Fabrik8

I'm not a big believer that it helps modern central plug, multi-valve combustion chambers that are already designed for good flame propagation and other things. Plug indexing makes much more sense with engines that have the plug on the side of the chamber, like a lot of V8s and V6s. It's just one of many concepts that doesn't make sense to apply across the board to all types of engines, because it doesn't have the same effects on all types of engines. Even with central plug, pentroof designs, different engine designs will respond differently, so one Honda engine design may have no gain and another Honda engine design may have a gain. I'm not really a believer in wasting time doing something unless I know it will have an effect, and if it doesn't have an effect I'll never waste time doing it again.

People often fall into the trap of assuming that something which works well for one thing must work well for something very different.