26 MPG combined. This perfectly respectable fuel economy figure manages to hide within the ferocious performance that defines the 2021 BMW M340i. It’s a number that owners will likely acknowledge, perhaps even appreciate on some intellectual level, but certainly not one that dictates the purchase decision for this particular Bavarian bruiser. This is a driver’s car first, a practical sedan second, and a hyper-miler’s dream never.

City and highway performance

The EPA estimates suggest 23 MPG in the city and 32 MPG on the highway for the 2021 BMW M340i. The key here is understanding the engine’s characteristics. The turbocharged 3.0-liter inline-six, lovingly known as the B58, delivers a lot of torque from just off idle. In the city, that urges the driver to exploit the car’s responsiveness, which is not conducive to achieving maximum MPG. However, on the open road, especially with the adaptive cruise control engaged, it can comfortably meet or even exceed the 32 MPG highway rating, thanks to the engine’s inherent efficiency and the eight-speed automatic transmission’s long overdrive ratios. It’s all about managing your right foot, easier said than done when you’re behind the wheel of a car this capable.

Annual fuel cost

According to EPA estimates, the annual fuel cost for the 2021 BMW M340i is approximately $2,250. This figure is based on driving 15,000 miles per year and using national average fuel prices for premium gasoline. Consider that this assumes consistent, fairly average driving habits. If you spend most of your time exploiting the engine’s considerable power, expect that number to climb. Conversely, a predominantly highway commute with a light foot might see it drop, though probably not by a dramatic amount.

Real-world expectations

The official EPA numbers provide a useful benchmark, but in the real world, driver behavior, traffic conditions, and even tire pressures can significantly impact fuel economy. Owners who frequently drive in Sport or Sport+ mode, or who tackle winding backroads, will undoubtedly see lower numbers than advertised. However, even those who prioritize performance can expect to average around 23-27 MPG in mixed driving conditions, which aligns reasonably well with the EPA’s 26 MPG combined rating. The B58 engine delivers both blistering acceleration and relatively thrifty fuel consumption when driven with restraint. Check M340I MPG across all years for a broader picture.

How it compares

Consider the alternatives. The Audi S4, a direct competitor, achieves around 24 MPG combined with its turbocharged V6. The Mercedes-AMG C43, while offering a similar level of performance, also hovers around the 22-24 MPG mark. Even more economical, other variants within the BMW lineup, such as the 330e plug-in hybrid, offer significantly better fuel economy, but at the cost of some performance and a markedly different driving experience. For the M340i buyer, however, a difference of 2-4 MPG is rarely a deal-breaker. They are paying for a specific blend of performance, luxury, and driving engagement, and are prepared to accept the fuel economy as part of the package. This is not, after all, a Prius. It helps to review all Bmw fuel economy data to better understand the range of options available.

Tips to maximize efficiency

Resist the urge to constantly exploit the engine’s considerable power. The B58 is incredibly responsive, and it’s tempting to accelerate hard at every opportunity. However, smooth and progressive throttle inputs will significantly improve fuel economy, particularly in city driving. Anticipate traffic flow and avoid unnecessary braking and acceleration. Coasting to red lights or stop signs, rather than braking hard at the last moment, can save a surprising amount of fuel.

Use the Eco Pro driving mode when appropriate. While it does dull throttle response, it also optimizes various vehicle systems for maximum efficiency, including the transmission and climate control. This mode is particularly effective on the highway, where consistent speeds allow the car to operate at its most efficient.

Ensure that your tires are properly inflated. Underinflated tires increase rolling resistance, which reduces fuel economy. Check your tire pressures regularly and inflate them to the recommended levels, which can be found on the tire placard in the driver’s doorjamb.

Avoid unnecessary weight. Carrying extra cargo in the trunk or on the roof rack increases fuel consumption. Remove any items that are not essential, especially heavy objects. The M340i is a finely optimized machine, and excess weight will impact both performance and efficiency.