Torque vs Horsepower

Filed in archive Learning on December 29, 2006

Just about everyone knows of (or at least has heard of) horsepower. It's the amount of power an engine has. It's a huge selling point for performance vehicles. More is usually better, until you run out of traction. But that's a story for another day.

So where does torque fit in? Well, torque is the delivery of power. How quickly you accelerate is proportional to how much torque you have to transfer the available HP to the ground.

That's why you accelerate much harder in first gear than in sixth. In both gears you're producing the same HP, but first gear is producing far more rear wheel torque.

Acceleration at any given speed comes from the amount of power, and most power is used in aerodynamic drag when at speed. So even if you had direct drive and it had a flat torque curve it would still accelerate much slower at higher speeds because of drag.

Here are a few different ways of looking at the differences:

Horsepower is the amount of power you have available (the motor).
Torque is how well that power is transfered into motion (the drive train).

Horsepower sells (it's what you buy).
Torque moves (it's what you feel).

Horsepower is how strong the punch is from a boxer.
Torque is how quickly (how many times per minute) he can hit you.

Please comment and leave your thoughts about it. HP vs Torque is highly Esoteric and the more info available, the easier it will be to understand.