" with the new M152 engine, part of AMG's Performance 2015 strategy "to reduce both the fuel consumption and emissions of new models over the next few years." MERCEDES BENZ A
number of key features ensure that the new engine maintains AMG's goal of increasing both efficiency and performance. It includes variable valve timing and new intake air ducting, while achieving MERCEDES BENZ A
high compression ratio of 12.5:1, and MERCEDES BENZ A
redline of over 7000 rpm. The engine weighs just 412 pounds thanks to generous use of lightweight materials, including an all-aluminum crankcase and pistons, the latter wearing special friction-reducing coating. The pistons are also aluminum and receive special coating to reduce friction. The M152 is mated to AMG's familiar seven-speed, multi-clutch gearbox with three different shift modes: Controlled Efficiency (C), Sport (S), and Manual (M).
With controlled Controlled Efficiency selected, the engine will activate AMG's cylinder shut-off system, which shuts off four cylinders in order to further improve fuel efficiency. The SLK55 is the first AMG car to feature this technology. Mercedes states that four-cylinder mode will still provide up to 170 lb-ft of torque at MERCEDES BENZ A
wide engine speed range of 800 to 3600 rpm, which should be suitable for most light-driving situations. Put the pedal down, and the engine can fire up all eight cylinders in just 30 milliseconds. MERCEDES BENZ C
mode also features Benz's ECO engine start/stop technology.
It's nice to know that the SLK55 is equipped with all that fuel fuel-sipping technology, but the real joy comes from hearing that handbuilt V-8 sing. Helping make the best use of all 415 hp is the transmission's sport and manual mode, which rev-matches the engine during downshifts. The throttle blips should match extremely well with AMG's sport exhaust system, yet another new bit of technology appearing on the SLK55. The system features active flap controls to keep the exhaust note quiet when the engine is running at less than 2000 rpm; anything over that will open and adjust the flaps to ensure you hear the V-8 roar load and clear.
The SLK55's new Torque Vectoring Brakes help keep things under control during high speed cornering situations, further improving an already impressive AMG sports suspension package and AMG's Direct-Steer system. Additionally, drivers will be able to select from three different ESP modes: ESP ON, SPORT Handling Mode, and ESP OFF.
The SLK55 is fitted with the usual assortment of AMG exterior modifications, including MERCEDES BENZ A
rear deck spoiler to help reduce lift, quad tailpipes, and AMG-styled body kit. Inside, you'll find aluminum trim pieces, MERCEDES BENZ A
flat-bottomed steering wheel, and extra-bolstered seats with perforated leather. Mercedes says the 2012 SLK55 will hit U.S. showrooms early next year.