Thursday, November 8, 2012

Horsepower 101 - Giddy Up!

With Melbourne Cup this week and spring carnival season in full swing, everyone's talking horses. So naturally it makes us think of cars. I mean, what's a car, but a modern, shiny horse?

The word horsepower is most commonly used to measure a car's power output, but it was actually first developed to describe the output of steam engines. Back in the late 18th Century, the engineer James Watt was observing the draught horses at his local mill (or it may have been a coal mine – the jury’s still out on that bit of history). He concluded that a single pony could do 33,000 foot-pounds of work per minute. That means it could haul 1000 pounds of weight 33 feet in one minute. Or 330 pounds 100 feet in one minute. Or any combination of feet (distance) and pounds (weight) that multiplied to 33,000. So one horse equals 33,000 foot-pounds of power.

And thus a new unit of measurement, horsepower, was born. It has since been expanded to include all types of engines from steam trains to lawnmowers to garbage disposals. ‘Brake horsepower’, which you would have heard bandied about on Top Gear, is simply a measurement of horsepower before the loss in power caused by the gearbox, alternator and other auxiliary components. Think of it as ‘pure horsepower’.

So now we know where the term horsepower comes from, what does it mean in terms of performance?

An average sedan has between 110 and 150 horsepower. Imagine you have 150 horses tied to the front of your radiator, pulling you along. More horses mean more power, but you also need to know the weight of the vehicle they’re pulling to determine performance. A car is considered ‘high performance’ if it has a lot of horsepower relative to the weight of the car. For example, a Ferrari 355 F1 packs 375 horsepower and weights 2975 pounds. A Ford Escort is only slightly lighter at 2470 pounds, but has only 110 horsepower, less than a third of the Ferrari’s. So it’s a no brainer right? We’ll go for the Ferrari. Although there is one other variable we forgot to mention…price!

So now that you have the low down on horsepower, you can save yourself from all those endless race-day conversations about wet turf! It’s spring carnival small talk you can’t get wrong! For used car buying you can’t get wrong, visit

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