The X3 is BMW’s compact crossover SUV, and the X4 is the lower-roofline, sportier-silhouette hatchback version of the same vehicle meant to appeal to younger buyers. The “Competition” designation denotes the still-higher-performance and still-more-expensive versions of both vehicles, and it is Competition versions journalists are testing at and around New York’s Monticello Motor Club country club racetrack. The X3 M and X4 M are indistinguishable from behind the wheel and on their spec sheets, so the only difference is which you prefer. That, and the unfortunate absence of overhead grab handles for passengers in the X4 M.
Tall and taut
Driving on the rolling rural byways of New York and northern New Jersey in the vicinity of the Monticello race circuit, the X3 M and X4 M feel, well, exactly like BMWs. That means the thick-rimmed, leather-wrapped steering wheel provides direct feedback and immediate response to steering inputs.
Especially impressive is the vehicle’s ability to change direction through switchbacks, as the active dampers help the BMW hide its bulk. The active all-wheel drive similarly helps minimize understeer in the slow corners, where a heavy machine with power passing through the front tires would normally frustratingly succumb to sliding its front end.
One contributor to this Toronto Red X4 M Competition’s handling prowess is the addition of chassis braces that reinforce the regular platform to prevent it from twisting under the incredible loads generated by the M upgrades. There are five additional or beefier braces at the front of the chassis and three more or enlarged ones at the rear. Models with a sunroof get another A-frame brace under the bottom of the vehicle at the rear to further resist twisting forces.
This is critical because “the chassis is the biggest suspension component,” Barbisch noted. The aim is to take it out of the equation as much as is possible by making it as stiff as is practical. The result is a pair of crossovers that drive much like their M3 and M4 cousins, just higher.
Regular X3 M/X4 Ms roll on dubs, but the Competition models I tested mount their huge Michelin Pilot Sport 4S rubber to 21-inch wheels.
Pinnacle of inline-6 power
BMW’s most-powerful straight-6 ever, a twin-turbocharged 3.0-liter unit, lives under the hood of both vehicles. In regular X3 M/X4 M trim, it produces 473 horsepower and 442-pound-feet of torque. In Competition spec, horsepower rises to 503, but torque is unchanged. It powers all four wheels through an 8-speed automatic transmission.
Fully 90 percent of this engines are different from previous BMW 3.0-liter straight-6s. This engine has a larger bore and a shorter stoke, as well as a forged crankshaft and forged pistons, to push the rev limit to 7,700 rpm. In the Competition version, the air intake and exhaust systems are enlarged for better flow at maximum revs.
The engine engineers seem most proud of how quickly the straight-6 revs. In fact, I found it revs so fast that, with the transmission in manual mode, it can be easy to hit the rev limiter when coming out of slow, second-gear corners on the track. It’s probably better to leave it in automatic mode than to play Formula One driver by squeezing the paddles.