20 MPG combined won’t win any fuel economy awards, but for the 2017 Mercedes-Benz S550 Convertible, it’s almost beside the point. This car isn’t about practicality or frugality; it’s about experiencing open-air luxury with a potent V8 engine. The S550 Convertible is for a buyer who values performance and prestige above all else, and who likely has other, more economical vehicles in their garage.

City and highway performance

The EPA estimates the S550 Convertible achieves 17 MPG in the city and 25 MPG on the highway. The city figure reflects the demands placed on the 4.7L V8 engine in stop-and-go traffic. That engine, tuned for effortless power delivery, prioritizes responsiveness over absolute efficiency. The highway number, while better, still isn’t exceptional, owing to the car’s size, weight, and the V8’s inherent thirst, even working with the 9-speed automatic transmission to optimize fuel usage at cruising speeds. This blend of city and highway figures emphasizes that the S550 Convertible is most rewarding on longer drives, where its powerful engine and luxurious appointments can truly shine.

Annual fuel cost

According to the EPA, the annual fuel cost for the 2017 Mercedes-Benz S550 Convertible is estimated to be $2,900. This figure is based on driving 15,000 miles per year and using national average fuel prices. Keep in mind that this is only an estimate, and your actual fuel costs may vary depending on your driving habits, the type of fuel you use, and local gas prices. This sum highlights the financial commitment required to enjoy the S550 Convertible’s performance and luxury, but it’s a cost most buyers in this segment are willing to bear.

Real-world expectations

While the EPA provides a baseline, real-world MPG for the S550 Convertible can vary significantly based on driving style. Expect to see numbers closer to the EPA estimates with gentle acceleration and consistent highway speeds. However, if you frequently indulge in the V8’s ample power or spend a significant amount of time in heavy traffic, you’ll likely see fuel economy dip below the official figures. Owners focused on maximizing efficiency may achieve slightly better results through careful driving habits, but fuel economy isn’t the primary focus for most S550 Convertible drivers.

How it compares

The BMW 650i Convertible, a direct competitor, offers similar performance and luxury. It achieves an EPA-estimated 17 MPG city and 25 MPG highway, mirroring the S550. The Audi S5 Cabriolet, though smaller and with a supercharged V6, manages a slightly better 21 MPG combined. However, that car prioritizes agility over the pure grand-touring experience of the S550. The Porsche 911 Carrera Cabriolet, another option, comes in around 20 MPG combined as well, but it is more of a sports car than the ultra-luxury S550. Those considering all Mercedes Benz fuel economy data should also compare other models. Understanding the S550 MPG across all years provides additional context for its fuel efficiency.

Tips to maximize efficiency

Take advantage of the S550’s ECO drive mode. This setting adjusts the engine and transmission mapping to prioritize fuel efficiency, resulting in smoother acceleration and earlier upshifts. While it won’t transform the S550 into a fuel sipper, it can contribute to a small improvement in MPG, especially during daily commutes.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and reducing fuel economy. Regularly check your tire pressure and inflate them to the recommended levels, which can be found on the driver’s side doorjamb or in the owner’s manual.

Minimize idling time. Letting the engine idle for extended periods wastes fuel. If you’re stopped for more than a minute, consider turning off the engine. The S550’s engine management system allows for quick and reliable restarts.

Drive smoothly and avoid aggressive acceleration. The S550’s powerful engine is responsive, but heavy acceleration burns fuel. Try to anticipate traffic flow and maintain a steady speed to optimize fuel economy.