Jvette73

A 1/3 mix is the max that is recomended. 2 gallons of gas to one gallon of xylene. If you use 93 octane gas and the xylene is 117 octane it works out to a final octane of 101. Also it is recommended to add some type of lubricant like Marvel mystery oil. 1 ounce of oil per gallon of xylene. So two gallons of gas= $3.00 and a gallon of xylene is $5.50 for a total of $8.50 for 3 gallons of 101 octane. Sunoco GT unleaded (100 octane) is $3.50 per gallon which is $10.50 for 3 gallons. That makes the home brew cheaper aswell as being higher in octane by one point.

Chuck Harmon

Not all Xylene is created equal. According to a book I have, highly recommended by the way, Jeff Hartman's "High-Performance Automotive Fuels & Fluids", there are 3 forms: p-Xylene is 116 research octane, m-Xylene is 118 research octane, and o-Xylene is only 100 research octane.

There are sometimes limits to increases of octane if the pump gas already has close to the limit of that particular ingredient. Taken to an extreme, I don't think the car would run very well if fueled 100% with m-Xylene at 118 octane. There is more to gas than anti knock qualities.

Now that gas prices have stabilized, I think it may be safer (for the car), cheaper, and easier to just buy high octane race gas in a reasonable bulk quantity and add a few gallons to each tankfull. It is a shame that there isn't more of a market to justify 95+ octane at pumps across the country.

Chuck