Using ethanol free gas.

Turtle n Peeps wrote:

JaxDad wrote:

Turtle n Peeps wrote:
E free gas will give you about 4 to 5% difference in mileage.

If anybody tells you appreciably more their math is wrong or their testing is flawed.

E gas will always give you more power because of the O2 and cooling effect it give your engine.

If you only drive your vehicle in a laboratory that MIGHT be true, however in the real world we have to deal with water-entrainment, sensors thrown off by water, phase separation and the further increased inefficiencies after phase separation occurs.

Even the EPA has acknowledged that E10 gasoline can (at 70 deg. F.) hold 50 times the water in solution than E0 gasoline can. At just 0.5% water-entrainment phase separation begins.

Bottom line, you cannot lose just 4% or 5% in mileage when you have nearly that much water in your tank.

Sure you can.

Water has 0 calories in it. If you have 0 calories in water and you have 1/2 percent water in your fuel you will lose 1/2 percent in mileage. The math really is that simple.


Phase separation has never been a problem for me (or anybody else that I can tell). I have never heard any huge talk about it on the forums that I go on. In fact, phase separation is a non issue unless you live in - degree weather and keep your gas in your tank for a VERY long time. A lot of racers use E85 and if it was a problem everybody would know about it.


Bottom line is I'm not a fan of E fuels at all. But they are here to stay whether you or me or anybody else likes them or not. And at 10% they do a great job of cleaning up our air. So that's not a bad deal at all IMHO.

Three Ethanol Myths Clarified.

In order you raised the points. Fuel has BTU's not calories, possibly kilojoules, but definitely NOT calories. But if the water entrainment was 0.5% I probably wouldn't be worried about it but it's more like 5.0% (or a bunch more, see below) on average.

Phase separation does NOT require a particular temperature range or time frame. It is caused by exceeding the point at which the fuel blend (10% Ethanol) can no longer absorb any more water, but the ethanol can still absorb more water and it's available to be absorbed. When that threshold is surpassed the water-laden alcohol drops out of solution with the gasoline. At that point you no longer have 50 gallons of E10 in your tank, you have 45 gallons of E0 gasoline and 5 gallons of straight, albeit water-laden, Ethanol. When that hits your engine, the fertilizer hits the rotary air circulation device.

Speaking of the math being really that simple.....

If you get 20 mpg on straight gasoline (we're talking average everyday vehicles, not the very few RV's percentage-wise) but you lose just 10% (2mpg) of that (the typical real world experience of most people is 15% to 20%) on 90% gasoline / 10% ethanol and you drive 1,000 miles you will use (1,000 miles / 18 mpg) 55.6 gallons of E10, which is 5.5 gallons of ethanol and 50.1 gallons of gasoline.

If however you'd got that original 20 mpg you would have only burned (1,000 miles / 20 mpg) 50 gallons of gasoline.

Except now you've burned 0.1 gallons MORE gasoline PLUS the 5.5 gallons of ethanol.

Can you please explain how burning MORE gas than before PLUS an additional 5.5 gallons of ethanol can possibly help with 'cleaning up our air' any?