This is a great thread! There is a book I've read Forced induction Performance tuning By A. Graham Bell. While it does have lots of info on super/turbo chargers and some normal aspiration, the book's chapter 12 deals entirely w/ fuels. There is no way for me to sumarise the info. into a post so I wont even try, but it is definetly worth a look as there is more involved than I ever imagined. <img src="/forums/images/graemlins/scared.gif" alt="" /> As for the Yota guy posting in the Jeep forum, I'm actualy a Jeep guy as I have an 83 Scrambler in pieces tucked away in my barn. I just pound pavement W/Toys. One day I'll finish the Jeep and all will be right again! Hope the book can help! <img src="/forums/images/graemlins/cheers.gif" alt="" />