Well, the end result is 527 rear wheel horsepower completely stock on pump gas. This dyno comes to us courtesy of our Premier Vendor IND-Distribution whom we thank for sharing it with us.
To put this power in perspective, the X5M and X6M put down 456 all wheel horsepower stock on 93 octane in SAE on a dynojet. So the M5 is much, much stronger partially due to routing the power to the rear wheels with a dual clutch transmission versus all four with an automatic and also due to more boost with higher compression.
For those who like to calculate drivetrain losses, the M5 is rated at 560 horsepower stock. That would put the drivetrain losses at 6%. Using the traditional dynojet standard of 15% the rear wheel horsepower should be at 476. BMW is underrating the new turbo motors and especially the M motors considerably. We are definitely glad they are over-delivering.