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Old 01-07-2011, 04:27 PM
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Default Difference Between Torque & HorsePower

What is the difference between torque and horsepower, and what benefits do each bring to engine power? Could you put that in layman's terms for the mechanically challenged, such as myself.

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Old 01-07-2011, 04:56 PM
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Torque is a measurement of a "moment of force" and horsepower is the amount of work that force can do over time. So, as it relates to a motorcycle, torque is the amount of energy generated by one power stroke (release of energy at the time of ignition and converted into mechanical energy) of the engine; and the horsepower is how much work the motor can do based on revolutions per minute times torque. This is why horse power trends up as RPM's rise and torque curves stay relatively flat.

Understanding why there is a torque curve is a bit involved though.
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Old 01-07-2011, 05:01 PM
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Horsepower is a measure of power, torque is turning force. Think of it this way, horsepower is what lets you fly down the highway easily at 85-90 mph and torque is what gets your fat *** carrying your passenger off the line at a red light.
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Old 01-07-2011, 05:21 PM
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At the most basic level:

Power = Torque x RPM

Horsepower is a unit used to measure power (Hp) as is Kilowatts.

Easiest way to understand it is to think of riding a bicycle.

2 riders of the same mass (weight) riding together at the same speed (mph). If they are riding at the same speed and the are the same weight on identical bikes they are both generating the same power (horsepower)

Rider one is a spinner, so he chooses a high gear and turns the cranks at a high cadence, but the resistance to turning is low

Rider 2 has strong beefy legs, so he pushes the pedals hard but doesn't spin the pedals quickly.

Rider 1 is generating power using high speed with low torque

Rider 2 is generating power using low speed and high torque.

Applied to a motorcycle, having good torque means you don't chop and change gears all the time, but for the same power and same gearbox this comes at the expense of top speed

It is a compromise that engineers have to live with all the time when designing any machinery
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Old 01-07-2011, 05:29 PM
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Torque gets you up to speed. Horsepower keeps you there. At least that's what I was told.
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Old 01-07-2011, 05:29 PM
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High dyno tq numbers are a warm blanket that most guy's cling to when arguing about who's bike is the fastest by comparing dyno sheets. Horsepower is what wins that race in the real world, a real race, not roll on in 6th gear at 50 mph.
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Old 01-07-2011, 05:31 PM
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Torque gets you up to speed. Horsepower keeps you there. At least that's what I have been told.
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Old 01-07-2011, 05:44 PM
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farm tractor may only have 15hp but because of the tq. it generate look at the power it has to pull a plow through the earth. bikes can have 180hp but can do no heavy work. my 2,3,4, cents
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Old 01-07-2011, 05:52 PM
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Think of torque as holding back a fart, letting it go is horsepower.
This explanation always made sense to me. LOL
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Old 01-07-2011, 05:53 PM
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Put in motorhome terms, horsepower gets you to the mountain and torque gets you up the mountain. Anyway................that's how I think of it.
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Old 01-07-2011, 05:53 PM
 
 
 
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