A 3.0-liter twin-turbo inline-six in a BMW M4 Coupe produces 431 horsepower, as it should in a proper M car. Since the new X4 M40i isn’t actually a proper M car, you only get 355 horses from its 3-liter twin-turbo inline-six. Will that do?
Not that it isn’t a clever engine. BMW says that compared to the one you find in the former performance champ X4 xDrive35i, the M40i’s unit was constructed with a closed-deck design, meaning that the water jacket surrounding the cylinders is sealed at the top, endowing the crankcase with an exceptionally high degree of stiffness.
BMW also gave it a new oil cooler, high pressure injectors, turbos integrated into the exhaust manifold operating at a higher boost, an optimized air intake manifold, a forged crankshaft, pistons with a modified top ring and high-performance spark plugs.
Wait a second. Hang on! Isn’t this the BMW M2’s engine, detuned by just ten horses?
Sure sounds like it, but either way, choosing the most powerful X4 yet will provide you with 355 hp at between 5,800 and 6,000 rpm and a maximum torque of 343 lb-ft. That good enough for a run to sixty mph in just 4.7 seconds.
The xDrive system was recalibrated to send more power to the rear wheels, while the list of chassis upgrades includes beefier springs and stabilizer bars, an increased camber on the front axle and the dampers tuned to M spec as well.
The wheels are 20-inch alloys wrapped in Michelin’s Pilot Super Sport rubber, while the rest of the exterior is dominated by “Ferric Gray” metallic accents and “Black Chrome” tailpipes. BMW uses valves and different resonator tuning for the M40 double-flow exhaust to have a reassuring grunt.
Of course your neighbor’s X6 M will still smoke it.