BMW says that the current M5 pumps out 600 hp at the crankshaft from its 4.4-liter twin-turbocharged V8 engine while the M5 Competition delivers slightly more at 617 hp.
Both the M5 models currently on sale send their power to the ground through a potent all-wheel drive system and during tests, have been shown to be capable of hitting 60 mph (96 km/h) in under 3 seconds while covering the quarter mile in 11-seconds or less.
Curious as to how a family sedan which weighs over 4200 lbs (1905 kg) can be so fast, Car and Driver decided to hook one up to a dyno to see if BMW has understated power figures for the sedan.
Running in sixth gear to avoid any torque multiplication due to the car’s eight-speed transmission, Car and Driver saw a stock M5 Competition pump out 617 hp and 606 lb-ft (821 Nm) of torque at the wheels. This means the super sedan’s twin-turbo V8 likely pumps out almost 700 hp.
Of course, different dynos can produce different results depending on a range of factors, including weather conditions. However, a result like this is pretty conclusive evidence that BMW is at least somewhat understating power of both the M5 and M5 Competition. This isn’t much of a surprise as many other car manufacturers are known to be very conservative with the power and torque figures they promote, such as McLaren.
The same engine as the M5 and M5 Competition will soon be introduced to the M8 and M8 Competition which according to reports, may benefit from a slightly boost in power. If that’s the case, you can be assured that both will likely have over 700 hp at the engine even if BMW quotes figures below the 650 hp mark.