20 MPG combined won’t win any awards, but that’s not the main point of the 2020 Porsche 911 Carrera Cabriolet. It’s a high-performance, open-top driving machine, not a Prius. Fuel efficiency is a tertiary consideration, at best, for the buyer who wants the visceral thrill and unmistakable pedigree that comes with owning a 911. They value open-air motoring and the signature wail of a flat-six engine far more than saving on gas.

City and highway performance

The EPA estimates the 2020 Porsche 911 Carrera Cabriolet at 17 MPG in the city and 24 MPG on the highway. These numbers reflect a balance of spirited acceleration and relaxed cruising, but the difference between them suggests the engine’s sensitivity to driving style. The turbocharged 3.0L six-cylinder needs more fuel to deliver its performance when accelerating from a stop or navigating stop-and-go traffic. When driven with more restraint on the open road, the engine uses fuel more conservatively.

Annual fuel cost

The EPA calculates the annual fuel cost for the 2020 Porsche 911 Carrera Cabriolet to be $2,900. This is based on driving 15,000 miles per year and using national average fuel prices. Premium fuel is required, which pushes the real-world cost above this figure. The EPA formula assumes a 55% city and 45% highway driving split. Drivers who spend more time in congested urban areas will likely exceed the $2,900 estimate, while those who primarily take longer highway trips might see a slightly lower annual fuel expense. For more information, we have all Porsche fuel economy data available.

Real-world expectations

The EPA estimates provide a baseline. Your actual MPG will vary based on driving habits, traffic conditions, and even how hard you press the accelerator. Expect to see figures slightly below the official estimates if you frequently use the 911’s performance or if your daily commute involves heavy traffic. However, consistent highway cruising at moderate speeds can yield numbers closer to, or even slightly above, the 24 MPG highway rating.

How it compares

Compared to other performance convertibles, the 2020 911 Carrera Cabriolet’s fuel economy is in the expected range. The BMW Z4 M40i, with its turbocharged inline-six, manages a slightly better 25 MPG combined. The Jaguar F-TYPE Convertible P380, with its supercharged V6, achieves a similar 20 MPG combined. Comparing the Carrera Cabriolet directly to a Z4 or F-TYPE isn’t a perfect comparison. A potential 911 buyer might also consider other 911 variants and might find interest in 911 MPG across all years. Even within the performance car segment, some models prioritize efficiency more than others, potentially affecting a buyer concerned about fuel costs. The 911’s legacy and driving experience often outweighs a slight MPG deficit for its enthusiasts.

Tips to maximize efficiency

While fuel economy isn’t the primary goal, you can improve the 2020 Porsche 911 Carrera Cabriolet’s MPG with some driving techniques. Gentle acceleration will conserve fuel. Avoid aggressive launches and ease into the throttle, letting the engine build power smoothly. This reduces the amount of fuel injected during initial acceleration.

Maintaining a steady speed on the highway will also boost fuel economy. Use cruise control whenever possible to minimize fluctuations in speed and throttle input. Anticipate traffic flow and avoid unnecessary braking and acceleration.

Ensure that your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressures regularly and inflate them to the recommended levels indicated on the tire placard or in the owner’s manual.

Select “Normal” driving mode when performance isn’t a priority. The 911 Carrera Cabriolet offers multiple driving modes, and selecting “Sport” or “Sport+” will alter the engine and transmission settings for optimal performance. Normal mode will deliver the best fuel economy by optimizing engine mapping and shifts.

Reduce unnecessary weight. Remove any extra items from the car. Added weight increases the engine’s workload and decreases fuel efficiency. This can include golf clubs, extra luggage, or anything else that isn’t essential for your drive.