Never heard of this one but it interests me.
Here is a interesting link:
I did do the acetone experiment. Did it for 6 months on three different cars too. I concluded that it did make a difference. However motors with electronic fuel injection saw a minimal increase *at best*. They ran no different. The only time I could tell was looknig at the cars on board instant mpg readout. In certian sitations it did show a repeatable increase. But its not enough to go through the trouble of putting in 2-3 oz at every fillup.
Although... a carburated motor will show a supprising increase. My 87 MCSS saw a solid 2.5mpg better average. No joke.. it gained in hot temps and cool temps. Idled noticably smoother too. I had to actually lower the idle speed because everytime I ran it my rpms were 100higher. I went back and forth using/not using it just to prove it to myself. Sure enough.. it does indeed work.
My thoery on it is fuel atomization. A EFI motor does this pretty well by its design. But a carbed motor leaves a lot to be desired when it comes to keeping fuel droplets suspended in the intake charge.
Oh and for what it's worth.. a friend with a 05FX4 ranger tried the acetone thing for about 5-6 tanks and saw no increase.