What is the difference between HP and Torque

[TheSilentChamber]

Um yeah, thats completely wrong.

[Schister66]

http://www.geocities.com/MotorCity/7177/torquehp.html

There is also a discussion in the Street/Track Racing Section under Honda about the same thing.

[454Casull]

A horsepower is a unit of power. Torque is torque. Power is a function of torque and angular velocity. With the proper gearing, acceleration and top speed depend on power.

[TRACYCULBERSON]

Originally Posted by 454Casull

A horsepower is a unit of power. Torque is torque. Power is a function of torque and angular velocity. With the proper gearing, acceleration and top speed depend on power.

OK GUYS LETS RE GROUP.
read all the replys to this ? .. all say torque has somthing to do with acceleration, or your gear ratio. ok to any results out of gear ratio is for the real wheels to turn or the front what ever ok torque , sure it is A measure of force but the object has to move to get any amout of force. so forget it guys nothing you will say will change my theory of how you get deffinition. of what torque is . it is!!!!! the amout of horse power that is applied to the rear tires and to the pavement or vica versa if drive a front wheel drive . the guy dont want to no how u measure it but what is it . it is in all your replys but not in the right fase.

[curtis73]

Sorry, Webster disagrees.

Torque

1. The moment of a force; the measure of a force's tendency to produce torsion and rotation about an axis, equal to the vector product of the radius vector from the axis of rotation to the point of application of the force and the force vector.
2. A turning or twisting force.

Horsepower

1. Abbr. hp A unit of power in the U.S. Customary System, equal to 745.7 watts or 33,000 foot-pounds per minute.

Note that torque is measured in several ways, one of which is foot-lbs and one HP is equal to 33,000 ft-lbs/min. Technically, HP is torque over a period of measured time. Its an abstract thing, but torque is how much twisting force is being made at the crankshaft. Since torque is a static measurement and HP is a moving measurement, imagine HP as being the measurement of how many times or how fast that torque is being applied. If you could divide the 360 degrees of rotation into an infinite number and measure the torque at each one; that's horsepower. The faster it spins with the same torque, the more HP can be made.

[Moppie]

I think someone is smoking something they shouldn't

[Alastor187]

Originally Posted by 454Casull

A horsepower is a unit of power. Torque is torque. Power is a function of torque and angular velocity.

Finally, someone who realizes that this “Power vs. Torque” discussion is not limited to the U.S. customary system of units.

Horsepower vs Torque makes as much sense as Watts vs Torque, Power vs Pound-Feet, etc.

Originally Posted by curtis73

Note that torque is measured in several ways, one of which is foot-lbs and one HP is equal to 33,000 ft-lbs/min. Technically, HP is torque over a period of measured time.

Actually torque is measured in pound-feet (lb-ft), work is measured in feet-pound (ft-lb). Since work and torque are not equivalent, it cannot be said that power is simply torque measured over time (it is work over time).

To convert torque to power both time and distance are needed. Hence, RPM which has both a distance and time component.

It is this reason that torque by itself does not give any indication of an engine’s performance. At minimum torque and engine speed are needed.

As well, torque at the engine means little as it can be multiplied nearly indefinitely to the wheels. Of course the trade off of gearing is rotational speed or angular velocity, but the one constant factor is power.

[superchuckles]

sracing has it right. i think that it's just that some of you can't visualize what he's trying to tell you. horsepower & torque are two different viewpoints of the same equation regardless of how some of you seem to believe things are.... 1 horsepower is defined as the amount of energy needed to lift 550 pounds of weight a distance of 1 foot in 1 second. simply put, horsepower is the application of torque, over time, whereas torque itself is the amount of force generated by the twisting motion of an object, measured at a given distance (i.e. inches, feet, millimeters, what have you) from the center of the axis at a right angle. torque can be measured as either a static measurement (holding a given weight up) or dynamically as a peak potential quantity (i.e. max breakaway torque achievable @ a given rpm). it's really very concept to understand.

[Cait Sith Cat]

JESUS DON'T USE CAPS.

Please don't use all capital letters. It looks much better when you type normally.

And yes, that's why diesels tout potentially less hp than a big EFI counterpart, but puts out a load more torque: You might not get speed out of it, but you can pull more.

My inline 6 only has 145 hp (as opposed to 205 of my dad's 302 of the same model year) but it has the same torque, so we can haul the same load, he'll just do it with a bit more speed and ease.

[TheSilentChamber]

You get onto someone for using caps in a four month old thread? Both are equally annoying.

[Cait Sith Cat]

I was searching threads and saw this. Neither here nor there, and I did put relative info in the thread.

[TheSilentChamber]

Just dont confuse relative and useful.

[SaabJohan]

Torque is defined as the sum of force vectors around an axis (of rotation). Basicly that means than on an axle torque is the force that will try to rotate the axle. We can have torque and no rotation and torque with rotation.

Torque can be used to do work. Work is defined as force multiplied with distance.

Horsepower is one unit of power, according to international standard power should be measured in watt. Horsepower was used as a measurement since some of the earliest steam engines replaced horses to power water pumps used in mining. One horsepower was the mean power produced by an average horse.

Power can be defined in many different ways depending on the situation, if we talk about engines the most common definition is power equals work per time unit.

What makes a car perform is the engine power, not torque. For example to make a car accelerate you need the power, P:

P = Fv = mav

m = mass
a = acceleration
v = velocity

Power is also what makes the top speed of a car. In order to drive at a certain speed the drag (aerodynamic and rolling friction) must be overcome. With a drag, F, the power, P, to drive at a certain velocity, v, is:

P = Fv

In order to offer a high performance a high power output at a certain rpm isn't enough. Instead the maximum output in a certain range is required, for example 6000-9000 rpm. What range is required depends on the application, a four speed gearbox will for example require a better range than a six speed gearbox.

So if it's power that do the all important stuff, what does the torque do. Well, torque is what makes your clutch slip, it's also what can overload the gearbox. Basicly torque itself has no function, but it is required to develope the power. Sometimes "torque" is incorrectly used to decsribe the low speed performance of an engine. Even though it's incorrect use of "torque", an engine that is powerful already at low speeds tend to have a good "range".

[curtis73]

and with that description... this thread is closed. Too old for my tastes