The Mercedes-AMG CLA45 is a seriously quick four-door coupe positioned at the top of the CLA-Class lineup. Closely related to the GLA45 AMG, the CLA45 boasts the world's most powerful regular-production four-cylinder engine and a lightweight, purpose-designed all-wheel drive system.
For the latest model year, the CLA45 gains a more powerful engine that now develops 375 horsepower. The extra grunt is complemented by more standard equipment.
In the CLA45's engine bay lies a 2.0-liter four-cylinder engine that makes 375 horsepower at 6, 000 rpm and 350 lb-ft. of torque from 2, 250 to 5, 000 rpm thanks to a turbocharger and high-tech engineering such as multiple spark ignition and multiple injection. The mill sends the CLA45 from zero to 60 mph in 4.1 seconds and on to a top that is electronically limited to 155 mph.
Hand-built, the engine is linked to a seven-speed dual-clutch automatic transmission that sends power to all four wheels via a new 4Matic all-wheel drive system designed specifically to be used in cars with a transversally-mounted engine. It uses a power take-off unit that is built directly into the gearbox and cooled by its oil to transfer power to the rear wheels. By eliminating the need for a separate transfer case, the number of moving components drops and the total of weight of the system is reduced.
The engine's torque is distributed between the front and rear wheels by an electrohydraulically-activated multi-disk clutch that is integrated into the rear axle. Although part of a very complex system, it works in roughly the same way as a basic single-disk clutch. When the clutch is disengaged, the vehicle is primarily driven by the front wheels; when it is engaged, the rear wheels wake from their slumber and help move the car. Engaging and disengaging the clutch takes mere milliseconds.