Most gas around here has 10% ethanol. I understand that this causes a reduction in gas mileage (I've read 5%). Does ethanol also cause a loss in performance (horsepower) since I believe it has less energy per gallon than regular gas?

 

I've been wondering that too, but never looked into it.

I just did a search and found this page: http://www.ethanolrfa.org/factfic_enperf.html
which says:
"Ethanol is a high quality, high-octane fuel capable of reducing air pollution and improving automobile performance. Because ethanol is the highest-octane fuel on the market, it helps your car run more smoothly. It also keeps your fuel system clean for optimal performance because ethanol won't leave gummy deposits. And because ethanol burns cleaner, it produces fewer emissions. Today, all vehicle manufacturers approve the use of up to 10% ethanol blended fuels, and several even recommend ethanol use for its positive environmental impacts."
and
"There are many variables with regard to fuel economy, including the season, the weather, and the state of tune of the vehicle, road grade, tire pressure, and the use of air conditioners. In fact, some carbureted vehicles that run rich experience an increase in fuel economy with ethanol-blended fuels. Other tests and studies suggest that fuel economy may decrease by approximately 2% in fuel-injected cars, such that a car averaging 30 miles per gallon (MPG) on the highway would average 29.4 MPG using an ethanol-blended fuel, not enough to be detected by the average driver. At the same time, the use of ethanol contributes to a cleaner environment, stronger economy, and increased energy security."

:confused: I guess it's okay...

 

I wonder if there would be a dynoable difference or a 1/4 mile difference if two cars were compared side by side, one with 10% ethanol gas and the other with straight 100% gas.

 

It would be great if we could get a dyno comparison of two cars, one with regular gas and one with 10% ethanol to see the difference.

 

I've been living in Iowa for the past 10 years and we've had ethanol the whole time.

Most stations offer 3 octane ratings. 87, 89, and 91 or 92. Only the 89 octane is a 90/10 ethanol mix. In fact it is the cheapest gas available because non-ethanol fuels are taxed more in this state.

If you can find ethanol mix and gasoline in the same rating I bet they would dyno the same.

Eric

 

I believe the owners manual specifically says not to use fuel with ethanol
or methanol. Are they close to the same?

 

Ethanol will actually boost the octane rating to the gas it is being added to i other words the existing fuel with out the ethanol will have less octane.
Ethanol is not good for fuel system parts as it hold moiture and produces moisture and condensation and corrosive properties, that is why some do not suggest long term use of ethanol. :eek:

 

Ethanol does not produce moisture. The problems you refer to is due to the fact that ethanol mixed gasoline does not mix with water, at all. It will seperate. This is the same effect as putting HEET or Isopropyl alcohol in your gas tank (another benefit of ethanol in northern states).

As far as not recommending long term use of ethanol. Every non high performance car I have owned over the past 10 years has used 10% ethanol with no ill effects. Everyone I know uses ethanol gas.

Eric

 

They are not the same, and I believe you are mistaken regarding the owner's manual referencing use of ethanol-blended fuel; I'm pretty sure a 10% mixture is considered OK by GM.

 

The only downside I have heard from ethanol is that it does not have as high a specific energy content as gasoline so you have slightly less power output. (maybe that coresponds to the -2% MPG) I have also heard (no real sense if this is true) that ethanol requires heavy subsidies and actually takes more energy to manufacture than it produces.

 

I checked around a bit more and found that the horsepower should be about the same with 10% ethanol as with straight gas. Basically ethanol has less BTU content than regular gas but it has much more oxygen. This is probably a bit oversimplified but in order to keep the air / fuel ratio correct with a 10% ethanol gas, the modern computerized engine pumps more gas into the engine which causes the reduction in gas mileage but the extra fuel offsets the power loss.


[Modified by fifimonster, 8:49 PM 5/24/2002]

 

I believe this to be true, the argument is that if we consumed more of it, it would be cost effective.

Eric