this does not show actual test results but here it is anyhow from sealed power
Quote:
Notice: Most of the second ring gap recommendations are larger than the top rings. Recent testing has proven that a larger second gap increases the top ring's ability to seal combustion. This larger "escape" path prevents inter-ring pressure from building up and lifting the top ring off the piston allowing combustion to get by. Many engine builders have reported lower blow-by and horsepower gains at the upper RPM ranges with wider second ring gaps. Also, almost every new car made is using this inter-ring pressure reduction method to lower blow-by and emissions and to increase engine output.
