Searched to verify my math and assumption. Found the below quote is consistent. You shouldn't notice any difference unless your tune is already very lean.
"Ethyl alcohol contains only 2/3 as much energy per gallon as gasoline hydrocarbons do, so the more alcohol you add to motor gasoline, the leaner your mixture becomes. With E10, the lean-out effect is 1/3 of the 10% ethanol, or 3.3% - easily covered by the safely rich condition of most street-operated carburetion"
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