Torque

[Weichien]

hello bros.

can anyone kindly en explain to me what is torque, what is it for and what is the advantage and disadvantages.

[Mustank]

Dear all, pls enlighten me also....

 

my science study only up to sec 4 even then it was combined science ....

 

what is the difference between troque and horse power? is horse power a measurement of torque?

 

sorry for my stupid questions .....

[Nothingtodo]

http://en.wikipedia.org/wiki/Torque

 

http://en.wikipedia.org/wiki/Horsepower

[Elfenstar]

torque in its most simplified form is a rotational force. Torque is the force that gets a car moving.

 

Power is a measurement of how much work per unit of time that the torque is doing.

 

Think of screwing in a screw. torque is the force you exert to turn the screwdriver. Power is the distance the screw has gone in in X amount of time.

 

More torque is useful for faster acceleration or heaving loads that can be carried or pulled.

 

Too much torque can be bad as the tyres may lose traction if the tyres arent good enough or it may break the transmission/drivetrain if they are not strong enough.

 

Back to the screw... if you use a screwdriver with the wrong sized head you could "mushroom" the screw-head or if you use too much force after the screw is in, you may strip the thread.

 

Hope the explanation helps

[Elfenstar]

See my earlier reply.

[Weichien]

thanks bro.

but a higher torque is better or a lower 1?

some people explain to me using a rubber band stretching.

[Mustank]

sorry for my silly questions....

 

i also see nothingtodo's links already......but that one too chim for me ...

 

i still cannot see the differrence between horse power and torque....the reason why is bec i notice that when someone is describing a car, he will say troque got how much....and horse power got how much....

 

thank you for teaching me

Edited July 27, 2007 by Mustank

[Scaglietti]

Torque is basically the amount of turning force the engine can pull. Using the analogy of a cyclist pedaling a bicycle, it is the amount of force you apply on the pedal.

 

Power is the rate of torque being transferred to the drivetrain. It is like force applyed to the pedal x how fast he is pedalling.

 

Power(hp) = (Torque(ft-lb) X RPM) / 5252

 

Power is more directly related to acceleration. Compare a cyclist can apply a force while pedalling slowly and another applying the same force but pedalling quickly. Both are applying the same torque to the pedal. But the faster you pedal with the same torque, the more amount of work is delivered into the chains and then to the wheels, and the more acceleration you'll get.

 

The higher the power, the more acceleration you will get.

 

Torque will measure the responsiveness. The higher the torque at the particular RPM, the more responsive the engine at that RPM.

 

BC

Edited July 27, 2007 by Scaglietti

[Mustank]

pai seh to keep on asking ...

 

which is more impt for a normal car driver, hp or troque?

 

is it possible for a car to have high hp but low troque or a car to have low hp but high troque?

 

if it is possible, what are the characteristics of a car with high hp but low troque and a car with low hp but high troque?

 

thank you

[Scaglietti]

Both torque and hp are interrelated. Look at the equation below:

 

Power(hp) = (Torque(ft-lb) X RPM) / 5252

 

There are 3 parameters: power, torque and rpm. All are interrelated.

 

The specs given are just max torque @ rpm and max power @ rpm. For the full story, you've got to look at the torque and power curve.

 

Usually, you look are HP for acceleration and torque for pulling strength. For trucks and goods vehicle, the engines are usually design to give higher torque at lower rpm to move the load. On the other hand, race cars usually have max torque at higher rpm (which also means higher HP).

 

Higher torque you will move heavier load with ease (more responsive). Higher hp usually means faster acceleration (faster 0-100km/h timings).

 

BC

Edited July 27, 2007 by Scaglietti

[Elfenstar]

neither. A flatter torque curve (when the amount of torque is plotted against a graph) is what should be aimed for.

[Elfenstar]

Don't listen to scag. He doesnt know what he's talking about.

 

the difference between the two is simple if you take gear ratios etc out of the example.

 

Torque is the force that moves the car. Power is the measurement of how much work can be/has been done.

 

Using a simple example of hammering a nail. Torque would be equivalent to the force you use to hammer. The distance the nail goes in within a fixed time would be the power.

Edited July 27, 2007 by Elfenstar

[Elfenstar]

Did you read my reply in the other post??? Get your facts right.

 

Your equation is wrong because it is a conversion to convert ft/lbf to bhp. The actual equation is simpler. Power = Torque x rotational/angular speed

 

Power is NOT acceleration. It is reflective of attainable speed. Torque is reflective of acceleration. Acceleration at ANY point between max torque and max power is lesser than at max torque.

 

Even your bicycle analogy is wrong. everything else being equal, in order to pedal more quickly the cyclist has to use more force.

Why? because force = mass x acceleration. Assuming that the bicycle and rider weight 100kg's in total but one accelerates at A speed and the other b speed. it means that the force for one would be 100 x a the other 100 x b which means the force is different.

[Yc86]

Rubber band stretching?

 

I would love to hear it too..

[Scaglietti]

It is not as simple as you have put it...

 

You have forgotten that to convert torque to force at the wheels, you've got to take into consideration of the gearing and wheel size, etc.

 

I do know what I am talking. But, on a second look at my post, I do agree the statement was not phrase correctly. (Sorry for the misleading information.)

 

HP itself relates torque. Torque by itself cannot adequetly measure performance. Torque in conjunction with rpm (which is hp) tells you about performance.

 

Torque will tell you the responisiveness... the force that the engine is capable of applying to the drivetrain, the instanteneous acceleration.

 

BC

[Scaglietti]

Even your bicycle analogy is wrong. everything else being equal, in order to pedal more quickly the cyclist has to use more force.

Why? because force = mass x acceleration. Assuming that the bicycle and rider weight 100kg's in total but one accelerates at A speed and the other b speed. it means that the force for one would be 100 x a the other 100 x b which means the force is different.

That is not my analogy. In my analogy, force is constant, rpm is different. My mistake was the acceleration is more for higher rpm. You should get same acceleration for both scenerio. But the power is higher in the higher rpm.

 

Sorry!

 

BTW 100 x speed a and 100 x speed b is nor force... it's momentum.

 

By right all this equation is not sufficient. This are equations for instantaneos force/acceleration/etc. To be precise, you might need to use differential equations...

 

BC

[Elfenstar]

First things first... i said acceleration of speed, not speed so its not momentum now i can get back to it

 

Now torque is a better gauge of acceleration at any set point in the rpm. nothing can change that.

 

If you're looking across gears and cars all torque tells you is what the max force the car has BUT max power tells you the max amount of work that can be done. Not to mention that torque at the wheels is affected by gearing etc while power is constant. Thats why when using regression statistics, its a better overall performance gauge, however when done seperately for each gear, torque actually shows a better correlation.

 

Oh and if max hp is a better gauge to acceleration, can you explain why the USDM F20 S2000 posts a lower 0-60mph time (6.3 vs 6.5) than the USDM F22 s2000 which is identical except that it's engine produces more torque and the F22 has shorter gear ratios to increase the torque at the wheels.

[Pisces69]

Maybe I try.

 

More Torque is better acceleration & pick-up.

 

More HP is higher sustainable speed.

 

Did I get it right?