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Originally Posted by 1999 White C5 Coupe
E85 fuel contains about two-thirds the energy of non-ethanol unleaded gasoline (gallon for gallon).
What is rarely discussed is that vehicles designed to run on E85 fuel get significantly less mileage using E85 fuel compared to using non-ethanol unleaded fuel (or fuel that has 10% or less ethanol).
Why would anyone want to convert a vehicle to run on E85 fuel and reduce their fuel mileage significantly?
GM is touting the number of new vehicles designed to run on E85 fuel, but the company does not talk about the reduced mileage.
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(Positive) facts about E85:
1. It is not corrosive to the fuel system or the engine. This is a myth and ethanol is often confused with methanol, which actually have corrosive properties. I´ve run my car for well over two years on E85 without a problem. Some models before 1988 on the other hand may have some parts that is not ethanol resistant. If we are talking Volvo´s, then this mainly applies to the non-electronically injection systems such as K-jet etc. Most cars with electronical fuel injection (EFI) should be resistant to ethanol. Some people say it would kill your engine right away and that you should buy there racefuel instead (of course they say )
2. It is not as harmful to the nature/environment as gasoline or any other petroleum products for that matter. Ethanol is made out of renewable energy resources such as crops and trees to name a few things. The carbon dioxide that an ethanol powered car emits is not contributing to the greenhouse effect, but is taken up by the plants and is being "re-used". The carbon dioxide then goes around in a closed loop. Gasoline on the other hand is made from oil that comes from old dinosaurs , plants and other stuff 100 000 of years ago, and it doesn´t take part in the closed loop but only adds to the amount of greenhouse gasses. Ethanol is also easily bio-degradeable if it should leak into our environment.
3. E85 is 104-105 octane and therefore it´s more knock-resistent and can tolerate more boost or a higher CR.
4. E85 cools the intake charge more and therefore it´s more knock-resistent and can tolerate more boost or a higher CR. And it also makes the engine run cooler and to some degree, even safer.
5. E85 is in most cases at least 5% more effícient than gasoline at the same lambda value (up to 25% more efficient on some cars optimized soley for E85). Mill your heads
6. Since E85 has very good cleaning properties as well as leaving behind a rest-product of water, it is cleaning the fuel system and it will keep the injectors nice and clean. The combustion chambers, valves, ports and the exhaust will also be clean(er), almost like the car had water injection.
7. In most cases it will cost less $/mile to run on E85.
(Negative) facts about E85:
1. Cars running on E85 have some trouble starting when the engine temperature drops below +5*C. Cars running E100 (not very common) have some trouble starting when the intake (the air) temperature is below +15*C. This is easily solved by using an engine heater in the winter, electrical or fuel-heated (this is recommended on all cars regardless of fuel to get better mileage, less wear on the engine and less impact on the environment etc., but that is another matter to discuss and will not be brought up here...). Some people also adds a little extra gasoline to the tank of E85 to help with cold-starts.
2. Since cars running E85 requires roughly 30% more fuel, a tank of E85 will not get you as far as a tank of gasoline and you will have to refuel more often. This is often disregarded by E85 users who learn to live with it because of the economical gains.
How much will my miles per gallon of fuel drop with E85?
The only negative to E85 is that it gives a lower fuel milage on a gallon for gallon basis to gasoline. The actual difference in energy content between straight gasoline and E85 is about 27%.
The drop in milage is not as significant as you would think based on that difference due to the higher effeciency of the ethanol as a high performance fuel.
The lower milage is not really a big deal, ethanol has lower energy per gallon but your reduction in milage is not nearly as large as that difference would imply. Due to the higher torque,you use slightly smaller throttle openings to get the same level of preformance, and due to the greater quantity of combustion products (more moles of gas) per lb of fuel the engine effeciency actually goes up slightly.
***Thanks fo RUNN at LS1tech.com for the info!***