I'm currently working on tuning for lean burn on my Rx8 with the end goal of 40+ MPG from a stock MPG of around 20. Here is a video on why I believe lean burn will work well on the rotary engine, and how you gain efficiency as you go lean.
Yes I could start with a different engine, but where is the fun in that! I'll post more as I get more data.
I done a few different tests so far and I will be posting video and results as I get it edited. So far I've seen a 20% reduction in indicated fuel consumption in idle, but I have not run the test long enough for solid data, nor is data at idle that meaningful anyway. I will be live tuning in cruise when I can get everything set up and recruit a helper.