Ive been doing some research on why ethanol drops mpg in our trucks and realized that the reason is 87 octane with 15% ethanol actually has ignition resistance of 93 octane and a lower burn temp. E85 ethanol burns at a even lower temperature and similar to a octane rating or 105-110 depending on if its mixed with unleaded or premium. So if there is a way to have a sensor in our tank that detects the ethanol ratio changing the ignition timing and injection amount in theory we could get better mileage and better power, but with how low compression our older engines our the benefit might not be as relevant to us as the 3.7/4.7/5.7 engine generation.

 

You're running E15 in a '99?

It's not just the timing or compression ratio. Per volume, ethanol has less BTU's than gasoline. Straight gasoline is about 114,000 btu's. Straight ethanol would be about 76,000 btu's.

Flex fuel vehicles have sensors that compensate but it's an entirely new fuel/ignition system, not a retrofit. Even then, they lose a great deal of MPG.

I moved the thread into "general discussions."

 

I burn what is available here in Tucson. Regular is 87 or 88 octane, in the past month I've run as low as 85 octane (bought out in the toolies of N. Nevada.) I couldn't tell the diff between 85 and 87 on my trip. I generally buy whatever is cheapest.

I have no control over ethanol fuel. There's no non-ethanol gas available here in Tucson. It's part of modern life, nothing we can do about it. On my Dak., I ran a couple of tanks of straight 100% gas (regular 87 octane) and I couldn't see any difference in either power or mileage. (Gas was @ Cenex in Chehalis WA.) And, honestly, I couldn't see that it was worth 7 or 8 cents a gallon more. I decided that if I was going to spend the extra cents per gal., my money would do better to get Chevron with Techron.

I don't run small engines like lawnmowers or chainsaws. My 2 stroke leafe blower seems to never run, no matter what gas I use. My Dakota (and my 08 KLR) seem to do okay with what we can get.

So if I'm a little ignorant about the science, it's because I don't have much of a need to know.

 

And just for perspective. When we ran 112 Race gas ($11.50/gal), we burned about 3/4 gallon per 1/8 mile pass. On 100% methanol ($3.25/gal), we burn 1.5 gallons per 1/8 mile pass and 2.25 gallons for a 1/4 mile pass.

Also, Ethanol/Methanol is an acidic corrosive material. It will eat steel alive. Flex Fuel vehicles have mostly aluminum fuel systems with high strength rubber hoses to handle the acidity.

 

My dads car drinks 1-1.5 gallons to 1/4 mile pass useing 100 octane av gas.

 

thats about right