[leemj84]

So I live out in Iowa, and it's really hard, if not impossible, to find 93 octane gas. I finally found one gas station, but there's a catch...

The price is the same as 91 octane, and the 91 oct is ethanol free, and 93 octane has ethanol.

What do you recommend? 91 octane without ethanol or 93 octane with ethanol?

[Wolfus Aurelius]

Originally Posted by leemj84

So I live out in Iowa, and it's really hard, if not impossible, to find 93 octane gas. I finally found one gas station, but there's a catch...

The price is the same as 91 octane, and the 91 oct is ethanol free, and 93 octane has ethanol.

What do you recommend? 91 octane without ethanol or 93 octane with ethanol?

My 328i says that 91 is the recommended minimum octane. If that's true of your 340i also, then 93 is not necessary to get the performance you've paid for out of the car. Ethanol-free 91 (and I'm surprised to hear you have it in a corn-growing state) will probably give you better fuel mileage than the ethanol-laced stuff.

If they're the same price, of course, as far your wallet goes it doesn't matter.

[Mr Podman]

91, no corn.




podman

[SteveinArizona]

91. Out here, in the west, 91 is all we get (unless one buys racing fuel). Most current BMW vehicles require 89 but recommend 91.

[BeerHerder]

91. Not sure where in Iowa you are, but I know the Costco in Bettendorf/Davenport has 93 top tier.

[Brett530]

Unless you have a tune, then 91 is fine. 93 would be a waste of money. As a side note, the 93 probably has the higher octane rating just because it has Ethanol in it. Ethanol has lower energy content so you might see a slight decrease in MPG on 93.