20 MPG combined won’t win any fuel economy awards, but it’s what you can expect with the 2018 BMW 650i Convertible. This isn’t a vehicle for those obsessed with fuel efficiency. It’s for someone who prioritizes fresh air, strong power, and the BMW convertible brand, accepting the fuel consumption as a part of owning it.

City and highway performance

The EPA estimates the 650i Convertible gets 17 MPG in the city and 25 MPG on the highway. This difference is due to the engine: a turbocharged 4.4L V8 that needs more fuel when accelerating or in stop-and-go traffic. Once at speed on the highway, the engine becomes more efficient, helped by the smooth-shifting 8-speed automatic transmission (S8). Highway driving, with the top down, is where this car is best. It provides a great driving experience and reasonable fuel economy. See 650I MPG across all years.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 BMW 650i Convertible is $2,900. This is based on driving 15,000 miles per year, with a percentage for city versus highway driving, and the national average fuel price. Your actual fuel costs will change based on how much you drive and where you live, since fuel prices differ across the country. This $2,900 gives potential owners an idea of the cost of fueling this convertible.

Real-world expectations

EPA figures offer a comparison, but real-world fuel economy will differ depending on driving style, traffic, and weather. Hard acceleration, braking, and idling will hurt fuel consumption. Many 650i owners who often use the engine’s power likely see MPG lower than the EPA estimates. However, drivers who accelerate smoothly and avoid idling may get closer to, or even better than, the stated figures.

How it compares

The 650i’s fuel economy is normal compared to other luxury performance convertibles. The Audi S5 Cabriolet, with its supercharged V6, gets around 21 MPG combined. The Mercedes-Benz C43 AMG Cabriolet, with a turbocharged V6, gets similar numbers. A V8, like the one in the Mercedes-Benz SL550, means accepting about 19 MPG combined. The Porsche 911 Carrera Cabriolet might be slightly more efficient at around 22 MPG combined, but costs more. These comparisons are important. Buyers know high performance comes with a fuel cost, but they want information compared to similar cars. Be sure to check all Bmw fuel economy data before making a purchase decision.

Tips to maximize efficiency

Use the driving mode selector. The 650i offers driving modes, including “Eco Pro,” which changes vehicle systems to prioritize fuel efficiency. While it won’t turn the V8 into a Prius, it can help you save gas in everyday driving.

Keep tires properly inflated. Under-inflated tires increase rolling resistance, making the engine work harder and use more fuel. Check your tire pressures often and inflate them to the recommended levels, found on a sticker inside the driver’s side doorjamb.

Avoid idling. Idling uses fuel without going anywhere. If you’ll be stopped for more than a minute, turn off the engine and restart it when ready. This is efficient with modern engines that restart fast.

Watch traffic. By watching the road and anticipating traffic changes, you can avoid unnecessary acceleration and braking. Maintaining a speed is more fuel-efficient than speeding up and slowing down.