i been running 93 octane with ethanol in it and i found some 94.5 octane ethanol free. im pretty sure the octane difference won't hurt but im wondering will the ethanol free gas help performance at the track? i assume it will since i lost about 2mpg on the interstate with the ethanol gas.

thanks
dicky

 

Non-ethanol should be an improvement over ethanol. Ethanol's biggest advantage is it's tolerance to KR but less energy per gallon (lower mileage). 94.5 non-ethanol would be my choice and mileage will come back.

If you are stock though, the 94.5 is kind of overkill but good piece of mind.

If you have scanning software, efilive or HPT, you can always check for KR just to be safe

 

sorry forgot to add my car is an LS2 A6 with almost all the bolt-ons and tuned on 93 octane. the only reason i was going to get 94.5 octane is because everything else they have is less than the 93 my car is tuned for.

dicky

 

should be fine if you haven't started messing with the stock tune. I just ran into this same issue but was changing the stock tune. about a 4% difference in AFR between ethanol and non ethanol (ethanol being leaner than straight gas)

http://www.hptuners.com/forum/showthread.php?t=26500

 

I don't put ethanol in my car.

 

some of us don't have that option...it's been in my state for years and every gas station has it

 

yea living in northwest louisiana i dont have a choice either, the only reason i was askin is because im in nebraska working and found some so i guess i load up before i head back home.

dicky

 

Fuel changes dont make gains unless you tune to take advantage of the fuel. It allows more timing and a leaner burn. Ethanol in the 93 has a lower stoic than 93 without it. Running 94.5 would allow about 3 more degrees....10+rwhp.

 

yea i wasn't really worried about the gain of the 1.5 oct difference because im not retuning the car for that since its not something i can get every time i fill up (just getting 94.5 oct since its the only one close to 93 without going below). i was just wondering if the non ethanol gas would have any performance gain over the ethanol gas with out any tuning (assuming its the same octane)?

dicky

 

As much as I hate to say it, ethanol is better for track performance, if you tune for it. Ethanol, ethyl alcohol, moonshine, or corn squeezins' (yep, exact same stuff that comes in mason jars) has an octane rating of 116. The bad thing is ethanol lives to find hydrogen atoms. Because of this it will readily absorb water, either from the air or from the container it is in. This is why it does not travel down pipelines and is only added to fuel at the last minute to the truck that takes it to the final retailer. Here, some of it absorbs water and falls to the bottom of the tank. If you've ever gotten "bad gas" you probably got it just before the truck was scheduled to arrive.

The other bad thing about it is it produces about 40% less energy than gas does. That is why there is a big fall in mileage. E85 will get about 30-35% less fuel mileage than pure gas. One thing a lot of people don't think about is adding ethanol raises the octane of regular fuel, so say you go to the local 7Eleven to buy some midgrade 89 octane fuel. What you are actually buying is plain ole' 87 octane with 10% ethanol in it to bring it up to 89....and you are paying 10-11 cents a gallon more for it. Same thing for 92 octane, it is just 89 octane with 10% ethanol.

The one question I have is, if the government will allow us to make our own biodiesel at home, why won't they allow us to make our own ethanol?

Peach methanol is pretty good, but the Mango ethanol in my downstairs refrigerator is my favorite.