Cars 101: Horsepower vs. TorquePosted: August 19, 2011
These specifications found on all cars, but many people don’t really know what they mean, even if they know what sorts of numbers constitute a lot or a little. There is a very detailed answer for defining each of these terms but this is Cars 101 so we will keep it simple and applicable to what most people can recognize.
Horsepower is “power”, or the amount of work done over a period of time. Torque on the other hand is a measure of force, rotational force, or how “hard” something twists. For the viewpoint of the driver seat though these two concepts can be viewed in simple terms as the following:
Horsepower: The actual speed potential of the car.
Torque: How hard the car pushes you back into your seat when accelerating. Torque is what allows a car to tow heavy objects.
This shows torque pretty clearly:
Different cars have different balances of each. For example, my dad’s diesel VW Touareg makes 240hp and 406ft/lbs of torque; when you hit the gas it gives you a really good push into your seat, but when you look down you will be going 40mph instead of the 60mph you thought it’d be.
To the contrary the current BMW M3 has 414hp and 295ft/lbs of torque. It won’t seem to pull that hard when you gas it, but when you look at the speedometer it will read 120mph when you thought you were at 90mph.
This video shows horsepower in action. The Lamborghini is designed purely for speed and has 632hp to get it up well past 200mph:
For the street it is torque that makes a car feel fun when you hit the gas. This is part of why I think most normal cars should be diesel powered; good driving feel and much more fuel-efficient. Horsepower is what gets makes a car fast though, that is why a lot of racing cars are very horsepower biased.
I should emphasize though, that this is a simplification of reality. While it will be good enough for the average person to understand, those of us who know more about the inner workings of a car and the physics involved know that there is more to describing the torque power relationship in how a car moves and feels.