The N55 engine is a legend in the BMW world, known for its potent performance, smooth delivery, and captivating sound. While newer engines have emerged, the N55 continues to hold a special place in the hearts of enthusiasts. This article delves into the specific enhancements BMW made to the N55 for its application in the M2, transforming it into a true performance powerhouse.
BMW engineers essentially rebuilt the N55 from the ground up for the M2, focusing on strengthening and enhancing its capabilities for track use. Key upgrades include a forged crankshaft, forged connecting rods, and updated piston rings. These modifications contribute to a more robust rotating assembly, capable of withstanding higher stresses and sustained high RPM operation. Further enhancements include a redesigned oil pan and a new oil drain pump, promoting optimal oil circulation under extreme driving conditions. To manage increased heat, additional oil coolers were also integrated, ensuring consistent performance even during demanding track sessions. As BMW Product Manager for the M2, Jose Guerrero, explained, maintaining optimal oil and coolant temperatures is crucial for preventing power loss, especially during the high-performance driving the M2 is designed for.
Beyond internal enhancements, the N55 in the M2 received significant upgrades to its cylinder liners. The standard spray-on liners were replaced with more durable cast-iron ones. While sufficient for everyday driving, Guerrero emphasized the necessity of cast-iron liners for the rigors of repeated high-revving track use, preventing potential engine failure under such demanding conditions.
Breathing improvements were also a priority. The M2’s N55 boasts a new exhaust manifold and intake plumbing, optimizing airflow for increased power output. Although BMW hasn’t disclosed the exact boost pressure increase, it’s evident that the M2’s N55 delivers more power than its standard counterpart. This is impressive considering the already substantial tuning potential of the standard N55, capable of reaching nearly 400 hp with software modifications alone.
The modifications to the N55 for the M2 weren’t solely focused on power gains. BMW prioritized durability and stability, ensuring the engine could withstand the demanding driving style expected of M2 owners. This reinforces the N55’s reputation as a reliable and robust engine, capable of handling both daily driving and track abuse.
While the newer B58 engine has taken the reins, the N55’s legacy remains firmly intact, especially in its modified form within the M2. It stands as a testament to BMW’s engineering prowess, delivering a potent and engaging driving experience that continues to thrill enthusiasts. The N55 powered M2 offers a compelling blend of performance, character, and a legendary soundtrack, cementing its status as a modern classic among BMW enthusiasts.
