Originally Posted by Dan

I'm testing some techniques on non-hybrids and something I started thinking of is RPMi (revolutions/mi). Helps me remember that low RPM in a low gear can be less FE than higher RPM in a high gear. The trick is to get where your going with the fewest cylinders firings.

RPMi = 60*RPM/MPH . . . . . . . .// To make the math simple just leave off the 60, that gives revolutions per KiloInch (RPKi).

...simple. Lower the RPMi the better... and neutral has great RPMi as long as your MPH is still high. As for the div0 problem, use limits. As MPH approaches zero, RPMi approaches infinity. Basically translate to "dead stop idling is bad"