TheOtherDave™

And why start a second thread on the same subject?
I'm merging this to your first thread, to eliminate confusion.

UPDATE: The two threads are now merged.
In the future, please keep the discussion of one problem limited to one thread.

mdb20

My bad Dave. I was wanting to post the comments on the first thread, but ended up starting a new thread by accident the other day.

MonteC

Ethanol. There has been a recent trend to make our fuel 10% ethanol by volume. Ethanol has less engergy than gas. Giving you less gas mileage.

Khazzy

woooohoooo im not an idiot afterall, i knew it had to deal with our crappy gas we now have.

mdb20

I know I'm getting into serious nerd territory here, but oh well...I've used E10 and it's readily available here in the Midwest since we grow most of the corn used to make it. There's an ethanol plant in Garnett, Kansas that I've been by before many times while driving. E10 is a little cheaper here, since the crops and the Ethanol plant are both relatively close. E85 is quite a bit cheaper, but has its drawbacks and can only be run in vehicles capable of using the fuel (Teg is not one).

Anyway, E10 typically has an octane rating of 2-3 points higher than regular straight gasoline. So the octane rating is typically 89, the same as our mid grade unleaded. We typically have 87,89 and 91 or 92 octane regular gas and (89 octane) E10 and (105 octane) E85. The E85 usually has a decrease in fuel economy by 20-30% due to less BTU potential in the fuel. Using some "fuzzy math" E10 has around 12% of the ethanol content of E85. This means that it would have approximately a 2.35-3.5% decrease in fuel economy in relation to regular 87 octane unleaded.

This calculates to 7-10.5 miles less, if driving 300 miles on a tank, or 293-289.5 miles instead of 300. These numbers are hardly anything to even complain about. With the increased octane and decreased price, I've even got better miles per gallon and cost per mile on E10 in comparison to regular 87 octane unleaded. So I don't agree that E10 alone is contributing to decreased fuel economy. Gas that's sold in the Winter, has been know to cause reduced fuel economy though, due to percentages of chemicals and additives allowing cars to run easier and smoother in colder temps. It's not Winter yet so who knows?

Fuse

You can run e85 on your car. You will need to tune for it usually you have to add 20-30% to the fuel maps. So you get less gas mileage.

Do some research on stoichiometric.
For gas its 14.7 to one
For e85 its 9.7 to one

Lambda are both 1.0 so if you run e85 without a tune the ecu would probably add fuel to compensate for the lambda value. But you get a code if there is more than 30% correction ether way. This puts the ecu into limp home mode you get shitty ignition timing with this and it all raps up to bad gas mileage.

If you really want to get crazy mpg you can tune gas lean or e85 lean. The only thing is you will not pass emissions for NOX due to high cylinder temps.

As far a octane rating the higher the number the more stable the fuel. Has very little to do with mpg. With 105 octane you can be more aggressive with ignition timing and boost.

You will get the same mpg for 89-91 ruffly because the o2 sensor holds the air fuel ratio around 14.7 at cruise to help with emissions.

Fuse

I think what you are looking for is this. http://ecomodder.com/ have fun. These people are crazy about mpgs.

Khazzy

your integra can run off of e10? wtf? i thought that was for special cars that are made to run off of that gasoline. i take to heart what my gauges say...UNLEADED FUEL ONLY catches my attention haha, if you can, wow awesome, but ill stick with the old school stuff

TheOtherDave™

You're confusing E10 with E85.

E10 is commonplace all over California.
It's a 90% gasoline / 10% ethanol mix; every since MTBE was found to be a major pollutant, ethanol has been used in it's place to oxygenate our fuel and cut down on NoX emissions.

Don't get excited...E10 is not a miracle fuel by any measure. Ethanol contains less energy by volume than gasoline; because of E10's reduced energy, our gas mileage is about 5% lower than on straight gasoline.

What you're thinking of is E85.
That's an 85% ethanol mix. In that case, you're absolutely right.
The GM FlexFuel cars have various sensors and different ECU tunes to adjust the fuel injectors to match the ratio of gasoline and ethanol being used.

Obviously, the Integra lacks these sensors and ECU tuning.
It cannot run E85 from the factory.

If you try to run E85 on a car that is tuned for E10 or pure gasoline, permanent engine damage can result. On a gasoline tune, the ECU won't deliver enough E85 to run safely. The car will run lean and detonation will cause serious engine damage.

Spec R

so if we run straight gasoline dave, will we get the e-mpg numbers in the 40's that are so commonplace on the net (sarcastic, but serious at the same time)? since both our dc4's get relatively the same mpg numbers, a 5% increase would get us what, 27mpg instead of 25mpg?

i didnt know any of this. its good info.