Zjoe6

Try it and if you hear knocking or noises jump up to 93. If you live in the southern area of the country the 91 might not cut it on hot summer days. I run only Mobil 93 octane with 10% ethanol in mine. Runs great.

JK 23112

In this area of Virginia, it is all but impossible to find non-ethanol gasoline. I always run 93-octane "top tier" premium gasoline from Valero, Shell or Costco. All of the gasoline sold in our market is E10. The only 'non-ethanol' gasoline I know of is sold at marinas (something about ethanol & boats not mixing well) or way up in the Shenandoah Valley about 100 miles away from here.

From what I have heard, the C7 will do fine on E10 and the proper octane is more crucial than whether or not there is ethanol in the fuel.

mbaessler

JK: You will lose some gas mileage and there is a tendency for alcohol and fuel to separate when stored for awhile. So need a stabilizer. No hit to HP or performance at all.
Like you said have the correct octane is most important.

JK 23112

Yes, I know that E-10 has a slightly lower BTU "energy" content than does straight gasoline - which is why the miles per gallon may suffer a bit. I am aware that ethanol poses problems when stored for long periods of time or during very cold weather (because of its affinity to attract condensation).

As I live in Virginia, we DO indeed get some winter weather down here.....but it never stays super cold or snowy for long periods of time. I have owned my 2017 Stingray a bit over two years now and the longest it ever sat was two weeks. Most of the time, I take it out at least once a week and try to go for a rather long drive with it. I also tend not to let the fuel level get below half a tank. I spoke with a GM tech and he said that a fuel stabilizer wasn't necessary on this car unless I was going to leave it sit for more than a month at a time (as some folks do in the far northern states); so I am hoping all will be okay.

On the plus side, ethanol does help with the octane (and we know that octane is important to the Corvette & other performance vehicles).

FWIW, I wanted to take my car out today - but there is a very slight drizzle right now - so that won't happen. Maybe tomorrow afternoon if I finish work early enough.

mbaessler

Yes no worries on a short time of storage. I have a 2017 also.Love that car! And I'm like you. When I take it out or go on club runs, I like it spotless.

~Stingray

I have a Sunoco near me. None of their pumps have notices of 10% ethanol and they are within a few cents of the marthon down the road that is 10% ethanol. I always fill up at Sunoco. (bonus, they are nascar fuel of choice!).

I have a 14, so I am supposed to be using 91 and not 93?

6spdC6

NO it is much better to use than that ethanol crap (up here its more expensive, big deal its worth it) IMHSHO . I now can get real gas close to home but for about 5 years I had to go 25 miles for good gas. I did my best to always get gas there and for my 2 stroke tools and toys and standby generator and ATV I would bring 6- 5 gallon cans in my PU truck for that gas!

recentlydivorced

Well, live in houston only place to get non ethanol gas is on the water and my vette doesn't float. LOL

AT T 2D

I use top tier 93 octane with ethanol in the cars that I drive regularly without any issues. I find that when the ethanol gas sits for more than a few months, even with Stabil added, I start to have issues. Fortunately I live near a lake and can get 93 octane pure gas nearby. That is what goes in the chain saws, mowers and Kawasaki Mule. I had horrible problems with the mule not wanting to run properly until I figured out it was the ethanol gas. I also have an '89 Turbo Trans Am that is very sensitive due to factory 16.5 psi boost. It gets the non-ethanol as well because the computers in the Buick 3.8 V6 just can't deal with the ethanol fuel after it has been sitting for a month or two. It has a knock gauge and it shows me how much it is retarding the timing trying to adjust.

subieworx

I feel like all the Pro "pure gas" people think this way due to some misguided political belief. There is no physical reason on a performance car to not run an ethanol gas mixture.

PatternDayTrader

Worse mileage is one reason.

WFP

All cars these days are designed to run on ethanol with no detrimental effect where ethanol is added , however like has been stated it degrades over time so a car that is stored over the winter has the potential for problems. I always try to store the car with 100% gas with no ethanol. Small engines on tools are another story. I, on many occasions have I had to go thru the fuel delivery system and clean them up before they would start after having been stored for long periods of time with ethanol fuel. As engines are running they seem to be self cleaning but let them sit for months on end and a varnish builds up. Your experience may be vary.

6spdC6

If you say so it must be right!

Hey guy whatever floats your boat! Its my car (and many other engine equipped things) I have at my house. Over the years I have seen and felt the differences from that ethanol gas mix that was stuffed up our backsides. Taking long trips I have been well able to see the differences in mileage and especially with my Z06 the difference in power!

***I'm specifically talking about that mix in the normal pumps, not talking about E85 thats a separate subject!)****

Add to that I'm a boater and when the only gas available was ethanol crap it was a major difference in power. I lost over 3MPH with my performance boat. Three MPH might not sound like much but its well known in the boating world that it takes about 12-15HP for each mile gained above a speed of fifty.

Why you put in its due to politics I have no clue. I have been a gear head since the early 1960s and thats how I see it. Its well worth it to me to pay more for good gas for my rides, toys and tools!

Rapid Fred

Not so much "supposed to" as 2014 owners' manual says that is the recommendation, meaning presumably 93 buys you nothing.

BUT, newer C7 owners' manuals now recommend 93. Suggests to me Vette engineers figured out that in fact you do get a little HP and/or MPG bonus from the higher octane. IF you have a choice where you live, the odds are 93 is only a couple pennies more expensive than 91, so you cannot hurt yourself, and will probably benefit slightly, from using 93. I have made that decision for my 2015 C7 after over a decade of saving $ by blending 2/3 93 and 1/3 87 (i.e. creating 91) on my C4, C5 and C6 fill-ups...

LDB

I’ll stick with what I said back in post #7, namely that E10 does not give performance problems in a modern car. Supporting that view by lack of saying anything to the contrary, no car or oil company has ever to my knowledge said E10 is a performance or reliability problem for any modern car beyond the roughly 1.5-2% mileage drop for E10. All such statements either concern older cars or other applications not designed for ethanol, or are vague “I notice the difference” statements on the internet. Neither I nor oil companies nor auto companies like ethanol due to its economic silliness and lack of claimed environmental benefits. But that said, there simply is no performance related issue beyond the slight mileage drop.

As far as the boat example, very few boat engines have closed loop control with oxygen sensors. For engines without closed loop control, since E10 contains a bit less energy per gallon (which is what causes the mileage drop), E10 will cause the engine to run lean and lose a bit of power. But with a modern car, the closed loop system will keep the engine at constant air to fuel stoichiometry and there will be no power impact. If a power reduction for E10 is claimed for a car built since the early 1990’s when closed loop control arrived, it must be coming from either imagination or the E10 gas being a lower octane grade which has caused the ECM to pull more timing. Only octane causes timing to be pulled, not presence or absence of ethanol at the E10 level.

N875ED

Ethanol in gasoline, as stated above, does increase octane (and helps the corn farmers with a whole new customer base) albeit with an energy content about 2% less/gallon. The bad thing about gasohol, as it used to be called, is that it is hygroscopic...it loves to absorb atmospheric moisture. In a modern fuel injected auto engine, that has a sealed fuel system, it takes a while to absorb enough moisture to have a negative effect on performance. Of course, these engines also have the correct elastomeric parts (gaskets, O-rings, seals, etc) that are compatible with alcohol.

Much different with a boat. Their fuel systems are rarely sealed off from the atmosphere, which is 100% saturated about 3' below their tank vent...at the waterline. Add to that the fact that boats frequently sit idle for longer periods of time in between engine operation, and its easy to see why boats don't work well with ethanol. The tanks "breathe" as a result of atmospheric pressure and temperature changes and each "inhalation" brings in a fresh supply of moist air ready to be absorbed into the fuel. Add to that the fact that older boats (maybe some new ones also) have fiberglass fuel tanks that are not compatible with alcohol, resulting in major deterioration...they basically get soft and dissolve into the fuel over time.

Years ago I heard a marina in upstate New York had a major insurance loss when dozens of boats needed fuel tank replacements due to incorrectly switching to ethanol-fuel. Probably others as well.

6spdC6

Whatever, your car/money do what you want. I will do what is in my best interests!

Tokuzumi

Yeah, that gap between grades is huge. It's maybe $0.20-$0.30/gal in north GA.

JoesC5

I don't have a clue as to what it costs to refine 89 octane at the refinery and then what it costs to add 10% ethanol(to end up with 91 E10 at the retailer) at the local terminal vs just refining 91 octane at the refinery and then selling that 91 octane ethanol free gas at the retailer.

The Top Tier Conoco station near my home is priced at $2.89 for 91 octane E10, this morning. A block up the street, the Top Tier Phillips 66 has their 91 octane ethanol free gas priced at $2.89.

I bet they both of them get their gas from the same refinery in either Oklahoma or Kansas and the same local terminal in Brookline, MO. I can't imagine that the Phillips 66 station is taking a huge hit in profit's just to be price competitive with the Conoco station.

For me, I get 5% better gas mileage burning the Phillips 66 ethanol free gas in my Z06 and in my supercharged Mercedes, plus in my 1956 and 1964 Corvettes and my riding mower, and that is money in my pocket.

JoesC5

I don't get up your way very often, except to drive up to Hannibal, MO for their Corvette show each August. I normally stop at the Sinclair(Top Tier) station in Mexico, MO for some of their 91 octane ethanol free gasoline.

Other stations that sell 91 octane ethanol free gas that I pass by on the way and on my return that are in your neighborhood are....

Camdenton, MO. Cenex; Murphy(Walmart); and Signal.

Colombia, MO. Break Time; three different HyVees; MFA Oil; Sinclair; Mutrux Automotive; Pierpoint Store.

Jefferson City, MO. BP; Cenex; HyVee; Pal's E-Z Stop
.
And while I'm in Hannibal, MO Conoco; Casey's.

I'm fortunate that I have 20 gas stations in Springfield that sell ethanol free gasoline. There are 326 stations in Missouri that sell ethanol free premium.

I do have some trouble finding ethanol free premium stations when I travel to Arkansas. Even though there are 433 stations in Arkansas that sell ethanol free gas many of them are 87 octane, and not 91/91/93 octane.

The number of stations in the US that sell ethanol free gasoline is rising(14,295), but many are only selling 87 octane as that is what the vast majority of cars require.