The Mercedes-Benz CL63 AMG, the new AMG 5.5-liter biturbo engine combines performance, innovation and efficiency to a previously unknown extent. This is made possible by a unique combination of innovative high-tech systems such as direct gasoline injection, twin turbochargers, air/water intercooling and the Controlled Efficiency stop/start function.

The 2011 CL63 AMG develops a peak output of 536 hp and maximum torque of 590 lb-ft. In conjunction with the AMG Performance Package these figures increase to 563 hp and 664 lb-ft. The torque curve in particular shows that no other engine in this power class is able to match the figures delivered by the new AMG biturbo motor.

These improvements in efficiency and environmental protection have no negative effects on the car’s performance. On the contrary, as the new AMG 5.5-liter V8 biturbo fully lives-up to AMG’s brand commitment to “performance”: the Mercedes-Benz CL63 AMG accelerates from zero to 60mph in 4.4 seconds, and has a top speed of 155 mph (electronically limited). With the AMG Performance package, the highperformance Coupé reaches the 60 mph mark in 4.3 seconds and reaches a top speed of 186 mph (electronically limited).

Two turbochargers located next to the cylinder banks supply the eight cylinders with fresh air. At their maximum speed of 185,000 rpm under full load, the two turbochargers force 3,860 lbs into the combustion chambers per hour. The maximum charge pressure is 14.5 lbs, and 18.8 bar with the AMG Performance package. Thanks to their specific, compact construction – the turbine housings are welded to the exhaust manifold – there are significant space advantages and the catalytic converters also heat up more rapidly.

The new AMG V8 is the first turbocharged engine to dispense with the usual blow-off valve. This innovative solution enables the compressor housing to be made extremely compact. To ensure agile responsiveness with no time lag, all the air ducts in the intake tract are as short as possible. The wastegate valve, which reduces the pressure in the exhaust system during negative load changes, is vacuum-controlled via an electropneumatic converter. This allows dethrottling under partial loads, which in turn lowers the fuel consumption.

Like the existing AMG 6.0-litre V12 biturbo engine, the new eight-cylinder directinjection unit uses very efficient air/water intercooling. The low-temperature cooler with its water circulation is space-savingly accommodated within the V of the cylinder banks. It effectively cools down the intake air compressed by the turbochargers before it enters the combustion chambers, and maintains a constantly low intake temperature under full load. A large radiator at the car’s front end ensures metered cooling of the water circulating in the low-temperature circuit. This guarantees a high output and torque yield in all ambient temperatures and operating conditions.

Extremely short charge-air ducting makes for outstanding responsiveness. The stainless steel pressure pipes for the fresh and charge air are produced by the hydroforming process, have a wall thickness of only 0.03 inches and are designed for very low pressure loss.

The twin-pipe AMG sports exhaust system has a pipe cross-section of 2.76 inches from the manifolds to the rear silencers. When designing the sound, the aim was to create a perfect synthesis of aggressiveness and the comfort on long journeys that is the hallmark of a Mercedes. The goal of the developers was to achieve an emotional experience when accelerating and rev-matching, but unobtrusiveness at constant speeds. Unpleasant frequencies or droning noises were effectively eliminated during a series of painstaking tests. The sports exhaust system emits a sonorous eight-cylinder sound that is typical of AMG, while the striking chrome twin tailpipes feature a new design.