[Jaak]

Here Shell has 91 octane as a 100% gasoline with no eyhanol mixed in. All my gas powered toys run best on this. The Boxster gets better milage as well as being peppyer on the Shell. My outboard engines run the best on Shell 91 as well as my lawnmower, snowblower and chainsaws. If I use any other gasoline mix there is a noticable difference in performance, especially outboard engines. Ethanol has a tendancy of absorbing water which makes it worse with a shorter storage life.

In studies I have seen, ethanol has about 85% of the BTU's that gasoline has resulting in about 10% less power. In my milage records I have noticed a drop in milage when ethanol mixed fuels are used. A Porsche driver here has had issues with his cats burning out when he used Sunoco 94, which has 10% ethanol mixed in it. He has since switched to Shell 91 and no longer has Cat issues.

A few folks I know also have issues with their snowmobile engines failing due to ethanol. The carbs need to be adjusted to a richer mixture as not to burn out the engines. They are in New Hampsire and all they have is the ethanol mixed gasoline.