I am trying to get some clarification and opinions about octane ratings on fuel. I have a 2000 F-150 with a 5.4L. The owner manuel advises to run only 87 octane gas. I live in SD where the ethenol push is real heavy. Most places sale 85 octance, 87 octane(10% ethanol) and 91 octane gas.

My question is, do they blend ethanol into 91 octane gas reducing it to 87 octane, or does the ethanol even have an effect on the octane rating.

I finally found a Phillips station that sales 87 octane gas without ethanol. Would it be better to run this fuel rather than 87 octane with ethanol. There's only a 2cent difference between the two

 

If there is only a 2 cent difference I would run the straight 87. You can always test a tank of 87 with 10% ethanol and see how the motor runs. If it knocks, add an octane booster and then you know never to use that gas. That is how some do it.

 

Ethanol is cheaper, but doesnt get as good of gas mileage. You will save a little bit using it though. You will just be filling up more often.


I personally dont like putting Ethonal in my pick-up. Ethonal is an alcohol and it atracts moisture.

If you burn through a tank of gas in 1 or 2 days, then by all means go for it.

If it takes you a couple weeks to burn through it, I would avoid it.

 

i've been using the ethanol blend gas (89 octane) in my 3 vehicles for a long time now and have never had a problem with it. here in iowa the ethanol blend is $.10 cheaper than regular(87 octane) and $.20 cheaper than premium(91 octane). i'm not sure about any mpg gains or losses as i have not tracked how many miles i can get out of a tank of regular