Physics Lesson – Calculating Torque and Power From Datalogs



Remember this datalog?  The IAT temperature drops at the top end on the road whereas this does not happen on the dyno.  This may be the reason for the difference in the torque curves.
My virtual horsepower plot versus an actual dyno plot of the car.  It’s apparent the data could use some more processing though the overall trend is correct.
I had datalogs from my old Evo still on the hard drive, so I plugged those into my spreadsheet to see how they plotted out.  I used a sample rate of 5hz, or data every 0.2 seconds.  It looks pretty good compared to the real dyno of the car.  Again, notice the difference between my road dyno plot and the actual Dynojet plot in the upper RPM range.  My guess is that this is due to a combination of cold air and maybe a mild ram air effect from the car traveling over 60mph.  That snorkel for the stock Evo airbox is there for a reason! 



    1. You are absolutely correct, thanks for catching that! Should have been: Force = Torque / Radius

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