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Old 08-02-2001, 06:45 PM   #1
carman
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Horsepower vs. Torque

Definition of HP
Quote:
In Watt's judgement, one horse can do 33,000 foot-pounds of work every minute. So imagine a horse raising coal out of a coal mine as shown above. A horse exerting one horsepower can raise 330 pounds of coal 100 feet in a minute, or 33 pounds of coal 1000 feet in one minute, or 1,000 pounds 33 feet in one minute, etc. You can make up whatever combination of feet and pounds you like - as long as the product is 33,000 in one minute and you have a horsepower. You can probably imagine that you would not want to load 33,000 pounds of coal in the bucket and ask the horse to move it one foot in a minute because the horse couldn't budge that big a load. You can probably also imagine that you would not want to put one pound of coal in the bucket and ask the horse to run 33,000 feet in one minute, since that translates into 375 miles per hour and most horses can't run that fast
Definition of Torque
Quote:
Imagine that you have a big socket wrench with a 2-foot-long handle on it and you apply 50 pounds of force to that 2-foot handle. What you are doing is applying a torque, or turning force, of 100 foot-pounds (50 pounds to a 2 foot long handle) to the bolt. You could get the same 100 foot-pounds of torque by applying one pound of force to the end of a 100-foot handle or 100 pounds of force to a one-foot-long handle.
Similarly, if you attach a shaft to an engine, the engine can apply torque to the shaft. A dynomometer measures this torque. You can easily convert torque to horsepower by multiplying torque by RPM / 5252

hp= torque x RPM/5250

The torque produced by the engine is what is moving your car, and horsepower how fast its being produced.
If you see the equation, you have to increase either torque or rpm to make more power.


Every type of power delivery has advantages and disvantages , but for STREET USE, I found that torque is more useful than HP....

The S2000 is fast yes, but it's also a car that has to be revved like mad to get the 240hp, and to keep the engine at their peak operational rpm you need a close ratio gearbox, so you have to shift a lot...

The Viper is also fast, but with ample reserves of torque on tap, you can drive around easely and you can use longer gears that gives you better fuel economy.....
For example the S2000 vs M roadster:
S2000: a fast car but for you to enjoy the 240hp you need to reach 8500RPM, someting that you cant enjoy all day, and with such a small powerband you need a close-ratio gearbox, and with less than 160lb-ft torque you better have a light car like the S2000.
On the other hand we have the 240hp M roadster that produces 240hp@6000 but with 236 lb-ft @3800 RPM, both cars are similary fast off-line(even when the M is 300lb heavier) but really what car do you think is more easy and enjoyable to drive around(not the whole car just the engine), thatīs why Im asking if it worth something making all this sacrifices in order to get incredible hp/liter figures......fuel ecconomy is not an excuse since usually the big-displacement/lower revving engines sucks as much gas as the small displacement/high revving, in this case the S2000's 2.0 gets 20/26 mpg and the M roadster's 3.2 gets like 19/26 mpg.....so again why to bother???
Dont get my wrong hight-rpm hp low torque cars can be very fast , look at the Modena for example, but most of these cars weights at or less than 3000lb, so what happens when you have a 4000lb car, hey im the kind of guy who likes hot performance , a lot of comfort and a lot of luxury and this doesnt come in a 3000lb car so again for me torque is king!!!!

p.s. Besides you can make a hell of burnouts with massive torque!!!!
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