Jim All my training has been that the reason that the Petroleum Companies began putting alcohol in fuel was to "spike" it to raise the octane to replace the lead. Then the EPA decided that they wanted more oxygen in the fuel to assist in clean burning, so the percentage of alcohol went up in fuels. It was at this point that we as mechanics started seeing alot of carbs, and early fuel injection systems begin to fail at higher mileages due to damage from the alcohol, although it was not blamed on that. Contrary to one netters opinion, alcohol burns longer than regular gasoline, and produces more BTU's, and ultimately more horsepower. That is why alcohol dragsters are a HIGHER class of racing then 100 octane racers are; they are faster. It is also relatively clean burning. The problems: alcohol is very corrosive, and acidic. It eats virtually anything rubber, and damages alot of other stuff not made to resist it. Summitt Racing has a line of carbs made by Holley just for running alcohol. BUT, if the content of alcohol is down in percentage to what it is in most fuels (non-gasohol), then it should take a long time for any damage to occur. The biggest problem with running auto fuel with any alcohol in it in a plane is the fact that the alcohol absorbs water, which is a bad thing! Periodic use of an additive that gets rid of water will eliminate this problem, and is probably only needed if your plane is parked alot. Also, if your vent is to the bottom of the plane making it harder for moisture to enter the tank would be better.
The reason that your mileage dropped with gasohol vs. regular gasoline is that the gasohol burns with more end result of oxygen, so the oxygen sensor was seeing more oxygen in the exhaust, and enrichened the fuel by program to compensate, hence more fuel burn. The program is not set up to compensate for the different fuel type. It probably also is not programmed to be able to advance the timing further and take advantage of the greater resistance to detonation which would also improve performance... Colin Rainey First National Mortgage Sources Lending Solutions in All 50 States brokerpilot9...@earthlink.net
