Jabba

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.

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.