E10 Gasoline vs 100% gasoline

It is pretty much an accepted fact that using E85 does not makes financial sense because your fuel economy is so poor, it takes away any benefit you might see at the pump in the terms of miles you can drive per gallon.  However, I'm not sure if E10 makes since over 100% pure gasoline.  As you know, E10 is gasoline blended with up to 10% ethonol.  As of 6/12/2011, the local price here is $3.41 per gallon for E10 and $3.79 for 100% fuel.  It seems like a no-brainer that you should buy the E10 and save the $0.38 per gallon.  However, you should see better fuel economy on 100% fuel.  But, is it good enough to offset the higher price?  Well, before I even see what I actually get, a bit of math indicates I need to see an improvement of 2.7 MPG on 100% gasoline to account for the higher cost.


Here is my experience on the issue.  With E10, in mixed city/hwy driving, I get 24MPG in my 2011 Ford Escape.  With 100% gasoline, I get...

Wait for it....

24MPG...

So, even accounting for 1 or 2 MPG error with my experiment, I'm not getting the 26.7 MPG I need to justify the higher cost.  Looks like I'll stick with my local 7-11's E10.