On the Kona side on the Big Island of Hawaii my only options for gas are;

92 Octane with 10% Ethanol or 89 Octane Ethanol Free
Which of these is better to use?

Thanks
Steve
2002 Land Rover Discovery II SE

 

In your case get the 89, you will get better MPG.

 

Really Spike? I have that option as well down here

 

Thats what I'd do.
Do this guys, get a MPG app for your phone, for 5 tanks of fuel use the ethanol mix, then for another 5 tanks use the non ethanol mix and see what your MPG is and then use whichever gets you the best MPG.
I dont have a choice here, but I have found I get better MPG based on the brand of fuel, I've been buying my fuel at Costco for the last year, better MPG than Shell even.
I get the best MPG with Mobil but Costco is more convenient.

 

Use the 92 octane, it will give you better MPH simply because Ethanol gives a little more power but goes not give better mileage.

 

Won't the lower octane fuel be countered by the ECU retarding the timing?

Or is that less noticeable on the 4.0l engine?

I once found 91 octane premium with no ethanol and my truck LOVED that fuel.

I normally use the 92 with 10% E because thats all you can get here... and I make sure to use a top shelf brand plus use injector cleaner before every oil change.

I previously had a bad experience using 92 octane premium ARCO brand gas, gummed up the injectors really good.

 

I've been using the 92 Octane w/10% Ethanol from Costco for the last 1.5 years and I've been getting about 13.3mpg, although it has been feeling sluggish going up the steep hills here.
I filled up with 89 Octane E Free at Tesoro this weekend and used a bottle of Cheveron Injector Cleaner. I'll let you know how the MPG is in a week or so.

 

Damn, more MPH I could use some of that!

 

Ethanol does not give more power, 92 octane is 92 octane no matter what the mix with ethanol is.
And it is a well known and established fact that ethanol reduces MPG in everything, especially cars that were built before the E-10 was readily used.

 

Yes and no, Ethanol has less BTU (power) than gasoline so you use more of it, the ECU has to retard the timing anyway because of the less power in the E-10 mix.
Using a slightly lower octane non-ethanol fuel should not retard the timing any more than the E-10 mix.
Thats why I said to track your MPG and see what happens.
But you have to track it over a longer period of time to compensate for your driving different because you know you are using a different fuel blend as well as to give the ECU time to re-map for the different fuel blend.
Just try it guys, your truck wont explode when doing this.
Track your MPG with the different fuels and then post your results.