22 MPG combined won’t win any fuel efficiency contests, but it’s also likely not a major concern for someone considering a 2018 Porsche 911 Carrera 4 GTS Cabriolet. This isn’t just basic transportation, it’s an engaging driving experience delivered with precise German engineering. The kind of person who spends six figures on a topless, all-wheel-drive 911 isn’t also considering a Prius, they’re buying emotion, sound, and the prestige that comes with the Porsche crest. Fuel costs are a rounding error in their overall budget.

City and highway performance

The 3.0L turbocharged flat-six engine, paired with the quick AM-S7 automatic transmission, delivers 20 MPG in the city and 25 MPG on the highway. These figures are EPA estimates, and they represent a balance between the car’s performance potential and theoretical efficiency. The city figure reflects the stop-and-go driving common in urban environments, where the engine works harder to repeatedly accelerate. The highway figure, on the other hand, is achieved at more consistent speeds, allowing the engine to settle into a more efficient cruising range.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Porsche 911 Carrera 4 GTS Cabriolet at $2,650. This calculation is based on driving 15,000 miles per year and using national average fuel prices. It’s a helpful benchmark, but keep in mind that premium fuel is required for optimal performance, and fuel prices fluctuate considerably by region. Someone who drives enthusiastically, or lives in an area with higher fuel prices, can expect to pay significantly more.

Real-world expectations

While the EPA figures provide a baseline, real-world fuel economy depends heavily on driving style. Someone who enjoys the GTS’s strong power and spends a lot of time in Sport or Sport Plus mode will see significantly lower numbers than someone who drives conservatively. Expect to get slightly better than the EPA numbers on long road trips, where you can maintain consistent highway speeds. However, frequent short trips, enthusiastic driving, and city congestion will all negatively impact your MPG. If you’re searching for 911 MPG across all years, remember that newer models often use improved engine technology for better efficiency, but even small gains may not be replicated in real-world scenarios.

How it compares

A comparable BMW M4 Convertible, with its inline-six turbo, achieves a slightly better 25 MPG combined in automatic form. The Mercedes-AMG C63 S Cabriolet, packing a V8, manages only 19 MPG combined, highlighting the efficiency advantage of the Porsche’s flat-six. The Audi R8 Spyder, with its V10, is significantly thirstier at 16 MPG. The Aston Martin Vantage Roadster, another serious contender, gets just 20 MPG combined. These comparisons matter because they contextualize the 911’s fuel consumption within its competitive set. The buyer willing to spend this much on a performance convertible is likely less concerned with outright efficiency, but acknowledging the relative figures demonstrates an understanding of the market.

Tips to maximize efficiency

Use the Normal driving mode when you’re not actively seeking thrills. The Sport and Sport Plus modes alter the car’s throttle response and shift points, which are great for performance but detrimental to fuel economy. The Normal mode provides a more relaxed driving experience and optimizes the engine for efficiency.

Take advantage of the automatic transmission’s coasting function. When you lift off the throttle, the transmission may decouple the engine from the drivetrain, allowing the car to coast freely and save fuel. This is especially effective on downhill stretches.

Maintain proper tire pressure. Underinflated tires increase rolling resistance, which reduces fuel economy. Check your tire pressure regularly and inflate them to the recommended levels listed on the door jamb. This small change can make a noticeable difference over time. Checking all Porsche fuel economy data can also reveal that something like all-wheel drive does not impact efficiency as much as some may believe, as shown by the Carrera 4.

Avoid unnecessary idling. If you’re stopped for more than a minute, turn off the engine. Modern engines are designed to restart quickly and efficiently, and idling consumes fuel without moving the car. This is particularly impactful in city driving.

Plan your routes strategically. Avoid areas with heavy traffic congestion whenever possible. Stop-and-go driving significantly reduces fuel economy. Use navigation apps to find the most efficient routes, even if they’re slightly longer in distance. Minimizing braking and acceleration is key to maximizing fuel efficiency.