German automakers have a long tradition when it comes to deliberately underrating the power of their engines, but we continue to be pleasantly surprised by BMW. The tuners at RaceChip purchased an M3 xDrive a while back and put it on a dyno to find out how much power the S58 engine actually delivers. The official specs sheet may say the inline-six engine is good for 510 horsepower, but this super sedan was making a whopping 553 hp.

As if that wasn’t impressive enough, the dyno test showed the 3.0-liter engine was generating 692 Newton-meters (510 pound-feet) of torque. It represents a healthy advantage of 42 Nm (31 lb-ft) compared to what the manufacturer claims. That’s all in the past now as RaceChip has worked its magic to take twin-turbo mill to a whopping 662 hp and 833 Nm (614 lb-ft).

Peak figures aside, the power curve shows the gains are accessible throughout the entire rpm range, so you basically feel the extra oomph at all times. RaceChip put those numbers to the test by taking their M3 xDrive on an unrestricted section of the Autobahn to perform an acceleration test from 62 to 124 mph (100 to 200 km/h). The high-performance sedan needed as low as 7.04 seconds to get the job done.

Beyond the upgraded engine, the M3 xDrive features a custom body wrap and rides on champagne-colored Edelweiss wheels combined with Eibach springs. The OEM exhaust has been swapped out in favor of a custom Eisenmann setup while keeping the gasoline particulate filter to remain street-legal in Germany and Austria. RaceChip patiently waited about a year to take delivery of the all-paw performance sedan and praises its engine for its strong output in stock form and its tuning potential.

With the S58 already making 553 hp in Competition form, we’d be curious to know how much power it delivers in the M4 CSL and the upcoming 3.0 CSL. The 3.0-liter engine is officially rated at 550 hp in the former while the latter is rumored to pack a mighty 560-hp punch.

Source: RaceChip / YouTube