Also, ethanol has 60% of the heat energy as gasoline, requiring a different fuel mapping strategy in the computer. OEM vehicles that are capable of operating in multifuel mode (Flex Fuel Vehicles) have fuel line sensors which determine the fuel being used and alters the fuel mapping strategy.
Mike Halloran is correct, ethanol has a nasty habit of eating the gas tank, fuel pump, all the rubberized fuel line components, the fuel injectors and seals, and if allowed to puddle, can start eating away of any aluminum and related alloy components. I made a lot of money cleaning up fuel systems of the early 80's with E-10, just imagine what E-85 would do?
Franz
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I have heard that methanol is significantly more corrosive than gasoline and the ethanol (which is a componenet of E85) is only slightly more corrosive than gasoline. Is there a way to manufacture rubberized components resistant to corrosion from ethanol? Also, how long does it take for ethanol to eat through the engine components?
Ashelin
PS: By the way Franzh, were you referrring to using pure ethanol in the gasoline tank?
Sure, there is a way to manufacture E85- resistant elastomers. They're used in vehicles labeled for flex fuel use.
I have no specific data on ethanol and the specific elastomers used in fuel systems, but my experience with other solvents and other elastomers says you can expect serious attack in less than a day.
To my knowledge, all current vehicles are manufactured with alcohol compatible seals. I've got a circle of friends here who run E85 in their non-E85 vehicles with excellent results. The mileage does not drop as greatly as conventional wisdom says it would. Your computer will prompt the "check engine" light, mainly due to the higher oxygen content of the fuel.
Most of the OEM's have service bulletins warning their service departments to check for ethanol fuel in the tank when encountering fuel system related problems.
To the best of my knowledge, only vehicles which are listed by the OEM's as a flex fuel vehicle operate properly on E-85. The check engine light coming on usually indicates a fuel trim code fault, insufficient injector pulse width to supply enough fuel within parameters.
The oxygen thought may be true, if the engine leans out due to insufficient fuel, there is excess oxygen during combustion, not necessairly due to the oxygen content of the fuel (although it does indeed have more). The stoich ratio of E-85 is much lower than gasoline.
Franz
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My experience with E85 is that for modern OBDII cars, up to 33% E85 is not a problem. I have been running high fuel ethanol mixes for 2 years now in a 2002 WRX with no fuel system problems of any kind.
All the modern cars are warranteed to be save at 10% ethanol and my experiment leads me to believe that they are essentially ethanol safe as far as materials go.
You need to bump fuel mass flow by 27% to get proper mixture, but the fuel milage does not drop any where near the amount you would expect based on the specific energy density of the fuel.
On 100% E85 you can expect about 5% increase in power and torque, and the engine needs less throttle got achive the same results. Higher octane allows the ECU to use more favorable timing closer to MBT advance, and it can run leaner mixtures under load without hitting knock limited performance.
The real world results in my case is I get about 92% of my gasoline fuel milage on 100% E85 with better power and drivablility.
I am not 100% convinced that "all modern cars are warranted to be safe at 10% Ethanol". Most moden cars (if they are ever to be sold in California etc) will be tested/warranted with RFG2/CARB Phase2 gasoline which is 10% MTBE. This is used as a standard test & sign off fuel for OEMs.
The new RFG3/Phase3 fuel will use 10% ethanol as an alternative oxygenate but this is yet to occur, I believe. Most cars in production will not have had much exposure to this fuel since when my gasoline days ended (4 months ago) the brew hadnt been finalised.
The oxygenates will of course cause you to run lean, if your engine is of an adaptive EFI nature then there is the risk that you hit the clamp of your fuelling adaptions running v.high O2 content in your fuel. Infact even worse than that the high speed/load operation may mean that you are far to lean when running open loop fuelling control.
Hopefully if you are 'leaning out' OBD2 should pick it up and put the check engine light on...However you may not know about it if you are just within the threshold during closed loop operation but way out during open loop.
