HP vs Torque

I think that a lot of the confusion about power and torque arise from the fact that many years diesels were marketed to commercial users who wanted to know how much usable power they had and were smart enough not to fall for lies. The carmakers got away with all sorts of games rating gas engines. Even today in every dyno test that I have seen comparing the two the diesel gets much closer to its rated power than the gas engine. The diesel sometimes even exceeds its rating. I am convinced that there is something going on with the relative ratings systems. I was looking at portable band saws a while back and the literature advised that the saw needed about a 20hp electric motor, or a 30hp diesel or about a 40hp gas engine to operate well. There is no reason for this other than the ratings systems used. Another factor is that gas engines are designed to use more RPM to deliver the power. I have found high RPM to be unpleasant so I never get rated power from the gas engines that I have owned. However, the newer engines are much smoother and less objectionable to listen to at rated speeds so they are getting better.

Bottom line is that for a given tire size it is the torque AT THE DRIVE TIRES that make you move. The tire DOES NOT KNOW if the torque is coming from a diesel turning 1800rpm in 6th gear or a gas engine turning 6000rpm in 2nd gear. Either way it is power divided by speed gives you thrust. My diesel tractor has tremendous thrust at 3mph but my gas truck will easily outpull it at 20mph.