16 MPG combined is not a number anyone shopping for a 2017 Mercedes-Benz S65 AMG Convertible will dwell on for long. This isn’t a car bought for its thrifty nature; it’s purchased for the sheer, unadulterated thrill of a hand-built 6.0L V12 engine producing 621 horsepower, combined with the sensory experience of open-air motoring. Fuel efficiency is a distant afterthought for the privileged few who sign on the dotted line for this automotive indulgence.

City and highway performance

The EPA estimates for the S65 AMG Convertible break down to 14 MPG in the city and 21 MPG on the highway. The city figure reflects the stop-and-go nature of urban driving, where the massive engine constantly works to overcome the car’s substantial weight. The highway number, while better, still showcases the fuel demands of a large-displacement engine, even when cruising. The 7-speed automatic transmission is a contributing factor here; while generally smooth and responsive, it’s tuned for performance rather than ultimate efficiency. Modern 8, 9, or even 10-speed transmissions, common in more fuel-conscious vehicles, allow engines to spend more time in their most efficient operating range.

Annual fuel cost

Ownership of an S65 AMG Convertible comes with financial considerations beyond the hefty purchase price. The EPA estimates an annual fuel cost of $3,600. This figure is based on driving 15,000 miles per year, with approximately 55% of those miles driven in the city and 45% on the highway, using the national average fuel price for premium gasoline. Of course, actual fuel costs can vary significantly depending on individual driving habits, local fuel prices, and the amount of time spent exploiting the engine’s prodigious power.

Real-world expectations

While the EPA provides a standardized estimate, real-world fuel economy for the S65 AMG Convertible is likely to be lower, especially for drivers who frequently indulge in spirited driving. The V12 engine is remarkably responsive, and the temptation to unleash its full potential is ever-present. This often translates to more time spent in lower gears, at higher engine speeds, consuming fuel at a significantly faster rate. Owners who prioritize fuel conservation and adopt a gentle driving style may be able to approach the EPA estimates, but that’s not the primary objective for most S65 AMG Convertible buyers.

How it compares

Compared to other high-performance luxury convertibles, the S65 AMG’s fuel economy is predictably low. For example, the V8-powered BMW M850i Convertible manages around 20 MPG combined, a notable improvement, though it lacks the V12’s unique character. The Porsche 911 Turbo S Cabriolet, with its turbocharged flat-six engine, achieves around 18 MPG combined, delivering similar performance with slightly better fuel efficiency. Ultimately, shoppers deciding between these vehicles aren’t making economy their top priority. They are focused on factors like brand cachet, exclusivity, and the visceral driving experience, making compromises on fuel consumption acceptable.

For those who love this brand and want to compare all Mercedes Benz fuel economy data, or just want to examine S65 MPG across all years, there are plenty of resources available.

Tips to maximize efficiency

While squeezing every last mile out of each gallon might not be the primary concern for S65 AMG Convertible owners, there are still a few strategies to consider. Avoid aggressive acceleration and braking. The V12 engine delivers ample power even at low RPMs, so there’s rarely a need to push it hard during everyday driving.

Regular maintenance, including timely oil changes and proper tire inflation, can also contribute to improved fuel efficiency. A well-maintained engine operates more efficiently, and properly inflated tires reduce rolling resistance, both leading to marginal gains in MPG.

Use the car’s driving modes. The S65 AMG Convertible typically offers a “Comfort” or “Eco” mode that adjusts the engine and transmission settings for smoother, more fuel-efficient operation. While it might slightly dampen the car’s performance, it can make a difference during long highway cruises.

Consider the route. Avoiding stop-and-go traffic when possible can significantly impact fuel consumption. Planning routes that prioritize smooth, consistent speeds can help you stay closer to the EPA’s highway MPG estimate.