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Old 05-17-2016, 11:37 AM   #108
brandonblt2
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Quote:
Originally Posted by mdm View Post
This is actualy completely wrong. There is nothing special about the 5,252 number, nothing changes qualitatively about the engine operation at that RPM.


The fact that the curves "cross" at 5,252 means nothing, as each curve plots a different parameter using different units.


It's just a shorthand for calculation, resulting from using particular units for HP and Torque.


Power [in HP] = torque [in lb ft] X RPM/5252


If you used the civilized and scientific SI units, the factor is 9,549


Power [in kW] = torque [in Nm] x RPM /9549

If you expressed torque in lb in, again the factor would be different

Power [in HP] = torque [in lb in] X RPM/63024
I wouldn't say I was completely wrong I still stand by my thought process for torque and hp, one dealing with initial acceleration and the other top speed and acceleration afterwards. I agree as you indicated rpm cross over where torque and hp switch is a variable depending on the engine itself and not a constant that I thought it was.
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