Two questions about ethanol in gasoline.

So the province I live in is toying with the idea of making all gasoline sold here into ethanol blended. Currently we have the choice, Mohawk / Husky stations sell clearly labeled Gasohol, every other station does not.

These guys over here (Renewable Fuels Assoc.) state that:

While two threads on these boards state the opposite, that since ethanol has less chemical energy by mass in it than gasoline, there’s no possible way you can get the same distance from it.

In my field experiments with my 1992 Honda Civic and 1995 VW Golf, I have confirmed the SD’s statements over the RFA’s. When I calculate the mileage difference between 10% ethanol and non-oxygenated fuel I get on average 25% less distance out of the 10% ethanol, a far cry from the RFA’s 2%. This is over 6 years of tracking my fuel consumption at every tank, in all types of driving and temperatures. Both my cars ran well on the alcoholized gas, easy starting even when it was painfully cold, lots of power, no problems. Fine, so long as I’m reducing the bad emissions more than 25%, gasohol is good, right?

Question 1: Am I? What’s the break-even point when I burn more fuel that releases less emissions? Does 10% ethanol release 25% less emissions or better? I don’t want to involve the costs of producing the ethanol yet, just what comes out of my tailpipe.

Question 2: Is there anything I can do to my car that would allow it to get more distance from 10% ethanol fuel? About the only things I could easily alter are spark plug gap or the thermostat. Everything else, like timing and valve lift is set in stone or controlled by the ECM.

Question 2a: If I had a magical engine that had variable everything, what could I do to get more distance from 10% ethanol? Camshaft change? Compression ratio? Spark timings? Operating temperature?

There’s more to fuel mileage than energy density. It could very well be the case that, although ethanol has a lower energy density than gasoline, the ethanol is burning more completely than the gasoline and is thus releasing more energy.

Put another way:

If I drive 100 kilometres I will burn 10 litres of normal gasoline. This will cost me 6.54$ and will release X quantity of carbon dioxide, hot water, carbon monoxide, carcinogens, toxins, acid rain etc.

If I made the exact same 100km trip with 10% ethanol gasoline in the tank, I will burn 12.5 litres. This will cost me 7.85$ and will release Y quantity of carbon dioxide, hot water, carbon monoxide, carcinogens, toxins, acid rain etc.

With ethanol I burn more fuel doing the same distance. But even though more fuel is consumed, by virtue of the fact that ethanol gasoline is less polluting, is the quantity Y more than 25% less than X?

The reduction in pollution has to be greater than 25% (and significantly so) or else I am throwing money away with no benefit to the environment.

One thing that should be understood about gasahol or gas with MBTE for that matter is that if you are using it you are not only carrying the fuel but also the oxidizer (or some of it at least).

This adds weight and decreases energy, and increases cost as opposed to getting the O2 required for combustion directly from the air.

It does reduce polution as there is more O2 and the O2 is distrubuted more evenly (well it’s O in a chemical bond, and not O2), espically during startup.

If you read between the lines of the quote you posted it could very well read:

Carberated cars are usually run a little rich to make the engine run smother. By using oxygenated fuels you sort of set it to a leaner condition and might have a rougher idle.

Also just to add, don’t use ethanhol in 2 stroke engines as it will eat through the carborators - or at least that’s what my outboard motor manual says. I’ve also heard this problem with snowmobles which is more common since oxygenated fuel is more commenly sold in the winter