I used to run it in a '95 Eagle Talon TSi turbo car as an octane booster. You need to add some Marvel Mystery Oil for lubrication and to keep it from eating seals.
Here is the "recipe":
3 gallons of 93 octane
+ 1 gallon of Toluene or Xylene
+ 1 oz. of Marvel's Mystery Oil (prevents cylinder wall wash down)
= 4 gallons of 100 octane unleaded gas
Here's another mixture that I found:
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.