2013 BMW M5 may have more horsepower than reported
09-07-12, 11:31 AM
#1
2013 BMW M5 may have more horsepower than reported
2013 BMW M5 may have more horsepower than reported
With the 2013 BMW M5 finally going on sale in the U.S., we definitely saw this coming. BimmerPost recently got a hold of engine dyno run for the new M5, and is reporting that the car's twin-turbo V8 is "severely" underrated.
Officially, the M5's 4.4-liter V8 is rated at 560 horsepower and 500 pound-feet of torque, but the dyno graph reveals numbers at the rear wheels to be 527 hp and 476 lb-ft in completely stock form. While the idea of the engine being underrated is just an assumption, the general rule of thumb is a 15-percent drivetrain loss – if accurate, the new M5's losses would be just six percent. Using the 15-percent rule, the 2013 M5 would lay down 476 hp at the wheels.
The idea of BMW underrating its engine outputs is nothing new. Earlier this year, the new 328i show some impressive numbers of its own.
http://www.autoblog.com/2012/09/07/2...than-reported/
09-07-12, 12:58 PM
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Except that the 15% "rule of thumb" is nonsense and always has been. The "drivetrain loss" does not remain at a fixed percentage as you keep going up and up and up in power. The actual "loss" that you'd see on an inertial rolling load dyno like a dynojet for a car at this power level is probably more along the lines of 10% or less, which would put the car within earshot of its actual power ratings. This is just something for fanboys to get excited and chat about. Notice how on all of these super powerful cars that if you apply the 15% rule to all of them, almost all of them are "under-rated" on power? They're not, or at least not by nearly as much as people claim or would like to think. It's because the 15% rule of thumb is BS.
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09-07-12, 08:30 PM
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09-07-12, 10:32 PM
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Except that the 15% "rule of thumb" is nonsense and always has been. The "drivetrain loss" does not remain at a fixed percentage as you keep going up and up and up in power. The actual "loss" that you'd see on an inertial rolling load dyno like a dynojet for a car at this power level is probably more along the lines of 10% or less, which would put the car within earshot of its actual power ratings. This is just something for fanboys to get excited and chat about. Notice how on all of these super powerful cars that if you apply the 15% rule to all of them, almost all of them are "under-rated" on power? They're not, or at least not by nearly as much as people claim or would like to think. It's because the 15% rule of thumb is BS.
09-08-12, 12:17 PM
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Except that the 15% "rule of thumb" is nonsense and always has been. The "drivetrain loss" does not remain at a fixed percentage as you keep going up and up and up in power. The actual "loss" that you'd see on an inertial rolling load dyno like a dynojet for a car at this power level is probably more along the lines of 10% or less, which would put the car within earshot of its actual power ratings. This is just something for fanboys to get excited and chat about. Notice how on all of these super powerful cars that if you apply the 15% rule to all of them, almost all of them are "under-rated" on power? They're not, or at least not by nearly as much as people claim or would like to think. It's because the 15% rule of thumb is BS.
