Hello all,

I live in Connecticut and I have a 2008 C6, F55 with MN6. I use Shell 93octane but the sign on the pump says the gas contains up tp 10% ethanol.

Does the ethanol dilute the octane rating of 93 down to an effective lower octane number? Or does it have no effect on the octane rating?

Since I have never run the car on any other kind of gas, I can't tell if I am getting all the performance out of my LS3 or not.

I'd appreciate any comments from tuners or others who have tried to tweak their car's performance by experimenting with various types of gasoline.

Thanks for your help.

jptonks

 

In CA we also have up to 10% ethanol, only premium is 91 octane. The octane rating is still valid though, so no worries. The ethanol just hurts your fuel economy a bit. And FWIW, ethanol actually raises the effective octane rating. Not sure if it's re-rated to account for that, but it definitely doesn't lower it.

If you really want all the performance the fuel will give you, you'll need to retune. Even the 91 out here is enough to give you an extra kick. With 93 you've got even more potential.

 

The problem is if it gets much more than 10% you run the risk of damage to the gaskets, seals, etc. Who knows who is mixing the percentages. E85 or flex fuel cars have components that withstand ethanol. IMHO

 

All cars built in the us since 1980 have been oked to use 10% Ethanol (E10). Ethanol octane by itself is @113. Ethanol mix will yield slightly more power as ethanol contains a higher % of Oxygen. Emissions will be reduced also. Ethanol mix will help prevent premature detonation and cold weather icing as ethanol absorbs water out of you gas tank.

 

Also, your owners manual should state you can use this stuff and should warrant the use of gas with E10. I'll have to see if it's in there.

Here's a good website- http://www.drivingethanol.org/ethano...g_ethanol.aspx

 

e-85 is rated at 105ish octane

 

Everybody has 10% ethenol gasoline. It has no effect on anything. 93 octane is 93 octane and the vehicle runs the same.

I don't know about the E-85 being 105 octane. I have a flex fuel E-85 Silverado and without tweeking the numbers I think E-85 has to be about 28% cheaper than gasoline to get the same miles per dollar out of it. Right now it isn't and never has been so I never burn E-85. E-85 is a bust, doesn't work and is just driving up the price of food dramatically. The range out of a tank of fuel goes way way down with E-85 as well.

 

We still have a few stations in TN selling pure gas. I does effect gas milage, my dd looses 3-4 mpg's on the 10% blend...I have never used ethanol in the Vette....

I ordered one of these this week....

http://www.theoutboardwizard.bizhost..._test_kit.html

 

Worth reading...

http://www.fuel-testers.com/understa...l_percent.html

Gas containing ethanol (alcohol) content over 10 % will have negative effects on your engine's parts and performance.
E85 can only be used in engines designed to run on this high alcohol fuels (FFV's -Flex Fuel Vehicles, "Green" cars).

Understanding Effect of High Alcohol Content on EnginesInterpreting and Understanding TEST RESULTS


Note: The following information is guidelines only, engine affects from alcohol fuels will vary. Consult a certified mechanic for more information. Always follow equipment's fuel recommendations and review your owner's manual and warranty statements for fuel recommendations.


Alcohol Content Results
Effects of percent (%) alcohol on engines.


Up to 10 % alcohol = Legal limit for E10 -Safe for most engines.


11 to 15 % - * Risky - Use with extreme caution. Engine performance problems will usually occur, eg. stalling. Fuel should be drained (discarded), and replaced with fresh gasoline.


Although possibly unsafe, if only a small amount of fuel is left in tank tests over 10% alcohol,(eg. less than a 1/4 tank full), filling the tank with a high octane (93) fresh gasoline can be considered. After filling tank, check fuel again to check alcohol percentage has decreased to a safe level. See important notes below.


16 % to 25 % = Very Risky - Do Not Use - Will experience varied engine performance problems, including unable to start, frequent stalling, difficulty accelerating, and more. Will reduce life of engine.
Recommend fuel be immediately drained and discarded. Do not run your engine on this unsafe level of alcohol.


Damage to your engine and parts will occur, sometimes immediately. How soon this occurs is dependent on several factors, including age of engine, type of engine, parts used, and condition of engine. See important notes below.


26 % to 40 % Severe risk and danger - Do Not Use - Affects will be same as listed above for 16 to 25 %, but damage will appear much sooner, sometimes immediately after running one time on this dangerously high alcohol content level.


Performance problems will be greater, and older or poorly tuned engines most likely will be unable to start on this very high level of alcohol. Black smoke from engine will be apparent. Fuel discoloration and a strong odor is proof that gas is contaminated.


The dirtier your engine, the greater amount of gunk released will be noticed. Engines that have older, dirty parts will notice clogged fuel filters very quickly. See important notes below.


Over 40 % -Engine probably will not start. Do not use - Severe damage will occur. Damage to engine will be permanent, engine may not be repairable. See important notes below.
VIEW NECESSARY ETHANOL ENGINE PRECAUTIONS

 

Most places in the surrounding areas only sell 91 and it's "pure gas", 89 is the 10% blend. I did find a place last week that has 93 with the 10% blend and I filled up with it. I'm seeing a small decrease in MPG, 1-2 mpg maybe, but the car as a little more kick so I'm happy with that trade.

 

Yep, in So. Cal the gas has 10% ethanol and is only 91 octane.

 

I must disagree with the statement that ethanol production has run up the price of food.
Ethanol comes from "field corn" and most corn used in food product comes from "sweet corn". Only 5% of field corn is used in food production.
The US had 1.8 billion bushels of surplus corn in 2007. Plenty to go around.
9 billion gallons of ethanol will be produced this year and if ethanol was not available you would be paying between .40 to .58 cents more for a gallon of gas. Ethanol at the rack -Us avg. today was 3.34$ per gallon.

Ethanol can also be produced from Biomass which is wood fiber, grasses, corn stalks etc. This is called cellulosic ethanol.

Food prices have been driven up in most part by fuel surcharges and the increased cost of fuel resulting in much higher transportation costs.

The demand for more corn has put nearly 250,000 farmers back to work in the US and they all want a black corvette !!!

 

you are one of the few that doesnt see the connection between ethanol and food prices

there are few cellulosic ethanol plants - none large enough to support gas additives

 

Always easier to blame it on the farmers because who cares--we get our food at the grocery store, besides farmers should all wear overalls and be fairly poor. Most people in this country have absolutely no understanding of production agriculture and what it requires in management skills as well as inputs.

 

I did some research before I chose to run E-85 in my 8 second street car. It is 105 octane but the main reason I chose to run it is because Im not running an intercooler on a 1400 HP street engine.The cooling effects are much greater on the E-85 than gasoline. I agree that it takes roughly 28% more fuel and that is one thing that people need to be sure that their fuel pump , Injectors ETC can move the additional fuel needed to be jetted properly. Here in Indiana the closest E-85 station to me is about 4 miles. After doing an online search I found that 99 stations in Indiana sell E-85 and the one closest to my house happens to be the most expensive. They sell it at .50 cents cheaper than 87 unleaded. Some stations in Indiana sell it as much as 1.25 per gallon less than 87unlead.
I agree with an earlier post that unless its 30% cheaper at the pumps then its a take it or leave it call. BUT.......If you can properly set up your car to run on it and you have access to it then the performance gain might very well be worth the trouble. I hear of 12 second cars picking up 2 tenths. I know my 106mm turbo big block loves it(8.90@166.58 @3800pounds) and runs 185-190 degrees on 85 plus days. I think its really up to the individual driver. Have a good one!

 

10% ethanol will not hurt your car. There is no way it affects mileage by 3-4 mpg. It might affect mileage by a few tenths of a mile per gallon but the cost savings makes it cost effective. E85 is o.k. in vehicles that are tuned and built to handle it but it is not cost effective.

Ethanol for cars has affected the price of food. Don't forget that corn is used as feed for animals. so whether it's "field corn" to feed animals or it's "sweet corn" to consume it's still needed for food.

Here is a study on MPG and CPG for unleaded fuel vs various amounts of ethanol fuel.

 

You too have missed 'getting' it. The cost of food has little to do with ethanol, it is as the poster states, the general rise in fuel prices. We have excess corn. Can produce more, if they release the CRP land to actually grow corn, etc. Can we produce enough to eliminate our dependence on mid east oil, NO. But, any reduction is worth the cost, because believe it or not some day we run out. That's what people need to 'get'.

 

True that field corn is used for animal feed. However, only 5% of the total corn production in the US was used in Ethanol production in 2007. Food prices are up significantly higher.

One of the by-products of the ethanol production is distillers grain which maintains the proteins minerals and oils from corn and is an excellent food source for animals. Ethanol production removes the starches/sugars and CO2. The process only produces @2.8 gals of ethanol / bushel so there is alot of distiller grain left for the livestock!

Disproportionately high fuel surcharges are driving food costs and driving up the price of any good or service with a transportation ingredient! Even my garbage man has added a fuel surcharge.

 

I have done several checks on my 2007 3.8 Buick LaCrosse using 10% ethanol and 100% gas. Same trip, same mph, same distance, with gas 31-32 mpg with 10%, 27-28 mpg's.....Around town 21-23 on gas 16-18 on ethanol

I haven' tried the ethanol in the 08 Vette yet but a 180 mile trip today to the Museum and the plant returned 29.9 mpg with the A6....

 

Using food for fuel is unethical..