93 octane and ethanol
 

I often buy gas at Costco and noticed last summer that it suddenly had 10% ethanol. It seems to me that any ethanol in gas reduces the "heat" of the gas and that if the price per gallon is the same as 93 octane with no ethanol it isn't such a good deal. I don't think I can tell the difference in acceleration or mileage in my allroad but is there a significant difference?

all gas is 10% ethanol after the summer months. MPG does go down a tad.

True story: I live in Mass and all our gas is 10% ethanol year round. on average
 

I get about 20.5 mpg in a mix of city and highway (but mostly highway). Yesterday I filled out of state from a station without ethanol. I just refilled my tank and averaged 23.1 MPG on this tank of gas (mostly highway)

so 10% ethanol reduced mileage by 2.6mpg (a little more than 10%) . Funny the fuel with ethanol isn't cheaper, and doesn't help mileage

And I bet, with today's contant tune ECU's, the pollution is worse.
 

just a thought.

10% ethanol cuts my mileage just over 10% on the highway.
 

Ethanol does not have the energy content of an equal volume of gasoline. Unless it is priced 10% less per gallon than gas, you are losing. I assume US pumps have to note whether they dispense ethanol, if not, they should. I just avoid it here in Western Canada.

Depends where you live...it's cheaper in Iowa.

Re: 10% year round in MN by law
 

There are exceptions for premium at some stations for off-road, collectors etc...I use it when storing the Boxster for the winter. The newer engines are not affected much by 10% they will adjust. I have done many tests and maybe at most 5% difference. E85 will lower by 25% or more, just ask the people who try it. Winter fuel mixtures in colder climates will lower the mpg more than 10% ethanol. As I have been told in the past the reason for 10% ethanol is to lower polution on cold start prior to the vehicle warming up. Once the polution control systems are warm 10% ethanol doesn't do much.

Unfortunately, around here it's 10% alcohol at most stations.
 

There's only Chevron (I think) and Sinclair that don't have ethanol (yet).

My concern is, what damage will ethanol do to the oxygen sensors, cat, upper cylinder area, and other engine components?

Re: all gas is 10% ethanol after the summer months. MPG does go down a tad.
 

I track my mileage on my Allroad but, have not noticed a difference between winter and summer gas yet.

When I had my older BMW 528i and late model Ford Explorer they both saw a loss of 2 to 3 mpg with the ethanol mix.

Re: Not an issue with 10%, vehicle is designed for it
 

Gets to be an issue if you store the vehicle for a longer term as the fuel with varnish quicker. Best to add stablizer to it.