I know most of us has tried at one point or another. I honestly thought it made a difference. Never really had any actual facts to back it up. Just bought based on the brand names. What I found out about them from this video suprised me.....
I'm not surprised that the octane boosters reduced HP. After all, higher octane means slower burning fuel, and the octane booster itself has few BTUs/gal than gasoline. For those additives to work, your engine must require higher octane. If the fuel has the correct octane rating for the engine, adding octane is counterproductive.
Some fuel additives are beneficial. Chevron Techron is a safe, effective detergent. If you live in California you probably don't need it, but if you live in some other state it can make a difference in performance over time. (If you live outside CA make sure your gasoline is Top Tier rated.
This is interesting information Jay, I dont live anywhere near Califorina as I am up in Canada. Still will do some reasearch on what you mentioned. miledge and performance are always somthing I am looking to boost a little.