Originally Posted by
danmartin Wrong. HP is a measurement of power. It is directly related to how long it takes to move a mass to a certain speed. Torque is a measurement of force (fun). HP wins races.
Look Dan, there's no need to teach these guys anything. If they want to be ignorant, desk engineers/racers then we can't stop them. Really, I would have argued the same point myself but didn't want to turn my own thread into a shit storm. But, since we're already knee deep...
When someone says something like "torque wins races" or "a racer would rather have more torque, given the same power output" or "torque is god/fun/gets me off on cold nights/will have my babies one day" etc. what they really mean is that producing larger amounts of horsepower at lower engine revolutions is better than producing less horsepower at lower engine revolutions. No shit Sherlock.
I'm going to end the debate on HP vs. TQ right now, today, once and for all. We can all understand horsepower. It's a measurement we can all relate to. I don't feel I need to explain it further, except to reiterate what Dan said. Horsepower does work over time. Horsepower is a measurement of power. How
fast something can be done depends on how much power you have to do it. Enough said.
Torque on the other hand is a measurement of force, specifically, the force used to rotate an object about some axis (or, keep an object from moving about some axis). This can't get anything accomplished on it's own. Let me say that again. Torque does
nothing. Specifically instantaneous torque does nothing. Without the time element, no work can be accomplished.
If you went to an immovable object sticking out of the ground and tried to twist it, you could exert all sorts of torque on it all day long, and it would exert the same amount of torque back. This immovable object is literally applying millions of foot pounds of torque to match your millions of foot pounds, yet it goes nowhere. Once you let go, it stops too. This means the torque isn't applied for any meaningful length of time.
Yes, torque may be what is measured directly from a chassis dyno, but it is instantaneous torque. There is no component of time in the measurement. Take my dyno graph for example. I'm making approx. 110 ft. lbs. of torque at 3,300 RPM. Throw that into the equation for HP and you get about 70 HP. If I made more torque at 3,300 RPM, I'd make more HP at 3,300 RPM. And that is what we're after, horsepower. Because of the way the equations work, having relatively high horsepower at low RPM equates to a high torque figure. Having relatively low horsepower at low RPM equates to a low torque figure.
High torque output just means "early" horsepower. Early horsepower is great in most racing competitions and conditions, but it is the horsepower that is getting the job done, or performing the work
quickly.
Those big rigs don't accelerate because they have 2,000 ft. lbs. of torque at 300 RPM, it's because they have 200 HP at 300 RPM (where most cars have 5 HP). Get over it.