23 MPG combined isn’t going to win any fuel efficiency awards, but that’s hardly the point of the 2016 BMW 640i xDrive Convertible. This car exists to deliver an open-air grand touring experience, blending potent performance with luxurious features. Its owners prioritize style, comfort, and driving pleasure over squeezing every last mile from a gallon of premium fuel. They accept the reality of single-digit gains relative to a small sedan, in exchange for the visceral thrill of a turbocharged inline-six and the wind in their hair.

City and highway performance

The EPA estimates offer a glimpse into the 640i xDrive Convertible’s fuel consumption across different driving scenarios. City driving, characterized by stop-and-go traffic and lower speeds, yields an estimated 20 MPG. This reflects the engine working harder to accelerate from a standstill and maintain momentum in congested conditions. Out on the open road, where the engine can settle into a more efficient cruising rhythm, the highway MPG figure climbs to 29. Achieving that 29 MPG on the highway demands a gentle right foot and consistent speeds, avoiding sudden bursts of acceleration that will quickly diminish fuel economy. Remember, the xDrive all-wheel-drive system also adds a slight parasitic loss, impacting efficiency compared to a rear-wheel-drive model.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2016 BMW 640i xDrive Convertible is $2,500. This figure is based on driving 15,000 miles per year, using the national average fuel price at the time of calculation. Your actual fuel costs may vary depending on your driving habits, the type of fuel you use (the 640i requires premium gasoline), and local fuel prices. A driver who primarily uses the car for short trips in the city will likely exceed this estimate, while someone who mostly drives long distances on the highway might see lower costs. You can find all Bmw fuel economy data and compare to other manufacturers.

Real-world expectations

While the EPA estimates provide a useful benchmark, real-world fuel economy often deviates. The spirited driving experience the 640i xDrive Convertible encourages can easily lead to lower MPG figures than those advertised. The immediacy of the throttle response and the intoxicating sound of the engine often tempt drivers to accelerate quickly. Conversely, consistent highway driving at reasonable speeds can sometimes yield results that surpass the EPA’s 29 MPG rating. Regular maintenance, including properly inflated tires and timely oil changes, also plays a critical role in maintaining optimal fuel efficiency. Owners should consult resources like the 640I MPG across all years to see trends in owner reported MPG.

How it compares

In the realm of luxury convertibles, fuel economy is rarely a primary concern, but it’s still worth considering how the 640i xDrive Convertible compares against its competitors. The Mercedes-Benz SL450, for example, offers similar performance with an EPA-estimated 20 MPG city and 28 MPG highway. The Audi S5 Cabriolet, with its supercharged V6 and standard all-wheel drive, achieves around 19 MPG city and 28 MPG highway. These small differences often pale in comparison to the overall ownership experience; styling, features, and brand appeal are usually greater concerns.

Buyers in this segment often cross-shop based on individual preferences rather than strictly MPG figures. Some may also consider high-performance two-seaters like the Porsche 911 Carrera Cabriolet (around 18 MPG city/25 MPG highway), appreciating its sharper handling dynamics.

Tips to maximize efficiency

Employ smooth acceleration and avoid hard braking. The 640i xDrive Convertible’s turbocharged engine delivers ample power at low RPM, so there’s rarely a need to bury the accelerator pedal. Gentle inputs will help conserve fuel and reduce wear on the tires and brakes.

Use the car’s driving modes effectively. The “Eco Pro” mode optimizes various vehicle systems to maximize fuel efficiency, sacrificing some performance in the process. Experiment with this mode during highway cruising, where responsiveness is less critical.

Ensure your tires are properly inflated to the recommended pressure. Underinflated tires increase rolling resistance, which negatively impacts fuel economy. Check your tire pressure regularly and adjust as needed.

Minimize unnecessary weight in the vehicle. Excess cargo adds to the overall weight, forcing the engine to work harder and consume more fuel. Remove any items you don’t need, especially heavy objects in the trunk.

Plan your routes to avoid stop-and-go traffic whenever possible. Congested conditions force the engine to operate at its least efficient, burning excessive fuel. Consider using navigation apps to identify alternate routes with smoother traffic flow.