The difference between horsepower and torque

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Horsepower and torque--forever intertwined due to our undying love for all that is internal combustion. Do you really know what the difference between the two is, though, and is one actually "better" than the other? A younger version (no gray hair yet) of Engineering Explained host Jason Fenske sits down to walk us through the difference between the measurements of power.

If you're unable to press play at the moment, here are the basics. Torque is a rotational force. Related to an engine, it's produced by the rotating crankshaft. Here in the States, we measure that force by pounds-feet or lb-ft. Our overseas friends prefer Newton-meters. Related to torque is work, which is the result of a force acting over a distance and is measured in foot-pounds.

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Horsepower, on the other hand, is a measure of the time it takes to perform work as defined above. The original measure of one horsepower comes from Scottish engineer James Watt, who found that a working draft horse could produce work at a rate of 33,000 ft-lbs per minute. So one horsepower equals 33,000 ft-lbs.

Now, to relate torque to horsepower, the math shows that horsepower and torque are equal to one another at 5,252 rpm. Above that, horsepower is greater than torque. Which is more important to you should depend on your needs. A torquey truck can pull a heavy load but post a slow 0 to 60 mph time. A high-horsepower sports can can zip though a 0 to 60 mph run, but if you weigh it down it struggles.

Some say that horsepower sells the car, but torque is what gets it moving. Others believe that horsepower is the key to winning races.

All we know is that both are important, and the video above spells it out better than we can thanks to an actual understanding of math and physics.

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