20 MPG combined. That’s the headline figure for the 2021 Mercedes-AMG C63 S Convertible, and let’s be honest, no one buying this snarling, sun-drenched performance machine is prioritizing fuel efficiency. This car exists to deliver a visceral experience, a symphony of V8 thunder and open-air thrills. The relatively low MPG figure is simply the price to enter a very exclusive club.

City and highway performance

The EPA estimates suggest 17 MPG in the city and 25 MPG on the highway. The city figure reflects stop-and-go traffic, where the C63 S Convertible’s potent 4.0L V8 is constantly battling its own immense gravitational pull to accelerate from one red light to the next. Highway performance is slightly better, but the temptation to exploit the engine’s prodigious power will inevitably drag that 25 MPG figure down. A lighter foot is crucial for achieving anything close to the EPA estimate on longer drives. The 9-speed automatic transmission, while excellent in its responsiveness, isn’t designed for ultimate hypermiling. It’s programmed for rapid shifts and maximizing the engine’s powerband.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2021 Mercedes-AMG C63 S Convertible is $2,900. This figure is based on driving 15,000 miles per year and using prevailing national average fuel prices. It’s important to remember that this is just an estimate. Your actual fuel costs will vary depending on your driving habits, local fuel prices, and the type of fuel you use, premium fuel is required, adding to the overall expense.

Real-world expectations

Forget the EPA numbers. If you’re consistently seeing anything above 15 MPG in mixed driving, consider yourself lucky. The sheer joy of unleashing the C63 S Convertible’s 503 horsepower and 516 lb-ft of torque will inevitably lead to spirited driving, which in turn, will tank your fuel economy. This car is an indulgence, and its fuel consumption reflects that. Owners are typically more concerned with the thrill of the drive than with saving a few dollars at the pump.

How it compares

Compared to its direct competitors, the C63 S Convertible’s fuel economy is par for the course. The BMW M4 Competition Convertible, with its inline-six engine, manages a similar 16 MPG city and 23 MPG highway. Audi’s RS5 Convertible, while employing a smaller V6, also lands in the same ballpark. Though a minor difference exists across these brands, these are not cars purchased with MPG in mind. For those considering the AMG brand, you can explore AMG MPG across all years. For a wider look at the brand, you can review all Mercedes Benz fuel economy data.

Tips to maximize efficiency

Resist the urge to constantly bury your right foot in the accelerator. The C63 S Convertible begs to be driven hard, but gentle acceleration and anticipatory driving techniques will significantly improve your fuel economy. Smooth, gradual inputs are key to minimizing fuel consumption.

Use the car’s various driving modes to your advantage. Comfort mode, while less engaging, will prioritize fuel efficiency by softening throttle response and optimizing shift points. It’s a sensible choice for mundane commutes or long highway stretches where performance isn’t a priority.

Ensure your tires are properly inflated to the recommended pressure. Underinflated tires increase rolling resistance, which negatively impacts fuel economy. Regular tire pressure checks are a simple but effective way to improve efficiency, as found in many cars in the AMG brand.

Avoid excessive idling. Modern engines are designed to be shut off when stationary for extended periods. Idling wastes fuel and contributes to unnecessary emissions. If you’re stopped for more than a minute, simply turn off the engine.

Consider the overall weight you’re carrying in the vehicle. Remove any unnecessary items from the trunk and passenger compartment. Excess weight puts additional strain on the engine, leading to increased fuel consumption. While this won’t make a huge difference, every little bit helps.