Here is a formula on making your own octane boost
MAKE YOUR OWN OCTANE BOOSTHow to make your own octane booster (this is the basic formula of one of the popular octane booster products). To make eight 16 ounce bottles (128 oz = 1 gal):
100 oz of toulene for octane boost
25 oz of mineral spirits (cleaning agent)
3 oz of transmission fluid (lubricating agent)
This product is advertised as "octane booster with cleaning agent *and* lubricating agent!". Diesel fuel or kerosene can be substituted for mineral spirits and light turbine oil can be substituted for transmission fluid. Color can be added with petroleum dyes.
Here is a formula for blending fuel also - it is (#oct x gals) + (#oct x gals) / total gals = oct - an example using the (r+m)/2 rating and a ten gallon tank - we will figure the toluene to be 112 octane - (87 oct x 8.5 gals) + (112 oct x 1.5 gals) / 10 gals = 90.75 octane - simple as that!!
I've uses toluene for years as an octane boost - it makes up 15-20% of todays fuel - it use to be a higher percentage than that "back in the day" - 10% won't hurt a thing - personally I prefer to blend oxygenated (with MTBE) race fuel with pump gas - really brings a motor to life!!