The way I read the chart on the back of the bottle, the one I posted, it shows that it takes 48 oz. with 20 gallons of 93 octane fuel to reach 103 octane. That's 2.4 oz. a gallon. With 12 gallons that would be 28.8 ozs. To take into account the residual gas in the tank, I thought the full 32 would be good. I did this to push the lead as hard as I thought relevent to see if it really could produce the performance levels I was getting with the 99 octane fuel. Without taking it to this level, I don't think I would be confident in saying that the lead just doesn't reproduce the effects of higher octane fuel. Also, I was a little leary of using my engine as a guinea pig and wanted to be sure there wasn't any hidden detonations and at the same time, get a good buildup of lead in my combustion chambers.