Here are a few posts I thought were quite interesting:
http://www.keelynet.com/interact/archive/00000804.htm
http://www.keelynet.com/interact/archive/00000806.htm
The second, if you look at the replies, there are many. Pretty much each one has some interesting/useful information. Some good links provided as well.
I like all the references to water injection with electrolysis
If anyone else has any good ones, please provide them
Chris