BirdsOnly

James Watt, the man that first dubbed the term horsepower. He wanted to see how much coal the average horse could move per unit time. Just think if he would of used a donkey, we would all have 325 a.p. cars (asspower)

Arfdog

This made me actually LOL.

I am satisfied with all answers in this thread. It has my blessing.

justin455

^first post in a thread 3 1/2 years old...starting off well, I see.

Arfdog

You aint seen nothin yet! Just call me grave digger.

magnum-gto

I like to think of TORQUE as how big a hammer you pick for the job,...
the number of times you strike the nail is RPM.....

AND, the time it takes to drive a nail is HORSEPOWER.

Therefore you can select a big hammer and drive the nail with 3 swings......OR
you could pick a small hammer and drive the nail with 20 quick swings.

IF the time to drive the nail is the same for each example,....the horsepower is the same.

This is how a small import turning 10,000 rpm can match HP with a big inch motor
turning 6500 rpm.

Crude example but true.

Adrenaline_Z

Good example. For those still confused, just think that torque is a force

but Horsepower is just a measurement...a measurement of force over time.

I'm under the impression some people confuse horsepower as a force when
they say, "I'd rather have more horsepower than torque at xxx RPM."

joecar

Not just force over time, but force and distance over time: P = F.d/t = F.v

Also note that F = m.a, so P = m.a.v (i.e. instantaneous RWHP can be calculated from logging v while driving).

Adrenaline_Z

Right! You can apply all the force in the world, but if you haven't
moved any distance you have done no work.

This feels like highschool physics all over again.

bww3588

iTrader: (49)

thats incorrect....

if you push on a wall, you are doing work on the wall. just because the wall isint moving, doesnt mean your not doing work.

remember Newton's Law. (one of them) For every action there is an equal but opposite reaction.

Adrenaline_Z

Grab the Horsepower formula and view the result if the distance (RPM) is zero.

W = 1000 * 0
W = 0

HP = 0 RPM * 1000 / 5252
HP = 0 / 5252
HP = 0

95ONE

iTrader: (1)

FNG again. drumming up old *** posts. (for the other FNG's?)

A nameless quote, "There are engines that have lots of horsepower and torque. They are called race cars. There are engines that have lots of torque and some horsepower. They are called dumptrucks."

I'm sure this won't make me lots of friends here, but hopefully it gets some gears turning.

it's been said so many times here. But one more time. And hopefully I might say it in a way that lets some that haven't got it yet... get it. As basic as I had to put it in my own head to fully understand it. Horsepower is how fast a motor puts out torque. The more horsepower you have compared to a static torque number, the faster it is.

I had to break that simple thing up into 4 simpler versions. hopefully it helps others too.

Four different ways of viewing what kind of motor you want.

1 You can quickly put out lots of torque
2 or quickly put out a little torque
3 You can slowly put out a Lot of torque
4 or slowly put out a little torque.

Honestly the last two didn't sound very appealing. But factually the middle two are very much the same. If geared right as pointed out by many examples here. (taking revs into account but using that makes it confusing again) There are of course infinite variations but these are the most extreme to make the point.

I personally would be happy with a lot of HP and a medium amount of torque that revs high. (gearing makes up for torque - I road race.) But if I can have the best of everything, lots of hp and torque would be best. And so would being a rock star. Rich AND famous. It happens, but not often.

Crash7557

I read somewhere and it it my understanding that HP is a measure of the rate of acceleration of the engine. This is why horsepower increases as rpm increases as long as there is sufficient torque to resist the drag and imperfections in the engine. An engine at WOT is creating a chain reaction only interrupted by the rev limit or resistance/drag. The rate at which the reaction occurs exponentially increases as rpm increases until the engine cannot tolerate the forces applied.
Example: an aggressive cam coupled with forged parts for durability may produce more torque at a higher rpm therefore counter-acting the increased drag (both mechanical and environmental) at X rpm and allowing the engine to reach higher horsepower.