Non-alcohol gasoline = better FE.
 

If you can find it, get it. Unofficially it can get you roughly 10% better fuel economy. Subject to GREAT argument, of course.

http://i273.photobucket.com/albums/j...Phillips66.jpg

http://i273.photobucket.com/albums/j...hillips662.jpg

Man I wish I knew if this was true.

I recently had my personal best tank but I made a ton more changes so I'm not to sure if it was the non-ethanol fuel or my other changes that gave me a 4.49mpg increase.

Using higher density fuel doesn't really constitute better "FE" (or a "mod"), you are not changing the number of btus used, just the volume. Not a fan of ethanol, just saying.

there are multiple older threads about this...

where do you get 10% difference in fuel economy? if the fuel is 10% alcohol you dont lose 10%, the alcohol still contributes. i believe 10% alcohol fuel has about 3% less BTU, but the idea that it correlates directly to mileage has been debated. some even claim better mileage with 10% alcohol.

10% difference = real world results. Not just my results. I'm pretty sure I mentioned nothing about linearity between the percent of alcohol and fuel mileage gain. Sorry if my first post implied this.

Any time you add methanol or ethanol, you are reducing BTUs even comparing same octane fuels.

I support that 10%....
 

When I use 10% mix gas i get about 10% less mileage...sounds kinda weird but true...just try it.

When road tripping last month I actually got my best mileage running E10. We made no effort to conserve gas and still averaged around 27 the entire trip. With the E10 tanks it was 29 and 28.

*did not read thread*

You should not lose 10% economy with E10. Somewhere around 5% is normal though.

I too notice a 10% drop in fuel economy using ethanol fuel. I believe it's something with the 3800 engine and programming, as other folks with the same engine/transmission combination notice a similar drop in economy when running E10.

Now a more modern car designed/programmed for ethanol in the gas might do better on E10 than my couch.

My dad has an Impala with the 3800. I'll have to get him to run 100% gas in it.