I burn ethanol when I have to, like on a cross country. I can't tell any difference when I do. I have yet to run any in the winter.

I have had a seeping fuel tank fitting for some time, nothing I do seems to solve the problem, even an entire new fitting. As I have brand new larger tanks ready to install when I get the time (and the weather is lousy) I have put up with it. BUT, I noticed that running some E-10 from time to time made the seep go away. I don't know if that is good or bad...It must swell something up just a bit.

lesuther, I'm not sure you are right about ethanol and vapor pressure problems. I'm rereading the AGE-85 article from August 2000. Ethanol by itself has a VP of ~2 and AvGas needs to be 7. That is why they add pentane to the mix of AGE85 to increase the pressure. I agree that E10 needs the 1 lb. waiver since at that % blend the ethanol does raise the VP of the base gasoline but I talked to Steve Vander Griend that has done a lot of testing and he told me that once you go past 50 or 60% ethanol the VP actually goes down from the base gasoline. Another thing the article says is that fluorosilicone-based seals and nitrile rubber bladders are the materials of choice. Most Cessna bladders made today are nitrile. Also tests showed that AGE85 caused less corrosion than avgas with aluminum.

I believe EAA & Peterson have both done testing with the idea of adding E10 to their mogas STC. Apparently it's a no-go. I don't need to know all the reasons why, just that I shouldn't use it.
There's hope yet-- it seems like more stations are offering E-zero gasoline again. One local station in particular where I gassed up for years until about 2 years ago when they went E10, just went E-zero again about a month ago. Been filling my car up there as well as my airplane-gas cans, since it's only about 20 cents more per gallon than the local E10 instead of 75 cents like my other source. That 20 cents is about a 5% premium, and since my car's gas mileage seems to have gone up closer to 10% it's well worth it.

Decided to check -with ethanol in fuel you WILL get water in fuel -i.e. carb ice in 182 http://www.youtube.com/watch?v=YeCyFxoWPpo Not good

I have been running various levels of ethanol in my Vans RV8 for 2 1/2 years, anywhere from 100% 100LL to 70% E98 and 30% 100LL. The only modifications to my IO 360 superior kit motor is a larger jet in the bendix servo, set up by Airflow Performance.

The fuel flow increases slightly with the ethanol content, about 1.5 gph over 100LL at cruise power.