2020 Mercedes-AMG CLA 45: Compact Benz Is A Great Choice

• The 2020 Mercedes-AMG CLA 45 debuts the world's most powerful four-cylinder engine.
• The engine produces over 380 horsepower and accelerates to 60 mph in just four seconds.
• Expect the new Mercedes-AMG CLA 45 later this year, with prices close to that time.

The 2020 Mercedes-AMG CLA 45 is finally here. It's essentially a compact luxury sports car with the power and torque of a powerful car. It carries the same design language as the larger CLS, but no more than the C-Class. In short, it's a small little monster that packs a terrible punch. Over the next few minutes, we'll be taking a look at the new Mercedes-AMG CLA 45.

And that's only fitting, we start with the engine.

Mercedes-AMG M139 engine

The outgoing Mercedes-AMG CLA 45 is by no means a slow car. It arrived with an M133 engine producing 375 horsepower. However, if there is something not so good with the old engine, it is that it tends to dump all of its torque at lower engine speeds. Enter the new M139 engine. For starters, it's the most powerful production four-cylinder engine in the world. In the 2020 Mercedes-AMG CLA 45, the engine is good for 382 horsepower and 354 lb-ft. of torque, a reasonable jump from the previous output. That's a lot, to be honest, from a modest 2.0-liter four-cylinder engine.

Mercedes-AMG says the zero-to-60 time is just four seconds, and the top speed is electronically limited to 155 mph. The optional AMG Drivers Package bumps it up to 168mph (so order it). More importantly, the engine is tuned to behave like a naturally aspirated windmill. Peak torque hits 5,200 rpm, while Mercedes claims an instant boost of 1,000 to 2,000 rpm. And here's the bad news: The M139 engine is also available in S form with 415 horsepower and 369 lb-ft. torque. Sounds good, really, but this version is only available in the Mercedes-AMG CLA 45 S, which isn't coming to the US, by the way.

Why? We have no idea. But to be fair, 382 horsepower is still plentiful for what really is a small and compact Mercedes. But then again, is it really a Mercedes? America is all about horsepower. We can handle it.

The 2020 Mercedes-AMG CLA 45 uses a lightweight aluminum plate bolted under the engine. Known as the "cutting plate", it increases the torsional stiffness of the front end. Photo: MBUSA.

2020 Mercedes-AMG CLA 45: one person, one engine

It's not easy being the most powerful four-cylinder engine in the world. Mercedes had to develop a high-tech production line in Affalterbach to make this a reality. And since we're talking about an AMG engine and a production plant, every M139 factory is built using AMG's "One Man, One Engine" principle; This means the engine is built by hand and by one person from start to finish. Technicians use a variety of smart power tools that register every single application of torque. This allows technicians to build the engine with maximum precision while monitoring every step of the process.

Because if you're building the world's most powerful four-cylinder engine, you don't risk it with conventional hand tools.

With this method, AMG places the turbocharger and exhaust manifold at the rear of the engine (on the side wall of the firewall when viewed from the rear). The intake system is in front. Mercedes-AMG claims that this configuration creates the largest possible and most aerodynamically advantageous design for the front of the engine. In addition, the turbine housing is divided into two flow passages running parallel to each other. Divided channels in the exhaust manifold allow a separate flow of exhaust gases to the turbine. The design prevents the individual cylinders from negatively impacting each other during load cycles, which, according to Mercedes-AMG, helps boost torque.

Sounds like space age, but that's how Mercedes-AMG rolls around.

In addition to oil and water, air is directed to the turbocharger to keep it cool. The Mercedes-AMG CLA 45 also uses roller bearings on the compressor and turbine shafts to reduce mechanical friction. Photo: MBUSA.

Dual water pumps and dual injectors

An engine with high rotational speed and high power output usually requires the cooling capacity of a small nuclear generator. With this in mind, Mercedes-AMG provided the M139 engine with a set of two water pumps. The first is a high-performance mechanical block that supplies coolant to an aluminum cylinder head. The second is an electric water pump that works independently of the mechanical one. In fact, this pump continues to run even if the engine is turned off. This ensures that the crankcase is always cooled as efficiently and as quickly as possible.

The M139 engine uses two-stage fuel injection. During normal operation, the engine receives fuel from a set of piezo injectors operating at 2900 psi. If you really push it, the engine will engage a second set of fuel injectors (with solenoid valves) mounted in the intake manifold. The injectors operate at 97.2 psi and help the engine reach its maximum possible power.

Related: The Mercedes-AMG A 35 Sedan is the hot shoe nemesis for Audi and BMW.

2020 Mercedes-AMG CLA 45: powertrain technology

The 2020 Mercedes-AMG CLA 45 makes good use of the new eight-speed dual-clutch automatic. Power is sent to all four wheels via a fully variable 4MATIC+ all-wheel drive system. The transmission offers two distinct advantages. First, it is a rear-shift system that gives the rider the feeling of being pushed from behind. Further, the rear axle differential is equipped with AMG Torque Control. The latter means that the torque is not only distributed between the front and rear wheels, but it can also change the torque delivery between the left and right rear wheels.

The result of all this magic is consistent traction, whether on the street or on the racetrack. Best of all, drive torque is controlled by an electro-mechanical system that Mercedes claims is faster-responding and more advanced than a similar electro-hydraulic unit. This also means that the new Mercedes-AMG CLA 45 can be equipped with an optional Drift Mode. With this setup, all the power goes to the rear wheels, so you can do funny tail-sliding maneuvers in your compact luxury Mercedes-AMG.

2020 Mercedes-AMG CLA 45. Photo: MBUSA.

High performance everything

Without a doubt, the 2020 Mercedes-AMG CLA 45 is a small car, but highly efficient. It has a high performance engine, transmission and transmission, but it also needs a high performance suspension. Mercedes goes along with a four-link MacPherson strut strut design at the front and rear with three wishbones and a single trailing arm. The AMG Ride Control adaptive damping system is optional.