Thread: First Time On the Dyno

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  1. #1 Re: First Time On the Dyno 
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    No, Horsepower is not being measured by the dyno. It is being calculated by torque and RPM pure and simple. If the dyno only displays horsepower and not torque then it's because the operator didn't select it to graph. Look up horsepower, and it's defination. Horsepower is work done over time. It is calculated either using eddy currents and converted from electrical HP or its calculated on the time it takes to spin a large drum, but the calculation is always the same 5252 is the standard established based on something like 33000 foot lbs per minute. If the dyno lines do not cross at 5252 something went wrong and it is an invalid pull. When I dynoed my Tbird and Diablo back in the day if the dyno didn't cross at 5252 then we redid the pull. I was always told "mmm, something didn't go right." And the setup would be checked again and usually they would snug down the straps. When I was in school and studied power we went over and over this. We had to be able to convert all kinds of power numbers, Dynes,Watts, HP, Torque/Time/ BTU's all that junk, and the one thing I always asked is how do you measure HP, my professors always said "HP isn't measured, it's calculated."

    Jeff

    not to take away from the OP, accomplishments, but something wasn't t correct on the first pull. It's not possible to have torque and HP not cross at 5252 rpm.


    Math does not lie
    An engine is an engine no matter the size.... I think Dr. Seuss said that... or maybe it was Big Weld....
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  2. #2 Re: First Time On the Dyno 
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    Quote Originally Posted by J57ltr View Post
    No, Horsepower is not being measured by the dyno. It is being calculated by torque and RPM pure and simple. If the dyno only displays horsepower and not torque then it's because the operator didn't select it to graph. Look up horsepower, and it's defination. Horsepower is work done over time. It is calculated either using eddy currents and converted from electrical HP or its calculated on the time it takes to spin a large drum, but the calculation is always the same 5252 is the standard established based on something like 33000 foot lbs per minute. If the dyno lines do not cross at 5252 something went wrong and it is an invalid pull. When I dynoed my Tbird and Diablo back in the day if the dyno didn't cross at 5252 then we redid the pull. I was always told "mmm, something didn't go right." And the setup would be checked again and usually they would snug down the straps. When I was in school and studied power we went over and over this. We had to be able to convert all kinds of power numbers, Dynes,Watts, HP, Torque/Time/ BTU's all that junk, and the one thing I always asked is how do you measure HP, my professors always said "HP isn't measured, it's calculated."

    Jeff

    not to take away from the OP, accomplishments, but something wasn't t correct on the first pull. It's not possible to have torque and HP not cross at 5252 rpm.


    Math does not lie
    On an inertia dyno, horsepower is measured, and torque is calculated via spark signal. If you are not able to pick up spark, you will not get a torque curve.


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