What exactly is horsepower?
Thread Starter
Pro
Joined: Dec 2000
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From: Camino CA
What exactly is horsepower?
I know all about torque and why it's a good measurement of power. But I never learned what horsepower really is a measurement of, and what the difference between HP and torque is. What is it?
Melting Slicks
Joined: May 2001
Posts: 2,700
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From: Lebanon KY
Re: What exactly is horsepower? (Ben Taylor)
The definition of horsepower, scientifically speaking is:
One horsepower is the work done at the rate of 550 foot-pounds per second and it is equivalent to 745.7 watts.
SO in english....the amount of energy required to lift 550 pounds, one foot, in one second
http://www.revsearch.com/dynamometer...orsepower.html
[Modified by corvettemaster, 8:03 PM 6/18/2002]
One horsepower is the work done at the rate of 550 foot-pounds per second and it is equivalent to 745.7 watts.
SO in english....the amount of energy required to lift 550 pounds, one foot, in one second
http://www.revsearch.com/dynamometer...orsepower.html
[Modified by corvettemaster, 8:03 PM 6/18/2002]
Melting Slicks
Joined: Dec 2000
Posts: 2,635
Likes: 0
From: Union Ontario
Re: What exactly is horsepower? (corvettemaster)
http://www.howstuffworks.com/horsepower.htm
Check out the shortcut, it explains it very well, better than most textbooks
Check out the shortcut, it explains it very well, better than most textbooks
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: What exactly is horsepower? (Ben Taylor)
Hp is the product of torque and rpm. 1hp=33,000 ft-lb/minute.
On a historical note that figure was obtained in the 18th century in England by observing a horse hoisting freight. It was observed an average horse would vertically lift a 150 lb load at 2.5 mph. Without doing the math figures out to about 33,000 ft-lbs/minute. Back to TV :lol:
Scott
[Modified by Scott78, 7:01 PM 6/18/2002]
On a historical note that figure was obtained in the 18th century in England by observing a horse hoisting freight. It was observed an average horse would vertically lift a 150 lb load at 2.5 mph. Without doing the math figures out to about 33,000 ft-lbs/minute. Back to TV :lol:
Scott
[Modified by Scott78, 7:01 PM 6/18/2002]
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: What exactly is horsepower? (Ben Taylor)
Horsepower is the thing you brag about at the bar. The more you drink the more your car magically gains horsepower. :lol:
As automotive engines are concerned, horsepower is strictly a calculation, not a measurement. All dynos only measure torque. Then you use that figure to calculate horsepower. The formula is torque*RPM/5250. An example would be if an engine has 400# of torque at 6500 it would have 495.2 HP.
That would be 400*6500/5250=495.2
[Modified by Pete79L82, 7:15 PM 6/18/2002]
As automotive engines are concerned, horsepower is strictly a calculation, not a measurement. All dynos only measure torque. Then you use that figure to calculate horsepower. The formula is torque*RPM/5250. An example would be if an engine has 400# of torque at 6500 it would have 495.2 HP.
That would be 400*6500/5250=495.2
[Modified by Pete79L82, 7:15 PM 6/18/2002]
Safety Car
Joined: Feb 1999
Posts: 3,631
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From: Fountain Hills AZ
Re: What exactly is horsepower? (Ben Taylor)
As it relates to engines, horsepower is the combination of torque and rpm. At a given rpm, the more torque there is, the more horsepower there is. Or, looking at it another way, at a given torque figure, the higher the rpm, the higher the horsepower.
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Melting Slicks
Joined: Feb 2000
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From: Vancouver BC, Canada
Re: What exactly is horsepower? (89formula)
simple:
Power (hp) is the rate of change of energy (torque)
detailed explanations or examples can make the concept harder to accept. just keep it simple.
Power (hp) is the rate of change of energy (torque)
detailed explanations or examples can make the concept harder to accept. just keep it simple.
