21 MPG combined is a figure unlikely to sway anyone considering the 2021 Mercedes-Benz AMG C63 S. This isn’t a car bought for its low gas consumption, but rather for its ferocious performance and emotive soundtrack, courtesy of a hand-built 4.0L twin-turbo V8. The C63 S buyer is after an experience, a visceral thrill, and they’re willing to pay at the pump for it.

City and highway performance

The C63 S reflects its dual nature in its city and highway MPG figures. City driving, where the engine is constantly accelerating and decelerating, yields 17 MPG. This reflects the engine’s inherent thirst and the temptation to exploit its readily available power. On the open road, the C63 S fares somewhat better, achieving 26 MPG.

This improvement is thanks to the engine operating more consistently within its optimal range, aided by the smooth-shifting 9-speed automatic transmission. However, even on the highway, aggressive driving will quickly negate any potential fuel savings.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2021 Mercedes-Benz AMG C63 S is $2,750. This figure is based on driving 15,000 miles per year, with a specified percentage of those miles driven in the city versus on the highway, and using national average fuel prices. Premium fuel is required to realize optimal efficiency and performance with this engine.

It’s a significant sum, and one of the highest among performance sedans, but it’s a price most C63 S owners are prepared to pay for the performance and prestige the car delivers.

Real-world expectations

While the EPA provides a standardized estimate, real-world fuel economy can vary significantly based on driving style and conditions. Aggressive acceleration, frequent hard braking, and sustained high speeds will all drastically reduce fuel economy. A more conservative approach, using a light foot and anticipating traffic flow, can help to achieve figures closer to the EPA estimates.

However, resisting the urge to unleash the V8’s full potential is a challenge for any C63 S owner.

How it compares

The main competitor regarding performance sedans is usually BMW’s M3. The M3 Competition, with its 3.0L inline-six, manages a combined 19 MPG. The Audi RS5 Sportback, with its 2.9L twin-turbo V6, achieves a slightly better 21 MPG combined. The Cadillac CT5-V Blackwing, boasting a supercharged 6.2L V8, matches the C63 S at 17 MPG city and 26 MPG highway.

For C63 S buyers, these differences are usually overshadowed by brand loyalty and styling preferences above pure MPG.

Explore all Mercedes Benz fuel economy data, or dive into AMG MPG across all years to understand how this model fits into the broader landscape of performance vehicles.

Tips to maximize efficiency

Avoid aggressive acceleration and braking. The C63 S’s prodigious torque output makes it tempting to accelerate hard from every stop. However, gentle acceleration allows the engine to operate more efficiently, saving fuel in the process. Anticipate traffic flow and avoid unnecessary hard braking, which wastes energy and fuel.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, which reduces fuel economy. Check tire pressures regularly and inflate them to the recommended levels specified on the door jamb placard. This small step can make a noticeable difference over time.

Minimize idling. Letting the engine idle for extended periods wastes fuel. If you anticipate being stopped for more than a minute, consider turning off the engine. Modern vehicles are designed to restart quickly and efficiently, saving fuel and reducing emissions.

Use cruise control on the highway. Maintaining a constant speed on the highway minimizes fluctuations in engine load, leading to improved fuel economy. Use cruise control whenever possible, especially on long drives, to optimize fuel consumption.

Consider using a lighter wheel and tire package when it’s time for replacements. Lower unsprung weight can improve fuel economy and handling.