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The all-new F97 X3M is the welcomed newcomer amongst BMW's M garage, not only as the upper crust of the X3 lineup, but certainly because of what's under the hood—the S58 engine. Rated at 473 horsepower and 442 pound-feet of torque in the new X3 M and X4 M, and at 503 horses in the Competition versions, it's the most powerful six-cylinder gasoline engine BMW has built to date.
A double treat, then, to be able to see what the X3M can do despite BMW's traditionally modest claims, but also, for all intents and purposes, a sneak preview for the upcoming M3 and M4's potential.
We arrived at AMS Performance on a hot and humid day, the 89 Octane delivery fuel still sloshing around in the tank and a mere 114 miles on the odometer. It would seem, then, that the odds were stacked against us to make any sort of newsworthy claims. Nevertheless, anticipation was high—the AMS crew brought the S58 to life, crept our X3M onto the rollers, and safely strapped it down. It sat there poised and eager to perform as we gave its athletic proportions one last approving nod.
The fans switched on as the wheels began to spin on the rollers. Gear shifts through first, second, and third came and went without any theater. But when fourth arrived, the revs climbed with urgency to redline, the rollers screamed to keep up with the X3M's torque demands. Sport Plus gave us an aural treat when the X3M came off throttle, a slew of satisfying burbles filled the air as the X3M settled back down to rest.
And then we saw it: 491 horses and 446 pound-feet of torque at the wheels on measly 89 Octane. At roughly ten percent drivetrain loss, you can do the math (and in case you can't, we've broken it down below).
We decided it'd be an opportune time to also verify BMW's curb weight claims before making our way back to IND, so onto a set of scales it went. 4510 lbs was the net result with just under half a tank and the Competition's 21" wheel / tire combo. Weight distribution was pure BMW at nearly 50/50.
Despite the conditions, we were absolutely thrilled by the baseline results and are eagerly looking forward to developing our new X3M project over the upcoming months. Stay tuned for more!
BMW X3MC (10% Drivetrain Loss): 452.7 hp, 397.8 tq
IND X3MC (10% Drivetrain Loss): 491.7 hp, 446.1 tq
BMW X3MC (Crank): 503hp, 442 tq
IND X3MC (Crank): 542hp, 490.3 tq
BMW X3M40i Curb Weight: 4,317 lbs
BMW X3MC Curb Weight: 4,620 lbs
IND X3MC Curb Weight: 4,510 lbs (half tank)