I filled up at Meijer yesterday afternoon. Here are the stats:
Price E85: $3.46 a gallon
Price 87 Octane gas: $3.96 a gallon
Gallons E85: 4.513
Gallons 87 Octane: 10.036
Gallons left from tank #12 (@~37.670%% ethanol): 1.851
I'm assuming that the E85 is 79% ethanol, 100 octane.
Ethanol content of tank #13: 32.12%%
Octane of tank #13: 91.167
32% ethanol is a level that I know the ECU can handle without a CEL. The only question is, will the CEL clear by itself, or do I need to disconnect the battery again? I'm going to just drive it and see if it goes away.
It's a little hard to say exactly because the dealer reset the mileage, but I think that tank 13 finished with a mileage of 24.2. Average speed was 31 mph.
Once again, shortly after I filled up, Meijer dropped the price of E85 by 10 cents a gallon! D'oh! My timing is impeccible.