What Exactly is Horsepower?

OK boys, admit it. Do you actually know what horsepower really is? It is bandied around in car conversation but how many of you would feel comfortable answering an exam-type question on it?

If you think you could, congratulations - you are a true car nerd. If not, read below and never feel left out of car conversations again!

In order to understand horsepower properly, it is probably best to go back to the very beginnings of it. Back in the day, before they had engines, the noble horse was made to carry people around and do all the heavy lifting. But then some wonderfully clever scienitists came up with the steam engine which would be able to make machines to replace the role of the horse.

At this time, machines were probably very space age and people couldn't understand them and how they were useful so in order for the scientist's marketing department to be able to sell the idea to people (OK - they didn't have 'marketing departments' back then but you get my drift) they decided to compare the machine's power to something that everyone understood - the horse.

James Watt (the same Watt that is on your lightbulb) came up with a calculation that horses do 33,000 foot pounds of work per minute. Yes, that is a slightly confusing measurement and is probably one of the reasons horsepower is so, but if you are asked the question in a table quiz now you know!

With this measurement, James was able to compare the power coming out of the engine to a horse. Then, when he was selling the idea to people he was able to say "This engine has the same power as 50 horses" or 50 horsepower.

For some reason this obscure measurement has stuck as a way of measuring the power of car engines today and has left car lovers all over the world scratching their heads.