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E-85 gas in Subie not made for it?


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Just recently, a local gas station had E-85 priced about 50 cents/gallon cheaper then 87 octane gas. Yes, I know that E-85 flex fuel cars use special rubber hosing that doesn't degrade under E-85 use. My 99 with 2.5 motor is not designed for this fuel. My question is.........would a tankful of E-85, now and then, be beneficial in cleaning carbon deposits and just general gunk out of my engine. I am wondering if 2 tank fulls per year would be that detrimental to the rubber and seals in my car's fuel system? Any thoughts ???

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It will run fine, but gas MPG will suck. Fuel hose and rubber fuel parts since the mid 80's have been Ethanol rated so your good there. The Flex Fuel differences come in sensors in the fuel tank to tell it what's in the tank, or others just sense the difference in O2 readings. FF vehicles generally have an E85 tune and a gas tune that switches automatically.. The E85 tune will run the ethanol most efficently. You won't have the E85 tune or the compression/ timing to run E85 efficently and take advantage of it's 106 octane

Edited by matt167
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I wouldnt risk it. The seals and hoses while rated to run some ethanol, were not rated to run at that concentration of it.

You might have problems of your car running too lean as well. When you do an e85 conversion, you normaly want to put in bigger injectors to get more fuel in.

Dont know how many people get the SCCA fish wrapper, 'Sports Car', but they ran an article in the newest one on this very topic.

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I work for a Ford dealership, and it's recommended on the flex fuel vehicles to run a full tank of non e85 through them every 3000 miles to prevent damage to the fuel system and engine. I wouldn't chance it, hell I don't even like running 10-15% ethanol as much as I do.

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I dont remember word for word what they said in the article, but it was something along the lines of it is a leaner, cooler burning fuel, so thats why you

have to step the injectors up if you run it, to get more of the juice for the fire.

 

http://www.sportscarmag-digital.com/sportscar/201305#pg42

 

Thats the link for the article.

Edited by TYLER R
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Injectors will never run that close to their duty cycle in a factory engine. The MAF and O2 sensors togther will be able to adjust the air fuel ratios correctly to keep it from burning up. It will never run efficently as a flex fuel engine will run it.. Ethanol has a bit less BTU's in it than gasoline BUT it's 106 octane. Being 106 octane, engines can get higher compression ratios, more timing/ fuel to take advantage of the octane. When a flex fuel engine switches to run E85, there timing and fuel tables change. Usually nothing more than that.

Edited by matt167
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Taken from another website, haven't verified that the numbers are totally accurate, but should be ballpark:

"...E85 has a different stoichometric air fuel ratio than gasoline's 14.7. The stoich AFR for E85 (at 85%
Ethanol) is 9.76."

 

What this means is that it takes around 50% more E85 to be injected in as compared to gasoline.  Ethanol is a much less energy-dense fuel than is gasoline.  I don't know how many cars' FI systems could cope with that great of a "Trim" value.

 

And, in the end, is saving $0.50/gallon worth using 50% more fuel?

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I have a flex-fuel minivan (which has never seen E-85 here in NJ). The parts different from standard model are pump/regulator assembly, injectors, and stainless fuel rail. The ECU may be different as well, although nothing is different in terms of its control inputs and outputs. 

Edited by avk
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Personally, I wouldn't even think about using any e85 garbage in any car or truck. 50¢ cheaper dosnt add up or compair to the amount of mileage and power loss from using it. I know in both my subarus and my 69 Chevrolet pickup hate even this 10% etho stuff they are forcing on us.

 

If your thinking about cleaning your engine, just dump in a bottle of redline cleaner. You can get it at auto zone I think. Works great. Or use a tank of premium at chevron.

 

Many options. But my advice is stay about from e85.

 

-Prwa

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Bad bad bad idea.

E85 will not effectively clean any deposits from the combustion chamber. It is a cleaner burning fuel when used in a vehicle designed to be able to use it. But cleaner burning does not mean it will make things clean. Use a bottle of fuel system cleaner or run a tank of premium fuel every now and then if you are concerned with keeping things clean.

 

Ethanol also acts as an oxidizer to steel and can degrade steel fuel lines and the tank. This is why vehicles designed to use E85 have nylon fuel tanks and stainless steel lines and fuel rails.

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