I've experimented around between Ethanol(E10) and pure gas, 87, 89 and 91 octane...And not just in my V6 Terrain..
I've come to a conclusion that E10 is crap for mileage and power gains..It will work, as modern engines with their ECM's will compensate a little for the lower BTU content of alcohol..But there is a limit to what they can do.
I found for winter months, where it is 40 to 0 degrees F, or lower ambient outside..that 87 octane is perfect....In summer months/temps the 89 octane is perfect for our Terrains..any Higher octane will render no performance gains, so is a waste of money.
I use top tier (Conoco, Shell, etc) Pure gasoline.
Last edited by DPK; 07-21-2016 at 01:09 PM.