Engine speed, torque, power and... nitrous?!

I have been thinking a lot lately about the simple relationship between torque, speed and power. To clarify:

• Torgue = turning moment = "twisting" force
• Speed = the angular velocity of the crankshaft = the "rpm" your car displays (not its actual moving speed)
• Power = rate at which work is performed = how fast your car goes = all that men care about

There is a constant battle between speed and torque in the design of engines. They both together produce power, but are inversely related. Increase speed and you decrease torque. Increase torque and you descrease speed. Increase both and you increase power. In Layman's terms they are annoying.

I have a vested interested in nitrous oxide injection, what man doesn't you might say. When I was 17 I designed a progressive nitrous controller for my A level technology project, and became obsessed for about a year until my insurance company eventually convinced me my dreams could not become reality. Why am I talking about nitrous injection? Float around on forums and websites that discuss the use of N2O injection and you will find claims that the systems actually REDUCE engine fatigue (wear and tear). Madness you might say, or is it?

N2O injection massively increases an engines torque, and supposedly more so at lower engine RPMs. The proponents of N2O injection argue that running the engine at lower RPMs with nitrous does not cause as much damage as running the engine at higher RPMs without nitrous. Paradoxically most users would inject their N2O throughout the rev range, unless they are smart and have a controller...

Now I am not about to debate nitrous, no no no. Let us revisit the relationship between speed, torque and power... except lets throw in engine fatigue into the mix. Given all other conditions being equal, does an engine fatigue more at lower RPM and higher torque? Or is more fatigue experienced by a higher speed with less torque?

Is gently tapping something with a hammer lots of times better than beating the hell out of it a few times?

A few questions spring to mind.

• Does the greater revving engine actually produce more friction?
• Is a greater force experienced less frequently more potent than a weak force experienced often?
• Are the nitrous people bullshitting us?

I think this would be a very interesting research project, and is obviously an area not entirely understood by engineers. In fact is there anything fully understood by engineers?