2013 BMW M5 packs more horsepower than advertised
The 2013 BMW M5 is powered by a twin turbocharged 4.4L V8; an engine that is supposed to offer 560 horsepower and 500lb-ft of torque. This output makes the new M5 one of the most powerful sport sedans in the world but according to the folks at the BMW enthusiast community BimmerBoost, the M5 is more powerful than advertised – a whole lot more powerful.
A dyno sheet posted with the test results of a factory stock US-specification 2013 BMW M5 shows that the high performance sedan puts 527.18 horsepower to the ground around 6,600rpm with the peak torque measuring 476lb-ft right around 3,200rpm. Mind you, that is power at the wheels whereas stated horsepower is at the crankshaft but compared to the stated figures of 560hp and 500lb-ft of torque – the actual power at the wheels seems to be a bit higher than they should be. The difference between the stated horsepower figure of 560 and the power at the wheels of 527 means accounts for only a 6.3% drivetrain loss while the torque lost is only around 5%. The industry standard that is typically used for a rear wheel drive car in terms of expected “loss” between the engine and the wheels is 15%, which would suggest that the M5 should put around 476 horsepower and 425lb-ft of torque to the rear wheels. This means that the 2013 M5 is either the most efficient vehicle ever in terms of drivetrain losses – or the German automaker underrated the power output of their super sedan.
If we apply the 15% rule to the actual rear wheel output of the 2013 BMW M5, it indicates that the twin turbo V8 is making somewhere in the area of 620 horsepower…a whopping 60 more than advertised. Keep in mind, this 15% rule is far from perfect but even if we assume that the 2013 M5 offers an incredible 10% drivetrain loss, 527 rear wheel horsepower still equates to 586 horsepower at the crankshaft. There is a chance that the dual clutch gearbox at work in the M5 is incredibly efficient so the new high performance sedan could prove to have legendarily low drivetrain losses but even with 10%, we can see that the twin turbo V8 is underrated.