Best Engine Power

[wailunwu]

HI

Assuming even distribution of fuel and air in the engine, why is peak/best engine power not at peak EGT (with stoichiometric fuel to air ratio 14.7 to 1)? I was told that best power is at a slightly rich fuel to rich ratio.

If 14.7:1 gives the most efficient combustion (with no excess fuel/gas) why doesn't the engine power peak at this point?

Please see link below:
http://www.mummbrothers.com/SRF_Stuff/images/Stoich.gif

Thanks
Al

[Sokol]

Hi Wailunwu,

please post the source for your image. And specify the kind of engine.

[rwm]

There is a difference between best power and what is best for power. If you run your engine leaner, it creates more heat, and more power, but heat is dangerous and not good for longevity. So running a bit rich to keep temperatures lower is best.

This explains it pretty well. Air/Fuel Ratio tuning:Rich vs Lean | Turbobygarrett (http://turbobygarrett.com/turbobygarrett/airfuel_ratio_tuning_rich_vs_lean)