Serious discussion: Fuel Mileage, ethanol blending

HiTempguy wrote:

Zomby woof wrote: Shell seems to be playing a little game with the ethanol/no ethanol thing. Depending on who and when you ask, they either have it or they don't. They also have claimed to be both ethanol free and top tier at the same time.

AFAIK, regular is up to 10%, silver is up to 5%, and premium is 0%. That's how they get it to average out to meet the 5% federal rule. I know for a fact that their premium is ethanol free though!

I usually use Shell ( discounts from the grocery store apply to Shell) and my Integra gets the same milage on 87 / 91 / 93 ... then suddenly I'll get 5 - 7 more mpg on a particular tankful ... figure they must have had a load without the usual amt of ethanol....

For readers in the PDX area......

http://olsonbroserv.com/alt-fuels.htm - I just called and confirmed... these guys in Portland sell non ethanol premium

14115 Southeast McLoughlin Boulevard (99E) Oak Grove, OR 97267-1406

Now I have to wait till the tank is low and see how she drives, and the mileage I'll get.

I recently drove to Tacoma and back and averaged 31.31mpg for the round trip. I wonder what the mileage will go to... if it even changes

tank was down by a bit more than half, she took 7.01 gals @ a cost of $30.71... or a price per gallon of $4.39

Ethanol has half the specific energy of gasoline, which is to say, one gallon of gasoline has twice as many BTUs of energy as one gallon of ethanol. So 100% ethanol (E100) would yield 50% the mileage, and that's linear. E10 will give a 5% mileage drop, theoretically. In a car with a carb, I think it would run lean, since it can't adjust the mixture, and therefore the mileage drop might be greater than 5%.

What about a turbo car where the reduction in specific energy might be offset by the ability to run more ignition or boost or not enrichen mixture? This probably wouldn't offer any benefit just trundling around town; probably only when the ECU would otherwise be retarding ignition or reducing boost or adding fuel.

But this is just not-fully-informed speculation. This is a good opportunity for GRM to research the facts and set us all straight.

David

I know that E85 is pretty much race gas for every car around here with a blower or a turbo. The reduced energy allows them to crank the timing and the fuel cooling effect allows the boost to go up as well. The mileage suffers due to both the E85 and the Lead foot though

E85 can be a PITA to start in the cold too

I've always figured the mileage hit for E10 to be around 10 to 15% reduced fuel mileage. The net effect of this purely political policy is to allow gasoline retailers to sell more product. It does absolutely nothing to reduce our dependence on foreign oil, and it raises the price of corn and all food product derived from corn. A shining example of govt policy at its misguided worst.

I think something to consider, at least where i live, is the pumps are labeled "May contain up to 10% ethanol"

Key words "May", and "up to". Could 87 sometimes contain only 5%, other times 8%, or 10%, depending on what is delivered to the station? Or does this just cover the theory that mid grade and premium have less ethanol?

I agree that ethanol isnt a solution to our foreign oil dependence. just because it happens to work doesnt mean its the right answer. But hey there is a buck to be made. I dont think there is much more to it than that.

Wow, if it reduces mileage 10-15%, I could get close to 50 mpg with my Fiesta.on straight gasoline.

I read once where some one tested the "up to" percentage and it was 9%. Of course it depends on circumstances.

1988RedT2 wrote: I've always figured the mileage hit for E10 to be around 10 to 15% reduced fuel mileage. The net effect of this purely political policy is to allow gasoline retailers to sell more product. It does absolutely nothing to reduce our dependence on foreign oil, and it raises the price of corn and all food product derived from corn. A shining example of govt policy at its misguided worst.

I guess it had an effect on air pollution in metro areas and the like but you bring up a good point. On modern, correctly running vehicles with cats, is it still a good idea? I would think no. J