Difference between power and torque

[leo_26782]

I guess the title says it all. I have never seen something that conviced me, could someone do better PLEASE?

[Evo]

That is a saying that goes something like " HP is the speed the speed that you hit the wall, torque is how much of the wall you take down.. "

Someone might explain it even better

[findleybeast]

horsepower is a function of torque. a way to think about it is that torque is power per revolution, but horsepower is power per second.

equation for horsepower
(Torque x Engine RPM) / 5252 = Horsepower

more info
How Stuff Works

[racer_f50]

Torque is rotational force.
Power is the work/time produced by the torque.

quite simple, but very hard to tell in terms of what you feel in a car.

a quote i've seen before on some forum "Power sells cars, torque wins races". not sure how true that is, though.

i guess a practical example is comparing trucks to sports cars. say you have a big deisel truck, it will be able to pull a lot of stuff because it has more torque, but it isn't very fast. whereas a powerful sports car (with less torque than the truck we're using) won't be able to pull much stuff (compared), but is a lot faster.

[mindgam3]

torque is what actually makes the car move - its the force that rotates the driveshaft

power is how much work is done by the engine per second.

Two engines can have the same power, but one can be high torque, low rev, and the other low torque, high rev.

With NA engines, for a given capacity, you usually have to have a trade off between the two

[ikon2003]

I recommend the HowStuffWorks website. It will do a much more thorough job at explaining the phenomenon than most ppl will put into a thread.

*disclaimer: while the physics may not be all that tough (the simple concepts of force and power), conceptualizing them does get a little tricky. That's why it's such a convoluted issue for so many people. I hope you get a good understanding of it, cuz that alone will put you above many so-called car enthusiasts.

[DeMoN]

more torque = faster 0-60 times
more HP = faster 60-## times.

[ZfrkS62]

a quote i've seen before on some forum "Power sells cars, torque wins races". not sure how true that is, though.

98% accurate. other 2% is applied to diesels

Torque gets you going, HP keeps you moving.

It's Ricer vs Muscle car.

All these spun out Civics all produce horsepower but have no torque to use for acceleration. Whereas RC45's Corvette has the torque to blow the doors off the civic off the line AND the horsepower to keep the rice rocket where it belongs..waaaaayyyyy in back

[Evo]

[quote="ZfrkS62"]

a quote i've seen before on some forum "Power sells cars, torque wins races". not sure how true that is, though.

Think Henry Ford said that.. I might be wrong though. or was it Shelby

[leo_26782]

Thanks for all those answer. I'll try to resume it , to see if someone starts screaming:

-Power is a function of what the motor uses to advance a certain distance
-Torque is a function of what the motor uses to make a certain weight advance

And the relation between both is very close: if you have the curve of one, you can find the other.


Does it mean that it is torque that makes wheel spin, while power gets the car going fast?

[ZfrkS62]

Does it mean that it is torque that makes wheel spin, while power gets the car going fast?

Yes. because if you look at the torque curves, you'll see that peak torque is at a much lower RPM than peak HP. Usually the launch point is just a bit under that.
If you want proof of that, just power brake a Chevelle

[mindgam3]

In simple terms, this is a good example. Torque is basically a force, but applied to a circular motion.

Imagine pushing a box across the floor. The amount of force you put in (or how hard you push it) determines how fast the box will accelerate.

The amount of power you produce is how far you push the box in a certain amount of time.

I.e If you move the box 10 metres in a second, you will be producing more power than if you only moved it 5 metres in a second.

Hence this is why, if you are producing more rpm (distance moved per second), the chances are you will be producing more power

[stephen_schwitters]

HP is the bottom line in terms of performance. Torque is one way to make HP, revs is the other. The problem with revs is that the engine needs to be tuned for good running at those high rpms, and so it suffers in the low rpms. Varible camshaft, and intake systems help with this alot, and a a real blessing to gearheads like us. I really think that if you had a high HP motor, it wouldnt matter how much torque you have as long as it is consistant, (not all at one small rev range)

[caneswell]

What he said ^^^^

[Pokiou]

Power is waht your engine putsout
torque is how easly it makes it come out ..

using this, Power = 10litres
torque = 100 cups to make that 10 litres...


thats as basic as i can explain it

Pok