Pinhead, I don't have experience with the grooved valves so I'm just stating my
gut feel. Formation of the flow cone around the valve is critical for cylinder
filling . It appears that his type of modification would have a impact on flow
in this critical area. To me it looks like it would add turbulence and hurt flow, I
could be wrong.
Here's another example claiming enhanced mixture motion at the valve that
enhance flow. May be something there?
"These dimples create a turbulent boundary layer that actually speeds up the
flow by adding energy to it via eddy currents. "
