torque vs horsepower

hey alls

i was wondering what is the difference between torque and horsepower?? and maybe what are the definitions of torque and horsepower. is it better to get a car with tons of horsepower or lots of torque?

thanks

Horsepower is the amount of energy your engine produces, while Torque is the amount of force that is exerted by that energy.


Torque is better for acceleration, and speed, while HP is how quickly it can be done.

I will try to put it in an easier way to understand the difference between horse power and torque in auto mechanism term. Since I assume most of you are more confuse about torque than horse power, I will try to cut the HP part shorter.

Horse Power is a kind of force that your engine produce to power the transmission. (It might seem like a turning power due to the force is being rotate by the mechanism, but you can use a horse to pull on a rope and get horse power that way.) The transmission transfer that power through a series of gear ratio to the wheel and mobilize the car.

There are different types of horse power, such as raw horse power and wheel horse power, where raw horse power is the power produced by the engine at the crankshaft. It is commonly refer to when it comes to manufacture spec of how much HP does the vehicle has. Wheel Horse Power is the power produce by the engine after a series of gear ratio transferring and end up at the last point, which is your drive wheel. The more HP the engine has, the higher speed the car can reach. There is a formula to conculate or describe HP, but I can't recall it at this moment, may be someone out there can post it up.

Torque is a kind of twisting or turning effort. It's value is commonly use as lb/ft (foot pound) and lb/in (inch pound). When you have two gears engage together and one gear is inputting effort to drive another gear (it is simply call the "drive gear" and "driven gear"), if the "drive gear" has less teeth than the "driven gear", then you will gain torque.

For example, let say gear A (drive gear) has 20T (T=teeth) and gear B has 40T. when you input 100 lb/ft of effort to turn gear A, you will gain two times the twisting effort (torque) at gear B which is 200 lb/ft. In this case, the gear ratio is 2 to 1 where gear A is the drive gear. The conculation is done by driven gear divided by the drive gear.

On the other hand, if the 40T gear is driving the 20T gear you will lose torque since the gear ratio is 0.5 to 1.

When you gain torque in the process of gear ratio, you will loose speed, but if you gain speed during the process, you will loose torque. Just remember this statement, "If torque is the gain, the speed will be the lost."

I hope this info can clear up the clouds for you guys. :flash:

torque is the "moment of force". it is the leverage around a point. so means that a car can pull away in a higher gear because it has a higher leverage to get the car moving.
Horsepower is the available force at any one time (im not to sure about this, so its betta u pay attention to Tofuboys explanation on HP)

there is a thread exactly like this in the engineering/technical forum under cars in general. check it out. texan has written a wonderful description.