20 MPG combined is the stark reality facing anyone who desires the strong power and opulent environment of the 2018 Mercedes-Benz AMG S63 4matic. This isn’t a car bought by people prioritizing fuel efficiency. It’s a four-door missile for those who value handcrafted performance and cutting-edge technology above all else, and who are prepared to pay a premium at the pump for the privilege.

City and highway performance

The official EPA estimates peg the S63 at 17 MPG in the city and 26 MPG on the highway. These numbers reflect the inherent compromise of a twin-turbocharged 4.0L V8 producing a colossal 603 horsepower. Stop-and-go city driving necessitates frequent bursts of power to surge ahead, immediately impacting fuel consumption. Conversely, highway cruising allows the nine-speed automatic transmission to settle into its highest gear, optimizing efficiency, relatively-speaking, of course. Consider these figures as a best-case scenario achievable only with a light foot and disciplined throttle control.

Annual fuel cost

The EPA estimates an annual fuel cost of $2,900 for the 2018 AMG S63. This calculation is based on driving 15,000 miles per year, with a roughly even split between city and highway driving, and using national average fuel prices. Bear in mind that this is simply an estimate. If you primarily drive in the city, or if fuel prices in your area are higher than the national average, you can fully expect to exceed that figure significantly. The S63 also demands premium fuel, adding to the overall expense. For some, it may be worth browsing AMG MPG across all years for a slightly different balance between fun and fuel cost.

Real-world expectations

Forget the EPA numbers in the real world. The S63’s soundtrack of snarling eight-cylinder fury tends to encourage enthusiastic driving, which can easily drag the average fuel economy down into the low teens. A heavy right foot will send the mileage plummeting, while repeated max-power accelerations will make the needle on the fuel gauge move in a way that would make an oil baron blush. Driven sedately, and with liberal use of cruise control on long highway journeys, reaching the EPA numbers is possible, but not likely unless you’re actively trying to conserve fuel. After all, you’ve bought a sledgehammer of performance, so you’re likely planning on using it.

How it compares

Competitors like the BMW M5, also packing a twin-turbo V8 and all-wheel drive, offer a similar blend of performance and luxury. The M5 boasts EPA ratings of 15 MPG city and 21 MPG highway, typically underperforming the S63, but potentially being more efficient in the highway. The Porsche Panamera Turbo, known for its sharper handling, achieves around 19 MPG combined, which is closer to the S63. What separates these vehicles is the character and mission of each car. The Panamera aims for razor-sharp dynamics. The M5 is often marketed towards enthusiasts. The S63 leans towards providing absolute comfort and effortless speed, creating a uniquely luxurious, high-performance experience that might outweigh the fuel economy concerns for its target buyer. You can also explore all Mercedes Benz fuel economy data to compare this S63 to other models within the brand.

Tips to maximize efficiency

Engage the “Comfort” drive mode. While it somewhat dulls the throttle response and loosens the suspension, it will encourage smoother acceleration and earlier upshifts, minimizing fuel consumption. The engine management system will also attempt to run only 4 cylinders when power demands are low.

Anticipate traffic flow and avoid unnecessary braking. Smooth, consistent driving maximizes efficiency. The S63’s brakes use a complex array that can be tough to modulate. Plan ahead to avoid using them. This is more than a fuel-saving tip; it’s a lesson in extracting the most from this unique car.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, negatively impacting fuel economy. The recommended tire pressure can be found on a sticker inside the driver’s side doorjamb. Tire pressure is particularly sensitive in colder weather, so adjust accordingly.

Limit your use of accessories like air conditioning, especially in hot weather. The S63’s climate control system is powerful, but it places a significant load on the engine. Using it judiciously can help preserve fuel.

Lighten the load. Remove any unnecessary items from the trunk and interior. The less weight the engine has to haul, the better the fuel economy will be. This seems minor, but every little bit saves in a car of this weight and complexity.