20 MPG combined isn’t going to win any awards, but for the 2015 Mercedes-Benz E550 Convertible, it’s a figure largely irrelevant to its target demographic. This is a car purchased for the experience: the wind in your hair, the burble of a twin-turbo V8, and the overall feeling of effortless luxury. Fuel economy is a tertiary concern, at best, for the buyer who prioritizes open-air motoring and potent performance.

City and highway performance

The EPA estimates the E550 Convertible achieves 17 MPG in the city and 25 MPG on the highway. The spread reflects the engine’s nature. Around town, the V8’s considerable weight and eagerness to accelerate affect efficiency. The stop-and-go grind reduces efficiency. Out on the open road, however, the engine’s ample torque allows it to cruise easily. The seven-speed automatic transmission finds the optimal gear, and the aerodynamic profile helps minimize drag, resulting in a noticeably better highway figure. You’ll see closer to that 25 MPG number on long road trips where you’re not constantly dipping into the throttle.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2015 Mercedes-Benz E550 Convertible is $2,900. This figure is based on driving 15,000 miles per year and using the EPA’s fuel consumption estimates with a national average fuel price. Keep in mind, this is just an estimate. Your actual fuel costs will vary depending on your driving habits, the type of driving you do, and local fuel prices. For example, aggressive driving or frequent short trips (where the engine doesn’t reach optimal operating temperature) will significantly increase your fuel consumption and, consequently, your annual fuel costs.

Real-world expectations

Expect to see figures slightly below the EPA estimates in real-world driving conditions. The temptation of the V8’s power is hard to resist, and frequent bursts of acceleration will quickly drop your average MPG. City driving, with its traffic jams, stoplights, and general inefficiency, will especially drag down your numbers. Owners reporting fuel economy on sites like Fuelly.com tend to average close to the EPA rating, but the range of observed values is broad. Those who prioritize efficiency and resist the urge to plant their foot will likely do better, while drivers who use the engine’s available power more frequently will see lower numbers. It’s all a balance, and one that requires conscious acknowledgment of your priorities behind the wheel.

How it compares

The 2015 E550 Convertible competes against other high-performance luxury convertibles. The BMW 650i Convertible, with its similarly powerful V8, delivers comparable fuel economy, hovering around 17 MPG city and 25 MPG highway. The Audi S5 Cabriolet, with its supercharged V6, offers slightly better fuel economy, registering around 18 MPG city and 28 MPG highway. The key difference is that the S5 sacrifices some of the E550’s raw power to achieve those numbers. Buyers considering the E550 aren’t primarily focused on efficiency; they’re looking for a blend of performance, luxury, and open-air enjoyment. If maximum fuel economy is the goal, there are countless better options. But if a potent V8 is a non-negotiable requirement for your convertible, then the E550’s fuel consumption is simply part of the price of admission. Those looking for alternative Mercedes Benz models can find all Mercedes Benz fuel economy data on our website.

Tips to maximize efficiency

Take advantage of the E550’s “Eco” driving mode. This setting optimizes the engine and transmission for efficiency, resulting in smoother acceleration and earlier upshifts. It won’t transform the car into a hybrid, but it can make a noticeable difference in fuel consumption, especially in city driving. Instead, use cruise control whenever possible on the highway. Maintaining a consistent speed minimizes unnecessary acceleration and deceleration, which translates to better fuel economy.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which forces the engine to work harder, decreasing fuel efficiency. Check your tire pressure regularly and inflate them to the recommended level, which can be found on a sticker inside the driver’s side doorjamb. Consider that the added weight of the convertible mechanism does affect fuel economy. Removing any unnecessary weight from the car can also help to slightly improve fuel economy.

Avoid aggressive driving habits such as hard acceleration and braking. These habits consume a significant amount of fuel. Instead, accelerate smoothly and brake gently. Anticipate traffic flow and maintain a safe following distance to minimize the need for sudden stops. Remember that the 4.7L V8 benefits from premium fuel. Always use the manufacturer-recommended octane rating to prevent engine knocking and ensure optimal fuel efficiency and performance. Information on E550 MPG across all years can be found here.