The US OEMs have tested alcohol fuels for a loooong time and up to 10% ethanol is fine. In fact, because ethanol contains oxygen it is more prone to decompostion and forming deposits, so evaluations of detergents in gasoline must use ethanol-containing gasoline to make the test more severe.
No problem with 10% ethanol, Chrysler tests this fuel mix and says in the owners manual that it is fine for these cars. In actual testing, we have found that the engines run slightly cooler internally due to the alcohol providing additional cooling in the intake tract, also the lower energy content of the alcohol will result in about a 1-3% reduction in power when measured on a dyno when compared to 100% gasoline. This also translates into slightly reduced mileage. Here in Illinois, ethanol laced fuel is all we can get, and my Vipers have run fine with it for over 8 years.
While it should reduce volumetric fuel efficiency (miles per gallon) it should not affect power. The fuel enrichment should more than compensate and still provide full power. To what did you attribute the power loss to?
When the tanker came into Costos last week I asked him if there was ethanol in the 93 octane and how much was in there. He said there is the full 10 percent ethanol in the mixture of the 93 octane. I'm getting about 185 miles to a tank full where last year I was getting 200 miles. It's definitely affecting the fuel mileage.
Ethanol is about 1/3 oxygen. If used at 10%, then 3.33% of the gallon is oxygen. You fuel economy should not get worse by more than 3.33%, or a travel distance of 193 miles.
Just a side note-- I put in race gas and the car runs a LOT better, wish I could afford 7 bucks a gallon all the time!!
Race gas is typically higher octane and unless you have higher compression, change the timing, or boost the engine, you wouldn't notice a difference. To get higher octane the fuel usually is made of larger molecular weight materials, so the volatility is poorer (remember that Ford advised people
not to use premium if they had driveability problems.) It might behave worse more often than better. Another way to claim "race gas" is large amounts of alcohols or ethers (see discussion above.) Lastly, higher octane is achieved by tetraethyl lead (say goodbye to your catalytic converter) or MMT (technically illegal in the US.) Neither should affect performance unless your engine knocked beforehand.
There you go, I just slammed a couple of you guys. Sorry, but ask questions to discuss it more.