Monday, December 1, 2008

The Story of Horsepower vs. Torque

This post is a followup to my previous post about the SAAB Youtube video. Actually that video no longer appears on the SAABUSA website, and the ad agency that produce the video no longer works for SAAB, so sorry if I made it look like an official SAAB video.

Anyhow, how did this trumped up controversy ever get started about torque and horsepower? Here's a bit of scientific and historic background.

You want to see the ultimate torque monster engine? Check this Youtube video.

Think of a hamster versus a horse. Which one has more power? You're right if you said horse. Which has more torque? If you put the hamster in a hamster wheel, you can measure torque. Put a horse in a similar wheel and you also have torque. The maximum torque is the measure of the weight of the hamster times the radius of the wheel. True even if the hamster is asleep but strapped to the wheel. Same with the horse. But if the hamster's wheel is 60,000 times bigger than the horse's, the hamster will have more torque. The horse will always have more power than a hamster regardless of wheel size.

Torque does NOT take speed into account. Strangely enough, acceleration does not measure speed either. You can have acceleration even if a body is motionless! For example, when the light turns green at a drag strip, acceleration immediately can go to maximum at the same instant that the car begins to move. Speed increases throughout the race, but the acceleration is at about its maximum before the car even crosses the starting line, and actually stays pretty constant throughout the race. (Say about 1.2 g, which is one way of measuring acceleration)

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