Acetone! I tried it out in the middle of summer, and for the first time ever had my coolant boil over, I decided I liked my head gasket and opted for a tow. I also saw a personal best RT of ~36mpg out of that car during the same time. I speculated that my engine was running leaner, but I wasn't sure. Then I saw a post about how acetone doesn't do anything special in the combustion chamber, but depending on your oxygen sensor catalyst, can make the ECU think you're running *richer than you are, with the result being a lean running condition. Of course this is all anecdotal, YMMV.
*I think it works by stealing atomic oxygen after the catalyst has split it, which reduces the current and the ECU thinks there's too much fuel and leans it out. Of course I'm no chemist, so who knows?
zpiloto 
Hybrid Mode
