A lot more clarity is needed on how dyno mode works and how electricity is delivered from the hybrid system.
The aftermarket BMW tuning specialists at IND Distribution have followed up their recent world-first independent dyno measurement of the G87 M2 with the same feat for the all-new G09 BMW XM SUV. For the record, this is neither the range-topping Label Red variant nor the base XM 50e, which is laughably slow compared to the much cheaper X3 M.
No, we're dealing with the XM that was launched first. That means a factory claim of a combined 644 horsepower and 590 lb-ft of torque from the 4.4-liter twin-turbocharged and hybridized V8 powertrain. Can it get close to those figures in real-world independent dyno tests? Let's see.
IND Distribution took the XM to Performance Eurowerks and reports that the XM required additional straps to keep it from coming off the dyno, despite its immense weight (over 6,000 pounds). As with the dyno run of the M2 we referenced above, this XM's engine is not yet broken in fully, so the figures you see here are sure to increase after everything has expanded sufficiently. But where the M2 transmits its fully combustion-powered output to the rear wheels, the AWD XM uses a hybrid system that those operating the dyno do not yet fully understand.
We'll get to that shortly, but the headline figures recorded at the wheels are 614.84 hp and 569.14 lb-ft of torque. BMW has a habit of underquoting its power figures, and it appears that this car is no different. Assuming an approximate drivetrain loss of 20%, this hulking behemoth theoretically produces around 768 hp and 712 lb-ft at the crank.
However, there is a caveat to those figures. The dyno and the XM's in-vehicle gauges indicated that the hybrid system was active, but it spiked at 6,500 rpm, which you can see on the above graph. Why did it do this? Would more break-in miles fix the issue? Should the battery have been fully charged? Is the XM's hybrid system confused by dyno mode?
These questions remain unanswered, but to give us a clearer idea of what the power figures may be like without an anomaly, IND removed the spike from the equation and arrived at figures of 573.49 hp and 516.42 lb-ft of torque at the wheels. Assuming the same approximate 20% drivetrain loss, the XM's crank figure would be 715 hp and 645 lb-ft. Either way, the XM continues BMW M's tradition of overdelivering on power, even if the hybrid system is finicky.
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