The 2021 Porsche 911 Turbo S Cabriolet achieves 17 MPG combined. Buyers of this open-top, all-wheel-drive car likely aren’t prioritizing trips to the gas station. They’re buying a visceral driving experience, blistering acceleration, and topless thrills. Fuel efficiency is a lesser consideration, overshadowed by the joy of 640 horsepower.

City and highway performance

The EPA estimates 15 MPG in the city and 20 MPG on the highway for the 911 Turbo S Cabriolet. These numbers reflect its performance-oriented design. The city figure is low due to urban driving’s stop-and-go nature, where the powerful engine constantly accelerates from a standstill. The highway figure improves, but even cruising at legal speeds doesn’t allow for optimal fuel conservation in a car designed for triple-digit speeds on the Autobahn. The twin-turbocharged 3.7-liter flat-six engine, coupled with the quick-shifting eight-speed PDK transmission, prioritizes power over efficiency. This focus delivers unparalleled acceleration but affects fuel consumption.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2021 Porsche 911 Turbo S Cabriolet at $3,400. This figure is based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway, using national average fuel prices for premium gasoline. Your individual fuel costs may vary depending on your driving habits and local fuel prices. Aggressive driving or extended idling in traffic will increase your fuel consumption and push that annual cost higher than the EPA estimates. Gentler acceleration and more highway driving can potentially lower it. However, restraint isn’t usually the owner’s first thought.

Real-world expectations

While the EPA provides a standardized measure, real-world fuel economy for the 911 Turbo S Cabriolet will likely vary. Drivers who frequently exploit the car’s performance capabilities will likely see figures below the EPA estimates. A heavy foot on the accelerator transforms those turbos into a fuel-consuming experience. Owners who primarily use the car for leisurely weekend drives and resist the temptation to constantly unleash its power might achieve numbers closer to, or even slightly above, the EPA estimates. Buying a Turbo S and trying to hypermile is like buying a racehorse and making it pull a plow. It defeats the purpose.

How it compares

Compared to other high-performance convertibles, the 911 Turbo S Cabriolet’s fuel economy is predictably low. The Mercedes-AMG SL 63, with its 4.0-liter V8, achieves a combined EPA rating of 16 MPG, making it nearly identical in fuel consumption. The Audi R8 Spyder V10 performance, another all-wheel-drive convertible, manages a slightly better 18 MPG combined, thanks to its naturally aspirated engine, but it still trails more mainstream luxury convertibles significantly. A BMW M8 Competition Convertible only attains 17 MPG combined as well. 17 MPG is the going rate for breathtaking performance; these numbers highlight the trade-off enthusiasts make for the thrill of these powerful cars. You can explore all Porsche fuel economy data to see how other models compare, and 911 MPG across all years.

Tips to maximize efficiency

Despite its performance-oriented nature, some driving habits can marginally improve the 911 Turbo S Cabriolet’s fuel economy. Smooth acceleration and avoiding sudden braking can reduce fuel consumption, especially in city driving. Anticipate traffic flow and maintain a steady pace to minimize the need for hard acceleration.

Ensure your tires are properly inflated. Low tire pressure increases rolling resistance, forcing the engine to work harder and consume more fuel. Regularly check your tire pressure and inflate them to the recommended levels.

Minimize idling. Modern engines consume fuel even when stationary. If you’re stopped for more than a minute, consider turning off the engine, particularly in city traffic, where prolonged idling can significantly impact fuel economy.

Use the Porsche’s driving modes carefully. While “Sport” and “Sport Plus” modes enhance performance, they also increase fuel consumption. Choose “Normal” mode when cruising or driving in less demanding conditions to optimize fuel efficiency.