Air Fuel Ratio or Timing for Peak Power

[WeathermanShawn]

I know this is a fundamental tuning question that has been throughly discussed over the years.

Does anybody have any sound research results that definitively proves that adjusting Air Fuel Ratio (AFR) to an ideal figure gives better results than adjusting timing, or is it vice versa? Some of the literature from Greg Banish and Innovate Motorsports seem to insinuate that finding the 'fastest flame speed' for gasoline (~.9 lambda), then finding the correct cylinder pressure through timing adjustments is the route.

I have not been to the dyno in about a year, so I have spent the last week doing some street runs using various combination of AFR and Timing. I have logged runs using AFR's from 12.2-13.1 and timing adjustments of +3-4 degrees at WOT. While the mixture near 12.5-12.7 did seem to reduce knock, the technical literature seems to discredit the cooling effect of richer mixtures and suggests that you are simply burning less oxygen..hence you may get less knock but you will have less power.

Any thoughts?