17 MPG combined is the reality for anyone considering the 2020 BMW M8 Competition Convertible with its reliable 4.4L V8. Fuel economy is not the primary concern for buyers of this car. This is a high-performance statement piece, a machine engineered for exhilarating speed and open-air thrills. The M8 Competition Convertible is bought by those who can afford the price of entry, and also the price at the pump.

City and highway performance

The EPA estimates 15 MPG in the city and 21 MPG on the highway for this version of the M8. The city figure reflects the engine’s thirst when subjected to stop-and-go traffic and frequent bursts of acceleration. The highway number isn’t terrible, but achieving it requires restraint. The M8’s prodigious power is always available, and using it, which the car encourages, will quickly send your highway MPG plummeting. The automatic transmission, tuned for both track performance and daily driving, helps in delivering the best possible fuel efficiency when left to its own devices, but it’s only capable of so much when paired with a high-output V8.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2020 BMW M8 Competition Convertible will be $3,400. This figure is based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway. It also assumes the use of the national average fuel price prevailing at the time of the EPA’s testing. Real-world fuel costs may vary depending on driving habits and local fuel prices. How often the M8’s performance potential is unleashed also matters. Most M8 drivers will meet or exceed that $3,400 figure, especially considering premium fuel is mandatory.

Real-world expectations

EPA figures provide a standardized baseline, but real-world fuel economy will depend heavily on driving style. Someone who frequently engages the M8’s launch control or spends most of their time in Sport or Sport+ mode will likely see figures significantly lower than the EPA estimates. A driver who primarily uses the M8 for longer highway cruises and adopts a more relaxed driving style might achieve numbers closer to, or even slightly above, the 21 MPG highway estimate. The M8 badge implies a certain spiritedness behind the wheel, so don’t be surprised if your lifetime average lands closer to 14 MPG than 17.

How it compares

Compared to other high-performance convertibles, the M8’s fuel economy is within the expected range. The Mercedes-AMG SL63, with its similar displacement V8, achieves comparable numbers in real-world testing. The Porsche 911 Turbo S Cabriolet boasts slightly better fuel economy at around 18 MPG combined, but it still demands premium fuel. It’s ultimately purchased for its performance capabilities, not its frugality. All Bmw fuel economy data shows the M8 is on the lower end of the brand’s efficiency spectrum, a clear indication of its performance-oriented design. Buyers prioritizing fuel efficiency, even in a premium package, look at models like the Bmw 530e plug-in hybrid. For more information on the M8’s broader market fit, browse M8 MPG across all years and configurations.

Tips to maximize efficiency

Use the Adaptive drive mode for everyday commuting. This setting optimizes the engine and transmission for efficiency while still providing responsive performance when needed. Avoid constantly hammering the throttle; smooth and gradual acceleration will conserve fuel. Quick bursts of speed are addictive in the M8, but they are absolute killers for your fuel bill.

Regularly check tire pressures. Underinflated tires increase rolling resistance, which reduces fuel economy. Consult the sticker on the driver’s side doorjamb for the recommended tire pressures. Maintaining proper inflation also enhances handling and tire wear.

Minimize idling time. If you anticipate sitting for more than a minute, turn off the engine. Modern engines are designed to restart quickly and efficiently, and idling consumes fuel without covering any distance. This applies especially in cities where stop-and-go driving is frequent.

Avoid unnecessary weight. Carrying extra cargo in the trunk or backseat adds weight to the vehicle, which reduces fuel economy. Remove any items you don’t need to carry on a regular basis. This includes golf clubs, extra luggage, or anything else that contributes to added weight.

Plan your routes strategically. Opt for routes that minimize stop-and-go traffic and avoid congested areas whenever possible. Using navigation apps to identify traffic patterns and find the most efficient route can save both time and fuel. Avoid driving during peak traffic hours.