2021 BMW M8 Competition Convertible Fuel Economy: What To Expect

17 MPG combined is what you’ll get for driving the 2021 BMW M8 Competition Convertible. It’s the thermodynamic tax you pay to experience 617 horsepower, a soundtrack that borders on obscene, and open-air motoring in a package that can legitimately frighten supercars. This isn’t a car bought for sensible commuting or hypermiling contests; it’s for making explosive entrances and feeling the wind in what’s left of your hair.

City and highway performance

The EPA estimates suggest 15 MPG in the city and 21 MPG on the highway. The city figure reflects the M8’s tendency to unleash its twin-turbocharged fury even in mundane stop-and-go traffic. The throttle is sensitive, the temptation immense, and the result predictable. The highway figure is slightly more palatable. If you resist exploring the upper reaches of the speedometer, you’ll get closer to the advertised number. The eight-speed automatic transmission (S8) does its best to optimize fuel consumption, but its primary mission is rapid-fire gear changes, not economy.

Annual fuel cost

The EPA estimates an annual fuel cost of $3,400 for the M8 Competition Convertible, assuming 15,000 miles driven per year and current national average fuel prices. This hefty sum underscores the financial commitment involved in owning a high-performance machine. Remember, this figure is calculated using premium fuel, which is mandatory for optimal performance and longevity. Skimping on fuel grade is a false economy in a car of this caliber.

Real-world expectations

Don’t expect to consistently achieve the EPA’s figures. Many drivers who embrace the car’s performance capabilities will likely see numbers closer to the low teens in mixed driving. Spirited acceleration, frequent use of Sport and Sport+ modes, and simply enjoying the rumble of the exhaust will all negatively impact fuel economy. The M8 Competition Convertible is not a machine that encourages restraint. Understanding this will prevent disappointment. Think of the fuel gauge as a real-time indicator of enjoyment rather than efficiency. For a broader view, check M8 MPG across all years.

How it compares

The M8 Competition Convertible exists in a rarefied segment where fuel economy is rarely a primary concern. Still, context matters. A Porsche 911 Turbo S Cabriolet, while similarly priced and performing, can achieve around 17 MPG combined in real-world testing, which is a touch better, but still thirsty. An Aston Martin Vantage Roadster, another competitor, posts figures in the same ballpark. The Mercedes-AMG SL63 offers comparable performance and prestige and lands in about the same fuel economy range. The slight variations in MPG are unlikely to sway a buyer in this segment because the differences are largely negligible compared to the cars’ other performance and luxury attributes. Consider looking at all BMW fuel economy data for a broader comparison across the brand.

Tips to maximize efficiency

Resist the urge to bury the accelerator every time the light turns green. Smooth and deliberate inputs can dramatically reduce fuel consumption, especially in city driving. The M8’s engine produces immense torque even at low RPM, so taking it easy off the line won’t sacrifice much actual progress.

Use the adaptive cruise control system on long highway drives. Maintaining a consistent speed not only reduces driver fatigue but also minimizes unnecessary acceleration and braking, which can significantly improve fuel economy. Let the car manage the throttle for a change, and watch the MPG climb, relatively speaking.

Check the tire pressure regularly. Properly inflated tires reduce rolling resistance, which can positively impact fuel economy. Refer to the sticker on the driver’s side doorjamb for the recommended tire pressure specifications.

Consider using the Comfort driving mode for mundane commutes. While it may not offer the same level of excitement as Sport or Sport+, Comfort mode softens the throttle response and adjusts the transmission mapping for smoother, more efficient operation. Save the aggressive modes for when you truly want to unleash the car’s potential.

Avoid excessive idling. If you’re stopped for more than a minute or two, turn off the engine. Modern engines are designed to restart quickly and efficiently, and idling simply wastes fuel. Start-stop is often misunderstood; don’t fall for the misconception that restarting the engine wastes gas.