"HORSEPOWER" MYSTERIES EXPLAINED!!!
What a magic word it seems to be? Riders talk about it -it is only a matter of time before this word starts flying around at a biker hangout-, hotrodders want more of it, manufactures advertise it and magazines write about it. The question is, what is it? The real answer is that horsepower is just someone's fabricated method of measuring the rate of work an engine can perform.
That someone was 18th-century engineer James Watt. Watt invented the steam engines and set out to find a way of helping the public understand the potential of these newfangled devices. He decided to compare engines to horses. Through a series of tests in which draught animals pulled loads of coal, Watt determined that the average draught animal could pull about 22.000 pounds 1 foot in 1 minute. Then, for reasons that are not clear, the scientists are still argueing about it, he raised that weight by a factor of one-half. (My explanation: Watt used mainly dray horses, but sometimes donkeys were beneath; they could pull but they did not, the average value was even too low.) The resultant work -moving 33.000 pounds 1 foot in 1 minute (equal to 746 watts)- was deemed one horsepower, and ever since, horsepower has remained the standard by which the output of a combustion engine is measured. Okay, so that is were the term came from, but it still does not explain what power -no matter if measured in horsepower, puppydogpower, Dutchwindmillpower, seacucumberpower, only the basis would be different- really is.
Power is simply calculated by multiplying the force applied by the distance covered and the time required. In simple terms, power equals Force times Distance times Time. We take the torque output of the engine (force) and multiply it with the rpm at which it is generated (rpm includes both the distance and the time). The result is the power output at that engine speed.
As a result, the only way you can increase an engine's horsepower is to increase the amount of torque it produces (even the displacement like a Harley) at any given rpm. And that's it! There is no black magic, no secret tricks that work around that principle, no exceptions; it is simple, everyday, gradeschool math.
Just be thankful, that James Watt knew how to get his hands on a few good dray horses (let us forget the donkeys); otherwise, we all might find ourselves standing around our favorite riders hangout bragging about our bikes' Miniaturepoodlepower. That does not quite roll off the tongue as easily as Horsepower, does it???