Taken from:
http://forums.evolutionm.net/showthread.php?t=269425
Here are some common ways to boost your octane using off the shelf products. I pulled this off another car site.
Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.
Formula #2 - Xylene
R+M/2.........117
Cost...........$2.75/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, ie. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.
Formula #3 - Methyl-tertiary-butyl-ether (MTBE)
R+M/2.........118
Cost...........$3.50/gal
Mixtures with 92 Octane Premium
10%...........94.6 Octane
20%...........97.2 Octane
30%...........99.8 Octane
Notes: Oxygenate. Very common in octane booster products. Has lower BTU ontent than toluene or xylene, but oxygenate effect makes the gasoline burn better and produce more energy.
Formula #4 - Methanol or Ethanol
R+M/2.........101
Cost...........$0.60 - $1.75/gal
Mixtures with 92 Octane Premium
10%...........94.3 Octane (Methanol)
10%...........94.7 Octane (Ethanol)
20%...........Not Recommended
Notes: Methanol is wood alcohol. Ethanol is grain alcohol and found in Gasohol in 10% ratios. Both alcohols are mildly corrosive and will eat gas tank linings, rubber and aluminum if used in excessive ratios. Main ingredient in "Gas Dryers", combine with water.
Formula #5 - Isopropyl Alcohol and Tertiary Butyl Alcohol
R+M/2.........101
Cost...........$0.60-$1.50/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........Not Recommended
30%...........Not Recommended
Notes: Similar to Methanol/Ethanol. Isopropyl Alcohol is simply rubbing alcohol.
Sample Mixture
To make your own octane booster, it is easiest to make up a large batch, and then bottle it up in "dosage-size" uses. Below 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 toluene 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.
~~NOTE:I AM NOT RESPONSIBLE FOR ANY HARM THAT MAY COME FROM WORKING WITH DANGEROUS CHEMICALS OR THE IMPROPER MIXTURE OF SAID CHEMICALS~~
