Gas Octane

No No, he's no sucker.

It's that CA summer blend that will fuck you up.

 

Three parts 87, two parts 91, one part 93 and a pinch of sugar

 

89,91. I strive to find gas without ethanol.

 

The 4L is already mapped for 87 changing to 91 will make no difference but have at it can't hurt any thing other then the wallet.

 

91 because its ethonal free.....

 

The lack of corn squeezins' in the gasoline seems to be the real difference.

 

You can't just make a blanket statement like that, 91 octane can have ethanol in it just like any other octane, ethanol and octane arent' related at all.

 

Like I just said, are you sure about that?

 

some nutty posts in this thread

didn't read the whole thing yet...

did anyone mention that:

in some cases higher octane does result in better mileage due to: carbon buildup
on the pistons which (in some cases) increases compression in that cylinder,
and you get some detonation and knock sensor retard. using a higher octane stops
the retard which can equate to better mileage in a dirty motor

but that is about it. for all intents use what the gas cap says for best results

 

http://www.exxon.com/USA-English/GFM/fuels_quality_gas_faq.aspx

I think exxon knows what they're talking about, basically says ethanol is in some mandated areas of the country (it has nothing at all to do with the octane level) and says use what the manual tells you BUT in some cases higher octane MAY help.

Also, here's the ethanol map:
http://www.exxon.com/USA-English/GFM/Files/US_Gasoline_Map.pdf

I've never lived anywhere outside the mandated ethanol region so my whole life I've used ethanol gas. You western and souther people have it good, must be nice to have a choice.

 

I am so sick of this thread, everyone has their own opinions, ranging from, makes sense to fucking retarded. I keep clicking on this thread to see if anything actually changes... but it doesn't.

 

Due to the VVT, I believe it can change its tuning. This is based on what I've read and I would like to hear more about it.

From http://en.wikipedia.org/wiki/Toyota_GR_engine

 

Around here its 87, 89, and 93. The pumps have a sign that says may contain up to 10% of ethanol. My question is does the ethanol percentage go down with what grade of gas you get? Say 87 has 10% and 89 and 93 have less than 10%

 

Ethanol level and octane ratings are independent things.

It so happens that some fuel companies - Shell, for example - don't use ethanol in their premium grade (a marketing decision). For some people, buying this kind of premium is a way to avoid ethanol.

It also so happens that ethanol naturally makes fuel less inclined to detonate, so some fuel companies actually rely on it to increase their octane rating (largely a marketing trick, in my opinion, since not every car that likes a higher octane rating likes ethanol). Sunoco Ultra 94 is an example of a gasoline that uses ethanol to raise its number.

That's why there's always so much confusion around the ethanol/octane question.

 

My boat has a 8.1L (496ci) owners manual says 89 unless running fuel that has 10% Ethanol, if running fuel with 10%, 91 octane is recommended.

If Ethanol doesn't change fuel, for the worse, why do I need to run a higher octane fuel if it has Ethanol in it????

 

I don't know, but I'll share an experience I had that might be an example of how that could be: Some years ago, I went to replace the exhaust system on my Bimmer. I had run Ultra 94 in it exclusively, reasoning (wrongly) that higher octane is better no matter how high you go. Where I live, Ultra 94 has ethanol in it. The exhaust pipe was always black and sooty, but I never gave it much thought because the car was new and under warranty. My mechanic told me that they had had a number of BMWs in the shop for running rich, and the reason turned out to be that BMW's knock sensors 'heard' ethanol combustion as pre-detonation and retarded the timing/enriched the mixture to compensate. After the new exhaust went on, I switched to V Power which has a lower octane rating but, around here, has no ethanol. I sold that car years later with not a spec of soot in the exhaust pipe.

Ethanol does change fuel. It lowers its energy content a little bit, and theoretically raises its octane rating a little bit (though not always in a useful way).

Does your boat engine have an ECU that works like the one in a car? If not, it may simply run dirtier with ethanol, and higher octane will prevent detonation of unburned fuel as the plugs foul over time.

 

My boat, 2006 Cobalt, has an ECU and a knock sensor.

I know Ethanol blended fuel absorbs moisture much more rapidly than does straight gas and that because blended fuels absorb water quicker/easier it deteriorates/lowers the fuel quality and octane much faster.

Here is a link to a site that helps you find pure, unblended, gas in your area. They even have and App.

http://pure-gas.org/

Also, here is some good "Gasoline vs Ethanol" information.

When you pull up to a gas pump to buy gasoline, are you aware that what comes out of the pump can vary with the seasons of the year? Is not Gasoline gas? The US government formulates the gas for seasonal changes; summer and winter. One US gallon of gasoline contains 114,000 BTU of energy; depending on the time of year, and depending on what is in the gasoline. It is getting harder to find gasoline's that does not contain 5 to 10% of Ethanol. Ethanol is ethyl alcohol; the kind of alcohol in beverages; beer, whiskey, bourbon, vodka, cocktails, etc.. It takes one and a half US gallons of ethanol to equal the energy in one US gallon of gasoline; the reason... because ethanol only has 76,100 BTU's of energy per gallon. Less energy means less miles per gallon. In 2007 George W. Bush made it possible for gas stations to sell Gasohol (E10) without labeling the pumps; in other words, you may not know alcohol is in the gas. Ever wonder where your gas mileage went?
Gasoline's blended with Ethanol will lower MPG in most engines. The EPA says Fuel efficiency can decrease by 1.5 to 3% but reports of 40 % are not unheard of. In winter, you get less mileage out of a tank of gas; we waste a lot of gas warming up our vehicles, but what about trips? Winter gasoline contains less BTUs per gallon, 112, 500; if you are using 100% gasoline (non-ethanol). A lot of States no longer sell 100% gasoline it at the pumps. They choose Ethanol in the gasoline as a way to meet the Clean Air Act emissions standard. If you have a vehicle that was made before 1990, it is most likely not compatible with alcohol in fuels. Alcohol deteriorates the gaskets and seals that touch the fuel will fail. Alcohol affects the engines timing; makes the engine work harder. Many engine manufacturers prohibit the use of alcohol in the fuel; it is not just cars and trucks; industrial engines, generators, lawnmowers, weed eaters; all gasoline powered engines are affected.
It is the BTUs that allows us to get the best fuel economy. Adding alcohol, of any kind, to gasoline, dilutes the fuel and lowers the heat energy. The pumps provide us a choice of Octane's. The higher the octane rating, the less chance there is of pre-ignition. Octane has nothing to do with the BTU energy content of the gasoline, so use what your engine manufacturer recommends.
Non-ethanol (100%) gasoline is available, but it is getting hard to find. Marinas and aviation fueling stations still carry it because boat and airplane engines require it. Alcohol absorbs water, and water can cause damage.

Gasoline Gallon Equivalent
calculated based on 114,000 BTU's of energy per gallon Reference
FuelGGEBTU/unitGasoline (base)1 US gallon114,000 BTU/galGasoline (conventional, summer)0.996 US gallon114,500 BTU/galGasoline (conventional, winter)1.013 US gallons112,500 BTU/galGasoline (reformulated gasoline, ETBE)1.019 US gallons111,811 BTU/galGasoline (reformulated gasoline, MTBE)1.020 US gallons111,745 BTU/galGasoline (10% MBTE)1.02 US gallons112,000 BTU/galGasoline (regular unleaded)1 US gallon114,100 BTU/gal Diesel #20.88 US gallon129,500 BTU/galBiodiesel (B100)0.96 US gallon118,300 BTU/galBiodiesel (B20)0.90 US gallon127,250 BTU/galLiquid natural gas (LNG)1.52 US gallons75,000 BTU/galCompressed natural gas (CNG)126.67 cu ft900 BTU/cu ftHydrogen by weight0.997 kg119.9 MJ/kgLiquefied petroleum gas (LPG)1.35 US gallons84,300 BTU/galMethanol fuel (M100)2.01 US gallons56,800 BTU/galEthanol fuel (E100)1.5 US gallons76,100 BTU/galEthanol (E85)1.39 US gallons81,800 BTU/galEthanol (E10)1.019 US gallons111,836 BTU/galJet fuel (naphtha) 0.97 US gallons118,700 BTU/galJet fuel (kerosene)0.90 US gallons128,100 BTU/galElectricity33.40 kilowatt-hours3,413 BTU/(kW-h)
States that "do not" require ethanol/alcohol pump labeling:
DC, Indiana, Kansas, Kentucky, Maryland, Michigan, Minnesota, Missouri, Nevada, New Hampshire, New Jersey, North Carolina, Ohio The following States may require labeling; dependent on percent of ethanol in the fuel:
Alabama, Arizona, Arkansas, Colorado, Connecticut, Delaware, Georgia, Hawaii, Idaho, Illinois, Iowa, Louisiana, Massachusetts, Mississippi, Montana, Nebraska, New Hampshire, New Mexico, New York, North Dakota, Oklahoma, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia.

 

I use 89 ethanol free fuel, Saw it from that awesome site pure-gas.org a couple months ago.

 

It might be my imagination but seems like I can feel a very slight improvement in the smoothness during acceleration when I put the occaisional 89 or higher in the tank on my 07 V6. Can't prove it though.

However, on the brands, I have become a believer in the additives used by the major brands in our area (mostly Chevron, Shell, Exxon). This was after my Dad was having trouble with his gas gage not reading so the Ford dealer told him it was a common problem, gas related and to pour in a can of Chevron Techron aditive and that fixed it immmediately.

(Dad always buys the cheapest gas available, like those places where the concrete is always oily looking and the gas smells a little like diesel fuel.)