20 MPG combined isn’t going to win any fuel-sipping awards, but for the 2017 Mercedes-Benz S550 4matic, a near-6000-pound, leather-lined, V8-powered fortress of luxury, it’s almost an afterthought. This car isn’t bought by penny-pinchers. It’s for executives, dignitaries, and those who prioritize supreme comfort and effortless performance above all else. They accept the fuel cost as simply the price of doing business, the toll charged for entry into the realm of ultimate automotive indulgence.

City and highway performance

The EPA estimates the S550 4matic at 16 MPG in the city and 25 MPG on the highway. The city figure underscores the inefficiency of stop-and-go driving with a large-displacement, turbocharged engine. The 4.7-liter V8 needs plenty of fuel to overcome its own mass from a standstill, and the turbochargers spooling up only exacerbate the issue. On the open road, however, the S550 becomes far more efficient. The 9-speed automatic transmission allows the engine to cruise at low RPMs, and advanced engine management systems help to conserve fuel when demand is low. The highway number, while not stellar compared to smaller vehicles, is respectable given the S550’s size, all-wheel-drive system, and performance capabilities.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2017 Mercedes-Benz S550 4matic at exactly $2,900. This figure is based on driving 15,000 miles per year, with a certain percentage of those miles driven in the city versus on the highway. The EPA also uses the national average fuel price at the time of calculation. Of course, actual fuel costs will vary considerably depending on individual driving habits and local fuel prices. Drivers who frequently engage in spirited driving or who live in areas with high fuel costs are likely to exceed this estimate.

Real-world expectations

While the EPA estimates provide a baseline, real-world fuel economy for the S550 4matic is highly dependent on the driver. Those with a lead foot will see numbers significantly lower than the EPA’s figures. Conversely, diligent drivers who prioritize smooth acceleration and consistent speeds can often match or even slightly exceed the highway estimate. The S550’s trip computer provides real-time and average fuel consumption data, allowing drivers to monitor their efficiency and adjust their driving habits accordingly. The all-wheel drive system (4matic) adds weight and complexity, contributing to a small but noticeable decrease in fuel economy compared to rear-wheel-drive models.

How it compares

Compared to other flagship luxury sedans of its era, the 2017 S550 4matic lands in the middle of the pack. The BMW 750i xDrive, with its 4.4-liter V8, achieves similar numbers, around 17 MPG city and 25 MPG highway. The Audi A8 L 4.0T quattro comes in slightly better, managing close to 19 MPG city and 29 MPG highway thanks to its slightly smaller engine and more aggressive cylinder deactivation technology. However, the fuel savings are unlikely to sway a potential S550 buyer towards an Audi, as the S-Class offers a distinct experience focused on unparalleled ride quality and a sense of occasion. Potential buyers can always consult S550 MPG across all years for additional research. Those looking to switch brands can also view all Mercedes Benz fuel economy data.

Tips to maximize efficiency

Given its potent powerplant, gentle acceleration is key to maximizing fuel efficiency in the S550 4matic. Avoid abrupt starts and hard braking, as these actions dramatically increase fuel consumption. The engine’s twin turbochargers are responsive, so use them sparingly and allow the transmission to shift smoothly into higher gears to keep the RPMs low.

Proper tire inflation plays a crucial role. Ensure your tires are inflated to the recommended pressure, which can be found on the driver’s side doorjamb or in the owner’s manual. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Regular tire pressure checks are a simple yet effective way to improve MPG.

Using the S550’s “Eco” drive mode can also contribute to lower fuel costs. This mode alters the car’s settings to prioritize efficiency, softening throttle response and optimizing shift points. While it may slightly reduce performance, it can make a noticeable difference in fuel consumption, especially in city driving.

Minimize unnecessary weight in the vehicle always helps. Remove items from the trunk that are not essential, as excess weight adds to the engine’s workload. Even small reductions in weight can have a cumulative effect on fuel economy over time.