Chaotic Bliss

Can someone give me a technical explaination as to why running lean (or running rich) can be damaging to the engine?

Also, can someone explain how adjusting the A/F ratio can increase power?

Thanks!

BillP

Running lean (too little fuel for the amount of air) can lead to detonation. Detonation is the uncontrolled explosion of fuel/air mixture. Under normal conditions, the fuel/air doesn't explode, it burns. By exploding (detonating), high pressure can damage plugs, valves, burn holes in pistons, etc.

Running rich reduces power. Why? Because "more isn't better". Too much fuel reduces the rate of burn, meaning less fuel is converted into energy (and lots more goes out unburnt). That costs you fuel, and can foul spark plugs, ruin catalytic converters, etc.

By adjusting the A/F ratio to the optimum number, you get performance and better fuel economy. The hard thing is to optimize it under all conditions (wide open throttle across all RPM as well as partial throttle, closed throttle at all rpm, and dynamic changes such as suddenly opening or releasing the throttle, under varying load).

Chaotic Bliss

Thanks. That is what I was looking for.

So with tuners like the Predator, don't they only adjust WOT A/F ratios? Does this mean there is no increase in performance during part throttle acceleration?