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I need somebody to double check my work I think my math is wrong somewhere

  1. Jan 24, 2009 #1
    I need somebody to double check my work....I think my math is wrong somewhere..

    so I've been working on a spreadsheet to take some data from a vehicle's data port....
    and to transfer it into a Horsepower chart...
    basically making a street Dyno...

    I've gotten everything to work together...including graphing
    but I know that my math has to be wrong somewhere and I need some help to get it right...

    I think I've done all the conversions correctly.....
    I know I've done all the lookup from my data page correctly...

    The Data I used is from a vehcile on the dyno...this vehicle made 447HorsePower and 396 Torque
    but my excel math seems to say it s a lot higher....a lot higher..my end result is 25% or so higher than what it should be...
    I've even added in dyno correction factor that every dynomometer uses to get an SAE corrected value


    My link to my excel spreadsheet...in a zip file...
    too big for me to post it...
    http://www.audiohelix.com/physics/
     
    Last edited: Jan 25, 2009
  2. jcsd
  3. Jan 25, 2009 #2
    Re: I need somebody to double check my work....I think my math is wrong somewhere..

    In a consistent system of units we have:

    Power = Torque * (rotational speed)

    You stated that your are measuring power in units of horsepower (instead of, for example, watts).

    When you say 396 Torque, you are ommiting the units. The most likely possibility in America is foot-lbs, whereas with the metric system torque is measured in newton-meters.

    The metric unit for angular speed is radians per second (not revolutions per second, as engines are often quoted). To convert revolutions per second to radians per second multiply by 2*pi = 6.28.
     
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