Daimler has recently announced the fact that the new generation 2012 Mercedes SLK 55 AMG will be offered with a new AMG, naturally-aspirated, 5.5-litre V8 engine.
This engine has been codenamed the M152 and it outputs 422 HP and 540 Nm (398 lb-ft) of torque. Based on the M157 plant which is also a 5.5-litre V8 but which uses two turbos, the M152 is 30 percent more efficient than the previous V8, and it now requires only 8.5-litres of fuel to cover 100 Km.
Also this new engine which will be fitted on the 2012 Mercedes SLK 55 AMG is made from aluminium, and it features the AMG Cylinder Management system, which basically means that it can shut off four cylinder and reduce the car’s torque level to 230 Nm. The switch from 8 cylinders to 4-cylinders takes no more than 30 milliseconds and it can be done from 800 rpm to 3,600 rpm.
We’ll have more details regarding this new engine and the 2012 Mercedes SLK 55 AMG once the car will premiere in Frankfurt this fall.

Source: Mercedes