zras01

There is a gas station near me that has 92 Octane, ethanol free fuel.

Is there any reason that I cannot or should not use that in my 2008 LS3 C6.

I have been purchasing it for my small engine equipment, chain saws, weed eaters, Kawasaki Mule, etc., and it has been wonderful.

Are any of the Vette engine parts "designed" with the ethanol in mind that might be affected by using non-ethanol fuel.

schpenxel

No issues. Pump gas can be 0% ethanol or 10% ethanol, you'll never know which.. and neither will hurt a thing.

gbrtng

How fortunate - does the station support the farming community? Not much pure gas left anywhere.

zras01

Actually it does! I live near Crockett TX and cattle and timber is what keeps most folks going here. Only one place here has it though and that happens to be a farm and Ranch supply. I

jrose7004

I go out of my way to buy non ethanol fuel for my Corvette.

jesse82nc

I go out of the way to buy high ethanol fuel for my Corvette

Well I guess it's not out of the way when there are 15 E85 stations within 20 minutes of the house lol. $1.35 a gallon too right now!

2k Cobra

What kind of mileage do you get with E 85??

Can you run E 10 in it too??

TIA: 2k

jesse82nc

I can run anything in it, around town and sitting in traffic regularly, on E85 I get around 16 mpg. On the highway I have gotten close to 20 mpg.

Purple92

If I remember correctly - the GM PCM (engine computer) keeps track of both a "short term fuel trim" and a "long term fuel trim". Think of those as a air fuel ratio "tweaks" (I believe it does so for each bank in the V-8 actually). I would expect that the E10 will require a bit of a different long term fuel trim than the non ethanol gas would.

So - while the ethanol free gas certainly won't hurt anything, and would probably be preferable due to the potential for the ethanol stuff to deteriorate faster - the computer may take a little while to learn the fuel trim for the straight gas.

What that means to me - is that I would try not to switch back and forth between the E10 and the straight gas too much, and I would try to run at least a full tank of the straight gas before doing something like a track day, a night at the dragstrip or any event that involves full throttle for SIGNIFICANT amounts of time. I know that the PCM goes into open loop at anything approaching WOT, and completely ignores the Oxygen Sensors, but I really don't know if it incorporates the fuel trim values in open loop.

schpenxel

Difference in fueling from e0 to e10 is about 5%. Fuel trims will soak this up in no time.

Positive long term fuel trims are carried into WOT fueling. Negatives are not

Pretty much all gas is e10 now unless stated otherwise, so I wouldn't worry much about it. Even GM has changed the AFR their cars calculate fueling off of to 14.1 instead of the old 14.7:1 because e10 is so common.

jesse82nc

My Long Term Trims are disabled. Makes it easier to switch between E85 and E10.

schpenxel

It's going to take next to no time to react regardless

0JDP Tech

Actually, there IS something to consider here. While I won't argue that the Ethanol Free fuel is better for your car in theory, there is another thing in play that I have seen a couple of different times. Most recently while tuning a ZL1 for a customer after having installed some goodies for him. We had to pull timing because the car had bad gas. When the customer picked up the car he insisted that he only runs the best fuel available. 91 Octane (thats our high here) Ethanol Free fuel.

The problem with this fuel is that very few people seek it out and as a result, the fuel can sit in the ground for much much longer than the regular premium fuels do. In our experience, TOP TIER premium is your best bet. Ethanol Free sounds nice but around here at least, it has proven not to be the best gas for this high HP machines.

All the best,


Jared Royce
888.308.6007

schpenxel

Riddle me this....

Most agree that E85 is great for high HP applications as it's high octane and very resistant to knock

Most hate on E10 because it has ethanol in it

Those two things contradict each other in my opinion.. either ethanol helps with knock or it doesn't.. can't be both.

I guess the possible answer is 93 octane E10 starts life as say 91 or 92 octane, then they add 10% ethanol to bring the octane rating up to the advertised 93 (while reducing the stoich ratio)

Welcome to the random things that go through my head...

jesse82nc

I've often wondered that as well. E85 I believe starts out as 87 octane and then they add 85% ethanol to it. Pure Ethanol is 99.15 Octane using the (R+M)/2 method typically used. (87 * .15) + (99.15 * .85) = 97.33 Octane. Even if they used 93 to make E85, it would only raise the Octane to 98.23. - https://en.wikipedia.org/wiki/E85#Octane_rating

schpenxel

I always though E85/100 were higher octane than that.. but most things I had read previously were using only one of the values.. not (R+M)/2, so that is why. It appears your numbers are closer to real world numbers with what we're used to calling "octane" in the US.

Someone else PM'd me a while back and said that E85 is pretty much the crappiest gasoline mixed with the dirtiest ethanol they can get away with and that it can be pretty nasty stuff. I was told it isn't regulated as strictly as gasoline. So, that has me shying away from it for the time being.

I'll just keep dumping pure methanol in under boost

jesse82nc

Yes, unfortunately there is a ton of misinformation out there on E85. Many mis quote it to 105 octane. The RON Octane number alone is about 108 Octane. By comparison, typical 92-93 has a RON number of about 97.

On E85 you can typically raise the compression about 1-2:1 above what you can on 93 octane. That would go in line with the fact that it is 97-98 octane at best. I'm no expert on the matter though.

For reference, pure methanol is about the same octane as pure ethanol. It's maybe 1 off at worst.

schpenxel

I'm finding pure methanol is around 99 too.. that should be plenty to help stop knock at least

http://www.saylor.org/site/wp-conten...cohol-Fuel.pdf