The 2017 BMW M240i is often celebrated as the sweet spot of the modern enthusiast BMW lineup, and at the heart of this compelling performance coupe lies its meticulously engineered powertrain. While the model name refers to the specific variant within the 2 Series lineup, the engine itself carries its own distinct identity that defines its character and capability. Understanding the nomenclature and technical details of this powerplant is essential for anyone looking to appreciate the precision driving experience BMW engineering offered in that specific year.
Dissecting the Nomenclature: N55 and S55
The primary misconception regarding the 2017 M240i revolves around the engine name. The car is powered by the turbocharged inline-six known internally by BMW as the N55. This specific version of the N55 is tuned for the performance-oriented M Sport models and applications like the M240i. It is crucial to differentiate this from the S55 engine, which is the high-revving, track-focused counterpart found in the F8x M3 and M4. While the S55 is a stroked version of the N55 with individual cylinder shutters, the N55 in the M240i represents the more daily-drive oriented, refined, and efficient implementation of BMW’s twin-scroll turbocharging technology.
Technical Specifications and Output
For the 2017 model year, the N55 engine found in the M240i produced a robust 325 horsepower and 330 lb-ft of torque. This specific output represented a slight increase in power over previous years, thanks to revisions in the intake, exhaust, and engine control unit (ECU) mapping. The power is delivered to the rear wheels via a smooth 6-speed manual transmission or an available 6-speed automatic with paddle shifters, ensuring the driver remains connected to the machine at all times. The efficiency of this power delivery is a testament to BMW’s focus on performance that is not only thrilling but also conscious of fuel economy and emissions.
The Engineering Philosophy Behind the Powerplant
BMW’s design philosophy for the N55 in this era was centered on the concept of "Ultimate Efficiency." This meant extracting significant power from a smaller displacement unit to reduce overall fuel consumption and weight. The use of a single twin-scroll turbocharger eliminates the lag associated with traditional twin-turbo setups, providing immediate power delivery across the rev range. The integration of Valvetronic and Double VANOS technologies allows for precise control of airflow and valve timing, resulting in a linear power curve that is as tractable as it is powerful.
Reliability and Maintenance Considerations
While the N55 engine is a remarkable piece of machinery, potential owners of a 2017 M240i should be aware of specific maintenance considerations common to this generation. The so-called "death wobble," often associated with earlier N54 engines, is less prevalent but periodic inspection of motor mounts and suspension components is recommended. More importantly, the High Pressure Fuel Pump (HPFP) is a known component that, while generally reliable, can be a concern over very high mileage. Staying diligent with service intervals and using high-quality fuel are the best ways to ensure the longevity of this specific powerplant.
Performance Dynamics and Driving Experience
The synergy between the 2017 M240i’s engine and chassis is what truly sets it apart. The low-end torque provided by the turbocharged N55 makes it remarkably agile in urban environments, while the top-end power ensures confident merging onto highways. The transmission calibration prioritizes responsiveness, with quick, sharp shifts that place the driver at the center of the experience. This is not just about raw speed; it’s about the engaging and communicative nature of the machinery, a core tenet of the BMW driving philosophy.
Distinguishing from the M235i and Other Variants
Prior to the M240i designation, the M235i was the top-tier model, powered by the N55 but with a less aggressive tuning and cosmetic package. The introduction of the M240i badge for the 2017 model year clarified the hierarchy, positioning the M240i as the performance leader of the 2 Series range. Essentially, the M240i is the M235i with the full M Sport package, including larger brakes, an M-specific steering wheel, and a more assertive exhaust note, all centered on that same capable N55/S55 family of engines.
Legacy and Conclusion on the 2017 Model
The 2017 BMW M240i stands as a pivotal model in the brand’s history, bridging the gap between affordable sport sedans and genuine driving machines. Its success cemented the inline-six turbo configuration as the standard for enthusiast BMWs for years to come. For the driver, the experience is one of balance—between everyday usability and weekend excitement, between luxury and performance, and between a complex modern engine and its surprisingly manageable maintenance needs.
For the enthusiast considering a used model, understanding that the car is defined by its N55 engine is the first step. It is a unit that offers a genuine connection to the machine, proving that BMW’s commitment to engineering excellence was, and continues to be, very much alive in this specific iteration of the M240i.
