Mercedes-AMG’s Flat-Plane V8 Mythos Is Being Built To Ruin The BMW M4

Key Takeaways

• The Mercedes-AMG CLE 63 Mythos has been spotted testing with a substantially revised hood featuring a large air intake above the engine bay.
• The new intake appears to be part of AMG’s ongoing effort to improve cooling and airflow as development of the limited-production coupe continues.
• The CLE 63 Mythos is expected to use an AMG-developed version of Mercedes-AMG’s new twin-turbocharged 4.0-liter V8 with a flat-plane crankshaft.
• Current reports suggest the Mythos could produce roughly 637 to 646 hp, although Mercedes-AMG has not confirmed the final output.
• AMG is reportedly targeting significant weight savings and serious track capability rather than simply adding power to the CLE platform.
• Production is not expected before 2027, and the Mythos is expected to be built in strictly limited numbers.

Mercedes-AMG CLE 63 Mythos Gets a New Hood Intake

The Mercedes-AMG CLE 63 Mythos is still undergoing development, and the latest prototype suggests AMG is making some important changes to the car’s cooling and aerodynamic package. A heavily camouflaged prototype has been spotted testing in Germany with a large new opening in the hood, along with several other revisions that distinguish it from earlier development cars.

The new hood intake is one of the most obvious changes. Earlier CLE 63 Mythos prototypes featured a conventional hood, while the latest test car has a substantial opening positioned directly above the engine compartment. The design strongly suggests that managing heat and airflow has become a major priority during development of AMG’s most extreme CLE.

The change is particularly interesting because the Mythos is expected to use a high-output version of AMG’s latest 4.0-liter twin-turbocharged V8. Mercedes-AMG has already introduced the updated M177 EVO V8 with a flat-plane crankshaft in other performance models. The company says the new crankshaft reduces rotating mass, improves the engine’s ability to rev and delivers more precise response. Mercedes-AMG’s official M177 EVO announcement

For the CLE 63 Mythos, that engine is expected to be tuned considerably beyond the 612-hp version currently offered in the GLE 63 S and GLS 63. Reports indicate that the Mythos could produce approximately 637 to 646 hp, putting it in a completely different performance category from the existing six-cylinder CLE 53.

Why Does the CLE 63 Mythos Need More Cooling?

The hood intake appears to be more than a styling exercise. A high-performance turbocharged V8 generates substantial heat, particularly when the engine is subjected to repeated high-load operation on a race track. The CLE 63 Mythos is reportedly being developed with serious track use in mind, making thermal management especially important.

The prototype has also been photographed without a front license plate. While the absence of a plate may simply be a development configuration, it also leaves the central front area unobstructed and can allow engineers to maximize airflow while testing the car’s cooling system. A front license plate is required for road use in Germany, so the test configuration should not be interpreted as an indication of the final production specification.

Reports from the latest prototype testing claim that the hood redesign follows an engine failure during the development program. That specific detail has not been independently confirmed by Mercedes-AMG, so it should be treated as a report rather than established fact. Regardless of what prompted the change, the new intake demonstrates that AMG is continuing to modify the car rather than simply moving an existing prototype toward production unchanged.

That is significant for a car like the Mythos. Limited-production performance models are often developed around a much narrower set of priorities than regular production vehicles. AMG can afford to use more aggressive aerodynamic solutions and specialized cooling hardware because the Mythos is not intended to serve as a high-volume model.

More Than Just a Powerful CLE 63

The CLE 63 Mythos is shaping up to be substantially different from the regular AMG CLE range. The standard CLE 53 is already a serious performance coupe, but its 3.0-liter turbocharged inline-six produces 449 hp and uses mild-hybrid assistance. Mercedes-AMG says the CLE 53 can accelerate from 0 to 100 km/h in 4.2 seconds with its standard AMG Performance 4MATIC+ all-wheel-drive system. Mercedes-AMG’s official CLE 53 specifications

The Mythos takes a very different approach. Instead of focusing primarily on everyday usability, AMG is reportedly working toward a substantially lighter and more aggressive car with greater aerodynamic performance and stronger track credentials.

Spy photographs have already revealed a dramatic body kit. The prototype features large openings around the front end, vents near the headlights, aggressive outlets in the front fenders, widened rear arches and a substantial front splitter. At the rear, the car uses a large adjustable wing mounted on prominent supports, while four exhaust outlets are arranged in a distinctive diagonal layout.

These features are not simply visual upgrades. Large openings can provide additional airflow for the engine and brakes, while the enlarged bodywork can accommodate wider wheels and tires. The rear wing and front splitter can also generate additional aerodynamic load at speed, giving the chassis more stability during hard cornering.

That focus on aerodynamic performance helps explain why the latest prototype is being tested with so many different airflow-related changes. AMG needs the production car to maintain appropriate temperatures while generating enough aerodynamic performance to meet its handling targets.

The Flat-Plane V8 Is the Heart of the Mythos

The most important mechanical component of the CLE 63 Mythos is expected to be its flat-plane V8. Mercedes-AMG has taken its existing 4.0-liter twin-turbo V8 architecture and made substantial changes for the latest generation, including the adoption of a flat-plane crankshaft.

A flat-plane crankshaft differs from the cross-plane crankshaft traditionally used in AMG’s V8 engines. The configuration allows the crankshaft to have a different firing arrangement and reduces rotating mass. AMG says its new design improves response and revving ability while helping deliver more precise power delivery.

AMG has previous experience with flat-plane V8 technology. The Mercedes-AMG GT Black Series used a specially developed 4.0-liter V8 with a flat-plane crankshaft and produced 730 PS. Mercedes-AMG explained at the time that the lighter crankshaft and revised firing order were intended to improve response, gas exchange and high-rpm performance.

The new M177 EVO takes that concept into a newer generation of AMG powertrains. In the GLE 63 S and GLS 63, the updated engine produces 612 hp and 850 Nm of torque. The engine also incorporates revised intake and exhaust ports, an updated intake camshaft, optimized fuel injection and improvements to the turbocharger hardware.

The Mythos should receive its own calibration and hardware changes. Although AMG has not released final specifications, reports of approximately 637 to 646 hp would give the coupe a substantial increase over the 449-hp CLE 53.

More importantly, the Mythos is expected to extract more performance from the V8 through its overall vehicle engineering rather than relying exclusively on peak horsepower. Weight, cooling, suspension tuning, brakes, tires and aerodynamics should all play a major role in determining how quickly the car can perform on a circuit.

Weight Reduction Could Be Just as Important as Power

The CLE 63 Mythos is reportedly being developed with significant weight reduction in mind. AMG has not yet released a production curb weight, but reducing mass would be especially important for a model designed to deliver serious track performance.

Lower weight benefits almost every aspect of a performance car. A lighter vehicle can brake harder, change direction more quickly and place less stress on its tires and brakes. It can also improve acceleration without requiring additional engine output.

The prototype’s carbon-fiber roof is another indication of AMG’s approach. Recent test cars have provided a clearer look at the roof, which features a distinctive central depression. Carbon fiber and other lightweight materials could help reduce mass higher up in the vehicle, lowering the center of gravity and improving handling response.

That philosophy is consistent with the positioning of the Mythos family. Mercedes-Benz introduced Mythos as a range for highly exclusive, limited-production vehicles positioned above the company’s regular model lines. The goal is not to create another trim level but to produce special vehicles with a stronger emphasis on design, performance and exclusivity.

Will the CLE 63 Mythos Rival the BMW M4?

The BMW M4 is an obvious reference point for any high-performance coupe based on the CLE platform, but the Mythos is expected to occupy a more extreme position. Its combination of V8 power, aggressive aerodynamics and limited production should separate it from conventional sports coupes.

Mercedes-AMG is also reportedly developing a more accessible V8-powered 63-badged CLE that would make a more direct challenge to the BMW M4. The Mythos, by comparison, is intended to sit at the top of the performance hierarchy.

That distinction matters because the Mythos is not expected to compete primarily on practicality or price. Buyers will instead be paying for specialized engineering, limited availability and a level of performance that would be difficult to justify in a regular production model.

The aggressive aerodynamic package also suggests that AMG wants the Mythos to have a much stronger track presence than a conventional CLE 63. The large rear wing, enlarged fenders, front splitter and numerous cooling openings are all consistent with a car designed to remain stable and thermally controlled during repeated high-speed laps.

When Will the Mercedes-AMG CLE 63 Mythos Arrive?

The latest prototype indicates that development is still underway, and production is reportedly not expected to begin before 2027. AMG still has time to finalize the cooling system, aerodynamic package, engine calibration, chassis setup and other components before production begins.

The final specifications could therefore differ from the figures currently circulating. The estimated 637 to 646 hp output has not been confirmed by Mercedes-AMG, and the company has not announced final performance figures, pricing or production volume for the CLE 63 Mythos.

Production is expected to be strictly limited, following the strategy already established for Mercedes-Benz Mythos models. That limited availability will likely make the CLE 63 Mythos considerably more expensive than the standard AMG CLE range.

The car’s development also shows that AMG is not treating the Mythos simply as a cosmetic special edition. The new hood intake, extensive aerodynamic hardware, expected weight-saving measures and flat-plane V8 point toward a comprehensive performance program.

If the reported specifications hold, the Mercedes-AMG CLE 63 Mythos could become one of the most serious road-legal performance coupes in AMG’s current lineup. Its importance also extends beyond the car itself, because the flat-plane V8 technology is expected to spread to additional AMG models after the Mythos arrives.

Frequently Asked Questions

What engine will the Mercedes-AMG CLE 63 Mythos use?

The CLE 63 Mythos is expected to use an AMG-developed version of Mercedes-AMG’s 4.0-liter twin-turbocharged V8 with a flat-plane crankshaft. The latest M177 EVO engine already uses a flat-plane crankshaft and produces 612 hp in the current GLE 63 S and GLS 63.

How much horsepower will the CLE 63 Mythos have?

Current reports indicate approximately 637 to 646 hp. Mercedes-AMG has not yet confirmed the final horsepower rating, so the reported figure should be considered an estimate until official specifications are released.

Why does the Mercedes-AMG CLE 63 Mythos have a hood intake?

The large hood intake appears to be intended to improve airflow and cooling around the engine compartment. The Mythos is expected to use a high-output V8 and is being developed with serious track performance in mind, making thermal management particularly important.

Will the CLE 63 Mythos be faster than the CLE 53?

The Mythos is expected to be substantially more powerful than the CLE 53. The CLE 53 produces 449 hp from its 3.0-liter turbocharged inline-six, while the Mythos is expected to use a V8 producing more than 630 hp.

When will the Mercedes-AMG CLE 63 Mythos go into production?

Production is reportedly not expected to begin before 2027. Mercedes-AMG has not yet announced an official production start date.

How many CLE 63 Mythos models will be built?

Production is expected to be strictly limited, but Mercedes-AMG has not announced the final production volume. The Mythos name is reserved for highly exclusive models positioned above AMG’s regular lineup.

Will the CLE 63 Mythos use a flat-plane crankshaft?

Yes, the car is expected to use an AMG-developed version of the new flat-plane-crank 4.0-liter V8. Mercedes-AMG says the flat-plane design reduces rotating mass, improves revving ability and provides more precise engine response.