A partial explanation about octane that might help (people like me). From this site: Northwest Iowa Community College (NWICC) Sheldon, Iowa "Ethanol - As A Fuel" (Modules) http://www.nwicc.cc.ia.us/etsp.htm Note: linked to Keith's site www.nwicc.cc.ia.us/contacts.htm
Excerpts: "Antiknock Index (AKI): Measures the ability of a gasoline to resist engine knock/ping. AKI is the average of Research and Motor Octane or (R+M)/2. Commonly referred to as pump octane." http://www.nwicc.cc.ia.us/glossary.htm "THE AUTOMOTIVE TECHNICIAN The quality of fuel used in any motor vehicle engine is very important to its long life and proper operation. If the fuel is not right for the air temperature or if fuel changes to a vapor incorrectly, driveability will suffer. Gasoline is a complex mixture of approximately 300 various ingredients, mainly hydrocarbons, refined from crude petroleum oil for use as fuel in engines. Refiners must meet gasoline standards set by the American Society for Testing and Materials (ASTM), the Environmental Protection Agency (EPA), some state requirements, and their own company standards. Gasolines are most commonly rated based on their Antiknock Index (AKI), a measure of octane quality. The AKI is a measure of a fuel's ability to resist engine knock (ping). The AKI of a motor fuel is the average of the research octane number and the motor octane number (R + M)/2. This is also the number displayed on the octane decal posted on a gasoline pump. In general, a low research octane could cause a low to medium speed knock and run-on or dieseling after the engine is shut off. A low motor octane could cause engine knock when power is needed during acceleration such as passing or climbing hills. A typical average octane number of 87 would contain a research octane of 92 and a motor octane of 82. However, it could also be the average of 94 and 80 depending on the availability of blending products on hand at the refinery. These different blends can affect engines differently, depending on the octane requirement of that particular engine, and explains why engines can perform differently with a change of fuel. Factors affecting the octane number requirement include:" <snip> "Using a higher octane or AKI fuel will not increase gas mileage unless the engine is knocking or pinging with the lower octane fuel." http://www.nwicc.cc.ia.us/Module5.htm ------------------------ Yahoo! Groups Sponsor ---------------------~--> Buy Stock for $4 and no minimums. FREE Money 2002. http://us.click.yahoo.com/orkH0C/n97DAA/Ey.GAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
