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Excellent set of articles thus far. Thank you very much, Mr. Vizard!!
The part about the red-hot intake valves hit me hard, though. Just to clarify, I'm generally more interested in the subject of lower BSFC's and better fuel efficiency than getting extra horsepower. A guy on the 'net known as Metric Mechanic grooves the face and back side of the intake valves to aid in fuel vaporization. Consequently it also has an effect on the boundary layer that can increase low-lift flow by about 5%, but that doesn't seem to be the predominantly positive factor.
An engine with the "Surface Turbulence" valves installed needs as much as 20% smaller jets (when installing the ST valves, they also reduce the main's by that much). The engine acts like it's running rich if the fuel isn't cut back. I would assume that the increase in surface area on the chamber side of the valve would cause it to pick up more heat from the combustion process, while the grooves on the intake-side of the valve would help the valve dump more of that heat into the incoming air/fuel charge. The required ignition lead is reduced and detonation limits are stretched.
Assuming this is true, could the 20% reduction in fuel be due to a 20% reduction in VE? In other words, the air is a full 20% less dense, and therefore needs the same reduction in fuel. Horsepower goes up, though. I would be forced to assume that this is due to better fuel vaporization and therefore a more efficient burn (causing less ignition lead to be needed and less detonation experienced).
Following this theory, a "normal" valve wouldn't have as much of a fuel vaporization advantage as the ST valves due to the reduction in surface area (the ST valves can "catch" the fuel better, allowing the fuel to absorb more heat and less being lost into the air itself).
Taking this a step further, a "normal" valve with a thermal barrier would have the advantage of not heating the air, much like the ST valve would be shielded from the air by the fuel. However, the ST valve should vaporize the fuel and therefore hold an advantage.
Waddaya think???
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