car question: torque v. horsepower

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dividend

I think there are some people here that understand cars so I'll ask this question here...

I've checked a few sites online, asked some ppl around, nobody seems to really know the exact difference between the two (torque v. horsepower)... is there a clear definition that can define them?

the dictionary says -
torque is twisting force.
horsepower is how much a horse can pull... (something like that)

that doesn't help.

My guess is torque defines acceleration, and horsepower defines max speed... would this be correct?

Thanks.
 
From what I understand HP is the amount of raw power the engine will produce, while torque is the measure of the total force that spins the wheels.

So 2 identical engines producing producing 300HP, in different cars, will produce different amounts of torque. Factors such as weight, traction ,wheel base etc... will cause these variations.

P.S. I think
 
Not a car person, but torque is the bit that defines how much your horsepower can do in terms of dragging stuff, doing the "big" work of trucks, industrial machinery, and effectively using horsepower through a given rpm range.

Torque is why some hotted up cars tear their diffs off, why funnycars "bounce" a little when taking off, and why tiger moths turn very fast in one direction and not the other.

Yeah, i dont think your far off, torque is a description of how "weighted " your horsepower is i suppose, how much "work" the horsepower can do, in terms of applying that grunt to the ground if you like.
Suberbikes, F1cars, have tonnes of horsepower (lots of torque too) but id like to see them towing a trailer full of cement, in first gear, up a 35% gradient.

Your average farm tractor could do that no probs, probably at close to idle, the other examples not so effectively.
 
http://en.wikipedia.org/wiki/Torque

Relationship between torque and power

If a force is allowed to act through a distance, it is doing mechanical work. Similarly, if torque is allowed to act through a rotational distance, it is doing work. Power is the work per unit time. However, time and rotational distance are related by the angular speed where each revolution results in the circumference of the circle being travelled by the force that is generating the torque. This means that torque that is causing the angular speed to increase is doing work and the generated power may be calculated as:

POWER = TORQUE X ANGULAR SPEED

Mathematically, the equation may be rearranged to compute torque for a given power output. However in practice there is no direct way to measure power whereas torque and angular speed can be measured directly.
 
Here's a good comparison I just thought up - a weed-whacker vs. a log splitter.

A weed whacker needs to spin fast, but doesn't need much "muscle" behind that fast spin - weeds aren't that tough. Therefore one uses a high torque low HP engine.

You don't want a fast-moving log splitter cuz you'll get some nasty injuries, but you do need a lot of muscle in the engine - so you use a low torque but high HP engine.
 
What you want is a constant torque at any RPM.

Try Nissan "Maxima", I belive its engine won best engine award 10 or more years in a row. You never have to step on it to fill the mussel. All you fill is pure mussel at all the time.
 
Quote from balda:

What you want is a constant torque at any RPM.

Try Nissan "Maxima", I belive its engine won best engine award 10 or more years in a row. You never have to step on it to fill the mussel. All you fill is pure mussel at all the time.
More...

Doesn't all that mussel kinda stink after a while?
 
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