what does torque mean!?!?!?

Explaination 1:

Torque = a dyslexic's version of talk; to chat, communicate, discuss, impart information in a verbal manner.


Explaination 2:

I have no idea, it's something to do with making things go round!


Explaination 3:

It's something lots of people go on about, alot. Usually ending up in some kind of macho-driven one-up-manship resulting in "my bike's better than your bike!."


Explaination 4:

See Explaination 3, but avoid such conversation because you are aware of the simple fact that complete ignorance of how your bike actually works doesn't necessarily make you a bad biker, or ruin the simple enjoyment of riding said lump of machinery!


Explaination 5:

See Explaination 2 but add the important fact that I have a thing called a 'Torque Wrench' - it has little numbers on it that I know are important = (A). These numbers are also printed in my workshop manual = (B).

I know when to appy (B) to (A) so that my rear wheel, and other important bits on my bike I dare fiddle with, don't fall off or break. This to me is the singular thing I actually know about Torque, and the only one I consider important for me.




In all, I hope that helps, if not, at least gives your brain a break from all thses intelligent people who are making my head hurt. :P

[ophic]

Originally Posted by BillyC

Historically, 1 Horepower, is the amount of work required to lift 33,000 lbs of weight, 1 foot in the air.

In how long? Horsepower is a measure of power, not work, so there needs to be time in there somewhere.

(In fact its one minute. 1HP = amount of power required to lift 33,000 lbs of weight, 1 foot in the air in one minute)

[BillyC]

K You're not helping

However you are forgetting:

Explanation 6:
Torque, a crappy film about bikes made by Hollywood.

[BillyC]

Originally Posted by ophic

In how long? Horsepower is a measure of power, not work, so there needs to be time in there somewhere.

(In fact its one minute. 1HP = amount of power required to lift 33,000 lbs of weight, 1 foot in the air in one minute)

Yes sorry, I missed that bit out however I feel I redeem myself at the mention of 550 foot-pounds-per-second. So 1 Hp is the ability to raise 550 lbs, by 1 foot, in 1 second. (Or 33,000 by 1 foot in a minute).

[ophic]

alright my turn.

Torque is the turning force than an engine produces. As RandyO says, it can be referred to as leverage. Now obviously an engine doesn't produce a smooth force but rather pulses of it as the cylinders fire. So I think of torque as the average turning force produced over one revolution of the engine.

So the more torque produced the more force the engine puts out so the faster we accelerate, right? Yes, up to a point. Revs also play a part as they determine how "often" the engine delivers its torque.

Now it gets a bit more complicated. As the revs rise, the engine produces more torque until it reaches its peak torque rpm - somewhere around 7000-7500rpm on an SV. Now after the peak, the torque produced actually drops off, but it does so gradually (at first). As the revs go past this point, the torque decreases but the revs continue to rise, meaning that the engine delivers less torque but more often. This increase in frequency more than compensates for the drop off in torque, so the amount of power delivered keeps on rising - up to the point where the engine is developing peak power. This is the real "sweet spot" of the engine and where you will find it accelerates the fastest.

After peak power the torque drops off more quickly than the increase in revs can compensate for, and hence the power output goes down and the engine is now past its best - at this point its time to cog it up a gear and start all over again

[sv4me]

Cant wait to see what didge makes of that

Originally Posted by BillyC

K You're not helping

However you are forgetting:

Explanation 6:
Torque, a crappy film about bikes made by Hollywood.

No, I deliberately left that out in an attempt to eradicate it from my memory - which you have now brought flooding back.

Oh the horror, the horror!

[ophic]

There are two ways of making an engine produce lots of power - you can increase its torque, or you can make it produce that torque at a high rpm. If my engine produces 60Nm of torque at 7000rpm and i wanted to make it twice as powerful, i could theoretically make it produce 120Nm of torque at 7000rpm, or i could make it produce 60Nm of torque at 14000rpm.

To make it produce twice the torque i'd have to double the size of the cylinders. Revving twice as high would keep the cylinders the same, but they would fire twice as often.

One way of thinking about it is to imagine the amount of fuel an engine consumes. Big low revving engines will consume a lot of fuel every rev. Small screamers will consume not much per rev but they'll do it very often.

[ophic]

Originally Posted by sv4me

Cant wait to see what didge makes of that

well it made sense to me

Originally Posted by Jp

Bigger engines = more torque (which means power is created lower in the rev range)

Sorry jp - this only partly right. It is the lower in the rev range bit which is not necessarily correct - where peak power/torque is made in the rev range is engine-dependent. There's no hard and fast rule.

Originally Posted by Jp

Less Cylinders = more torque ( a 600CC single cylinder will have a much longer stroke than a 600CC 4 cylinder engine) but it wont rev as high, hence less power due to Power = Toque * rpm.

Sorry again, but this bit is total bollox.

A Fireblade or R1 makes more peak torque than a Duke 999.

As for how Power & Torque relate to each other, see below (source: http://www.pumaracing.co.uk/power1.htm)

HOW TORQUE AND POWER RELATE

Let's imagine we have a pulley at the top of a mine that is 1 foot in radius - or 2 feet in diameter. At the bottom of the mine, at the end of a rope leading round the pulley is a bag of coal weighing 100 pounds. Instead of using a horse to pull on the rope let's connect an engine to the pulley - perhaps by bolting the pulley to the crankshaft of the engine.

In order to lift the coal we need to apply a torque of 100 foot pounds to the pulley because the coal is pulling down with a force of 100 pounds applied at 1 foot from the axis of rotation. In other words the Torque applied is the Weight times the Radius of the pulley. If the engine turns the pulley at 1 revolution per minute how much work is being done?

Well for each turn of the pulley the coal will rise the same amount as the circumference of the pulley which is 2 pi times the radius = 3.14 x 2 = 6.28 feet. So in 1 minute the engine will do 628 foot pounds of work. Copyright David Baker and Puma Race Engines

We can rearrange the above in terms of torque and speed:

The rate of work being done (or Power) is Force x Distance per minute = Weight x radius x 2 pi x rpm foot pounds per minute. However we already know that Weight times Radius = Torque so we can equally say:

Power = Torque x 2 pi x rpm

To turn this into Horsepower we need to divide by 33,000. Our final equation therefore becomes:

Horsepower = Torque x 2 pi x rpm / 33000 which simplifies to:

Horsepower = Torque x rpm / 5252.

This is the universal equation that links torque and horsepower. It doesn't matter whether we are talking about petrol engines, diesel engines or steam engines. If we know the rpm and the torque we can calculate horsepower. If we know horsepower and rpm we can calculate torque by rearranging the equation above:

Torque = Horsepower x 5252 / rpm

Hopefully you can also see that when an engine is turning at 5252 rpm, its torque and horsepower figure is the same. Next time you see a graph of the torque and horsepower of an engine check to see that the lines cross at 5252 rpm. If not then the graph is wrong. This only applies of course if the power is being measured in horsepower and the torque in foot pounds and both lines are shown on the same axes. There are many other units in which torque and horsepower can be measured - for example power can be measured in Watts and torque in Newton metres. Unless we need to convert to such continental measures we can usually stick to horsepower and foot pounds.