While 26 MPG combined won’t top any fuel efficiency charts, the 2023 BMW Z4 M40i 3.0L 6-cyl isn’t designed to. It’s a roadster built for fun driving and top-down enjoyment. Its buyers value performance and the feeling of driving over saving gas, but knowing its consumption is still part of ownership.

City and highway performance

The EPA estimates the Z4 M40i will get 23 MPG in the city and 31 MPG on the highway. The 23 MPG city number reflects the engine’s power, which encourages quick acceleration, hard to resist in stop-and-go traffic. The 31 MPG highway rating shows relaxed cruising, where the eight-speed automatic transmission settles into higher gears, saving fuel. These ratings are possible, but only with a light foot; fast acceleration will drop them significantly.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2023 BMW Z4 M40i at $2,250. This is based on driving 15,000 miles per year, using the national average fuel price for premium gasoline when they calculated this. The Z4 M40i needs premium fuel for best performance and engine protection, so this number is a good budgeting guide. Your actual fuel costs will vary based on your driving, local fuel prices, and how many miles you drive each year.

Real-world expectations

The EPA estimates are a standard comparison, but real-world fuel economy for the Z4 M40i depends a lot on how you drive. If you often use the engine’s 382 horsepower, expect numbers below the combined 26 MPG. However, drivers who accelerate smoothly and maintain consistent highway speeds might get close to, or even slightly beat, the EPA’s estimates. Hilly roads, heavy traffic, and weather can also change fuel consumption.

How it compares

The Z4 M40i’s fuel economy puts it in a performance roadster group. A Porsche 718 Boxster S, with its 2.5L turbocharged engine, gets a similar 22/29/25 MPG (City/Highway/Combined). The Mercedes-Benz SLK 350, no longer made, had similar performance and fuel economy when it was new. A sports car like a Mazda MX-5 Miata gets much better fuel economy (26/34/29 MPG), but offers a very different driving experience focused on lightweight agility instead of the Z4 M40i’s blend of luxury and power. For those interested in seeing all Bmw fuel economy data, you can explore their other offerings. Also, take a look at the Z4 MPG across all years and engine options.

Tips to maximize efficiency

Because the Z4 M40i is performance-focused, hypermiling might seem strange, but you can still improve fuel economy without losing all the fun. Watch traffic flow and avoid fast acceleration and hard braking, which waste fuel. Smooth acceleration will make a difference.

Make sure your tires are inflated to the recommended pressure, on the driver’s side doorjamb. Underinflated tires increase rolling resistance, making the engine work harder and use more fuel. Check tire pressure regularly, especially when temperatures change.

Avoid unnecessary idling. If you’re stopped for more than a minute, turn off the engine. Modern engines restart quickly and efficiently, so restarting uses less fuel than idling. This is important in cities where idling is common.

Use cruise control on the highway when possible to keep a consistent speed and reduce unnecessary acceleration and deceleration. This works best on long, flat roads, where cruise control can help save fuel. Disengage cruise control in variable traffic or difficult road conditions.