TTapsale

Can anybody explain horse power vs torque?

PorTTland

like MichaelTT pipes up with a cogent explanation.<ul><li><a href="http://www.howstuffworks.com/question622.htm">Some Answers at howstuffworks.com</a></li></ul>

John CC

at the very basic level HP = RPM * torque (in ft-lb) / 5250

efudd105

The way I understand it, torque is twisting force, while horsepower is work done; force per given unit of time.
At the track, horsepower is trap speed while torque is e.t.
Or is it the other way around?

MichaelTT

It explains the relationship of T to HP clearly (in tech speak) but does come down to very basic question of source of the definition for each...and THAT is a course onto itself. So 'howstuffworks' is a good source to start with...

TTerrell

Hp e gude when you headed straight and gota get top end from at er dang ding macheeen.

tork e gude when you twistin an turnen and slowin and goen... tork is reeel gude wen ya aint nowen what ya mat runinta...

made sense to me! But I speak the red neck...

0TT0 BURNER

Horsepower sells engines, torque wins races.

ChrisTTiaan

hahahaah

PanTTher

Torque (also known as a moment) can be described as the force exerted on an object off-center to rotate the object (or anything) about an arbitrary axis. Suppose I wanted to open a bolt.... If I were to exert 25lbs on a wrench handle that is 1-foot long I would be exerting 25 ft-lbs of torque or twisting (turning) moment to open the bolt. Suppose the bolt is kind of rusty and it's very hard to turn... As the bolt rotates you are still exerting a good deal of force on the wrench to make the bolt turn... You're expending energy to open the bolt... this is also called work. You're working very hard to make the bolt turn. The rate at which you are doing or can do the work in seconds, minutes or hours can be directly correlated to Horsepower. By definition 1Hp = 550 ft-lb/sec = 33,000 ft-lb/min. If you were Superman or Arnold Shwarzenegger and opened the bolt in 1/100th of a seconds you just generated 25 * 100 (ft-lb/sec) / 550 (ft-lb/sec) / Hp or 4.5 Hp.

Now the ability or capacity of an engine is measured by the time rate at which it can do work or deliver energy or the capacity of an engine is rated by its power which is defined as the time rate of doing work.

Lets look at a one cylinder IC engine example... The engine is comprised of a piston, connecting rod and crankshaft. In the combustion stroke the fuel and air get mixed and compressed. As the mixture combusts energy is released in the form of heat (lots of it!). As heat energy is released the gases expand (laws of thermodynamics) creating a massive pressure (2000 or 3000 psi) in the combustion chamber which in turn accelerates the piston down. Since the piston's path is fixed and the connecting rod is connected to the crankshaft and it can only move in circles the heat energy from the combustion is transformed to mechanical energy or work with some losses here and there. The combustion process exerts a net force on the piston which in turn transfers that force through the connecting rod to the crankshaft (off-center to it) creating a moment or torque. This moment is large enough to propel your car.

The higher the heat energy in the combustion process at low or high engine rpms the harder and faster the piston will be forced to travel and in turn generate power and therefore a larger twisting moment or torque.

Feel free to pitch in or correct me John S. or SmallTTs

gaTTmobl

like breaking loose bolts. torque is turning force to break a stopped one. horsepower is anywhere along the curve after its moving.