I have been looking into the use of E-85 for use in my Trans Am for a few years now and the recent introduction of this fuel to a few of our areas Mobil stations has got me especially excited. Ethanol seems to be especially optimal in forced induction applications.
Update! I have been using ethanol daily for over a year now. I recently had a non fuel related issue that is a common failure on my car that has me tearing down the engine. What I found were cylinder heads that were much cleaner then I have seen on 90k of gasoline use. Piston that have the carbon flaking off as you can tell it was probably there for a long time before the ethanol. Cylinder walls look like new with visible crosshatching from the original hone. I was worried about the cylinders due to possible wash out. With some prior tuning my car still started fine on 80% ethanol in sub freezing temperatures after sitting for 3 months. TurboTravis is also doing some experiments to expel the myths of ethanol you may find in this thread. He has also been using ethanol as well as others in the area with no issues as of yet.
The facts
E85 stoich is ~9.7:1, depending on the blend of your favorite gas station. Typical gasoline stoich is 14.7:1.
14.7:1 = lambda 1 for gasoline
9.7:1 = lambda 1 for e85
All widebands read lambda and then multiply by a constant for a given fuel type to calculate an air/fuel ratio. Have you ever seen where you select the fuel type for a wideband’s units, and the displayed a/f changes a LOT even though the car is running the same?
If you set your wideband units to gasoline, it takes whatever lambda value it reads and multiplies it by 14.7. So, if your wideband is configured to read gasoline a/f, then just divide the a/f displayed by your wideband by 14.7 to get the lambda.
The good
-105 octane pump gas
-E85 does not detonate.
-$2.65 per gallon
-higher rate of expansion = more cylinder pressure.
-faster flame speed = less necessary ignition timing advance.
-High latent heat of vaporization. Greater chemical cooling effect than gasoline.
-greater acceptable tuning range for max power and torque A/F ratio.
-More exhaust gas per volume of intake charge = faster turbo spool?
-clean burning, leaves no carbon deposits in engine and better for environment. No hydro carbons
-made of corn, renewable energy source
-Burns at same acceptable lambda value as gasoline. Factory oxygen sensors can still meter STFT and LTFT
The bad
-Low energy density. Requires about 30-50% more fuel to reach stoich a/f ratio = lower MPG.
-Upgrades to fuel system to flow more volume. Pump, injectors, lines and rails.
-Prone to preignition in spite of higher octane level. Colder plugs and nonprojected tips required in high CR, Nitrous, FI.
-Large fuel volume in combustion chamber requires hot spark and tight plug gaps.
-Availability in our are is low. only 5 stations that I know of currently carry E85.
-May not be compatible with some fuel lines, pumps, injectors or carbs that ethanol is corrosive to. Usually older vehicles.
-Ethanol mixes with water that dilutes the fuel and can cause oxidation of soft metals and steel.
-Contaminants from supply tank or vehicle tank may be consumed by engine.
-Oxygen sensors use lambda values (ratio of unburnt exhaust gas oxygen content) so A/F gauges will not read correct A/F ratio for ethanol.
-Ethanol content can vary greatly between station to station. This is why factory vehicles are “flex fuel” to compensate. Content can be 65 - 90%
This info is from a thread on LS1TECH.com. Some of this relates to LSX engines but most info is universally relevant to all engines
"Soo you want to use E85? I´m getting alot of question about E85 and i try to answer but i dont have the time to answer everybody. Soo i have put together some info for you… First the info you need and later a small howto.
There is tons of info about sparktiming and best AF to use with Gas but on E85 it is almost nothing, We have to work together here and share our experiences.
Be patient please, more info will be added
First of all, what is E85?:
E85 consists of 85% ethanol and 15% additives. The additives vary a lot depending on where you live and time of the year. But roughly, the 15% additives is mostly made up of gasoline, additives that helps the engine to make a complete burn, additives that helps the engine start when it´s cold and additives to color the fuel and the flame (so you know what substance it is, and also to help you see that it is really burning).
(Positive) facts about E85:
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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 )
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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.
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E85 is 104-105 octane and therefore it´s more knock-resistent and can tolerate more boost or a higher CR.
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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.
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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
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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.
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In most cases it will cost less $/mile to run on E85.
(Negative) facts about E85:
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Cars running on E85 have some trouble starting when the engine temperature drops below +5C. Cars running E100 (not very common) have some trouble starting when the intake (the air) temperature is below +15C. 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.
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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.
Technical facts about the mentioned fuels:
E85 requires 39% more fuel to reach stoich even if that is not what you may come up with when doing calculations based on the table below. This is because the injector flow is slightly different when using E85 among many other things I can´t really think of at this time (will be added at a later time).
Fuel … AFRst … FARst … Equivalence Ratio … Lambda
Gas stoich … 14.7 … 0.068 … 1 … 1
Gas max power rich … 12.5 … 0.08 … 1.176 … 0.8503
Gas max power lean … 13.23 … 0.0755 … 1.111 … 0.900
E85 stoich … 9.765 … 0.10235 … 1 … 1
E85 max power rich … 6.975 … 0.1434 … 1.40 … 0.7143
E85 max power lean … 8.4687 … 0.118 … 1.153 … 0.8673
E100 stoich … 9.0078 … 0.111 … 1 … 1
E100 max power rich … 6.429 … 0.155 … 1.4 … 0.714
E100 max power lean … 7.8 … … 0.128 … 1.15 … 0.870
Ethanol reaches max torque at richer mixtures than gasoline will.
The term AFRst refers to the Air Fuel Ratio under stoichiometric, or ideal air fuel ratio mixture conditions. FARst refers to the Fuel Air Ratio under stoichiometric conditions, and is simply the reciprocal of AFRst.
Equivalence Ratio is the ratio of actual Fuel Air Ratio to Stoichiometric Fuel Air Ratio; it provides an intuitive way to express richer mixtures. Lambda is the ratio of actual Air Fuel Ratio to Stoichiometric Air Fuel Ratio; it provides an intuitive way to express leanness conditions (i.e., less fuel, less rich) mixtures of fuel and air.
As you can see from the table shown above this section, the ideal target AFR´s under boost for both gasoline and E85 are listed. For gasoline it´s 13.23-12.5, and for E85 it´s 8.47-6.975. However, with E85 you will not need to richen the mixture under WOT/boost as far as 6.975 or beyond. It does not need to be proportionally richer when compared to gasoline.
Why? Again, Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs. And at such a low AFR as 9.765 (lambda=1 on E85) or lower the fuel cools pretty good, don´t you think so?
Many people with some experience in mapping an ECU for use with E85 says that as high AFR as 8.5 or lambda=0.80-0.85 works well. No need to go to the extreme end of the useable scale to get safe power. It only uses a lot of fuel without giving any benefits.
E85 burns faster than gasoline at best mixtures so it is an inherently more effecient fuel. It also produces more exhaust gas for a give weight of fuel air mix giving higher average cylinder pressures inspite of lower EGT’s. With streight E85 in a properly tuned car its good for about +5% power / torque increase. I suspect on a turbocharged car the benefit is larger.
Since you don´t have to richen the mixture as many percent (proportionally) as you have to on gasoline, you can make more power without having to use as much fuel.
How does ignition timing change on E85 ?
Timing on ethanol blends will not change very much. MBT timing for both gasoline and E85 are very nearly the same at light to moderate engine loads. At high engine load the E85 will want just slightly more advance. The big difference will be fuel/air mixture. The E85 will give improved torque with much richer mixtures than gasoline. Both gasoline and E85 will give best thermal effeciency at about 15% rich of stoich, so the equivalent of 12.78:1 on gasoline would be about 8.5:1 on E85, but E85 will continue to give better torque numbers up to about +40% rich of stoich or 7:1 mixtures, so on a utec you would want to richen up your WOT high load cells and add a tweak of timing to get the most out of E85 from what I’ve read. I run my car on 8.3:1 right now. I have tried much richer mixtures but i have not compared it on a dyno yet.
Quote:
Are you sure you don’t mean that E85 will allow more advance?
Just passing on what I’ve found in the various sources. Logically you are correct, but one source says simply that MBT timing is the same for E85 and gasoline, and another report says at low loads the E85 and gasoline like the same MBT timing but at high loads MBT timing for the E85 is slightly more advance.
I suspect this is due to them not running ideal max power mixtures but cannot confirm it. Burn speed for E85 changes quite a bit with mixture, so if they were just a little bit lean or rich of ideal the burn rate would be lower.
Lots and lots of variables not well covered in some of the sources and in general they are focusing on emissions issues not max power torque so that would incline them to use less than best power timing advance. In a couple of the reports they also had limited control authority over timing and may not have explored the extremes very thoroughly.
I have also read that E85 burns much quicker than gas at rich mixtures soo if you have your timing advanced and go WOT you could get powerloss (And you micht not pick up any knocks) because of the burnspeed being to fast.
My experience with E85:
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Better power (cooler intake charge, higher octane and the fact that it is cleaning the engine pretty good).
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Smoother power and better stability at part-load.
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After only 50 miles the tail-pipe began to get a lighter color. It was black inside before, now it´s brown and very transparent. My pipe is chromed and now you can see the chrome on the inside as well. When I have driven the car for a couple of 100 miles more I will tell you if it has got any cleaner inside.
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The sound from the engine is different. It sounds more powerful.
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The smell from the exhaust is much nicer. I cant describe the smell, When the car is hot i dont smell anything wierd. BTW i drive without cats.
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The ethanol is cleaner and does not cause problems and if used in an E85 mix it will promote better lubrication of the parts in contact with the mixture and thus, will increase the engine useful life and ensure a significant increase in fuel economy.
Will my O2 sensor work with E85 and high ethanol blends?
The O2 sensor is not an issue, all it cares about is if your at stoich combustion at low throttle settings, it doesn’t much care how you get there, so no need to change it. There is a thread about this on this forum somewhere where i explane this… (see if i can find i later)
What about oil contamination?
Modern lubricants, especially the synthetic oils are much much different than the oils used during those studies, and modern engines run at higher temperatures today which will quickly boil any traces of alcohol out of the oil.
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.
Will a wide band O2 sensor accurately read fuel air mixtures with E85 blends ?
To get an accurate AFR reading you need to switch the meter to Lambda or equivalence ratio setting rather than AFR. Most O2 sensors assume you are running gasoline and will report a stoichimetric mixture as 14.7:1 which is the proper value for gasoline. E85 has a Stoichemetric mixture of between 9.7 - 10:1 and a max power mixture of about 6.98-8.5:1 or so, where with gasoline it is 12.5:1-to 13.1.
If you must use an O2 sensor that only reports gasoline AFR information simply divide the numbers it reports by 1.47 - 1.50.
The O2 sensors would still work. They don’t understand AFR, they only understand rich/lean. If you are using regular or E10 the stoich AFR is ~14.7:1 (as you well know) and when the O2s are switching, this is the AFR it is indicating. When you are using E85 (AFR 9.765:1), the O2s will still work, switching between rich/lean. It’s just that the point they are switching at is 9.765:1. You have to know what fuel you are burning to properly interpret the information the O2 sensors are providing.
Lambda 1 is always Lambda 1 no matter what you drive your car on, the o2 sensor doesn´t care if the AFR are 14,7 or 9.765… it measures the available o2 in the exhaust gases.
Is Ethanol less corrosive than Methanol?
Methanol is much more corrosive than ethanol. It attacks certain soft metals that are not much used in modern fuel systems. Years ago, the carburators were made of un-anodized aluminum and if methanol fuel was used, you had major problems with electrolytic corrosion between the aluminum and copper components used in the fuel system, since they were in continous contact.
That sort of corrosion only occurs when you have a current path between the dissimilar metals AND, a conductive path through the fluid in the system.
In Brazil where they have run high ethanol fuels since 1939, they found that to convert older cars designed for gasoline, long before ethanol blends were common, needed several changes to convert the cars over. This led to changes in valve materials, piston rings choices, nickle plating of the fuel tanks etc.
Modern cars in the U.S. are designed for use with ethanol up to 10% concentration in the fuel. That has led to several changes in component materials over the last 30 years that the U.S. has used ethanol enhanced fuels. All modern fuel lines and such are designed with the expectation that some ethanol will be in the fuel.
What about fuel system corrosion?
Corrosion does not appear to be an issue with modern OBDII cars. They are all certified by the manufactures to be safe to use on 10% ethanol fuel blends, and industry insiders say they are safe for much higher percentages. You don’t install components that are “sorta safe” with a chemical, you put in a fuel hose etc. that is ethanol safe for concentrations well above what you expect to use. Not to mention that folks have been talking for years about raising the ethanol level to 20% or more.
Many years ago there were studies that indicated engines that ran on alcohol ALONE as a fuel, had issues with lubrication and valve seat wear. Keep in mind, those studies were done a long time ago, when engine oils were much less sophisticated than they are now, and some engine manufactures in the 1940’s,1950’ and 1960’s made stupid engineering decisions and did not use hard valve seat inserts like stellite in the cylinder heads. This resulted in valve seat recession problems if you did not have lead additives in the fuel to protect the valve seats."
"To sum it all up
Why is Ethanol a better fuel ?
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It has a much higher evaporative cooling power than gasoline so the intake air charge in the cylinder is significantly cooler that it is with a comparable mixture of gasoline — that means higher VE.
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Its octane as blended in E85 is about 100, its blending octane when added to gasoline is rated at 118, so it is a very cost effective octane booster.
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Ethanol burns faster than gasoline but has a slightly longer ignition delay during the slow burn phase of combustion so the engine does not do as much negative work fighting rising cylinder pressures due to large ignition advances. The total ignition advance for E85 is almost identical to the ideal advance for gasoline so it does not cause the PCM problems when you mix them.
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At proper mixture you actually are releasing more energy in the cylinder due to the higher quantity of fuel you can burn. ( Ethanol can burn effeciently at much richer mixtures than gasoline can) That means about a 5% increase in energy release all by itself.
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Peak combustion pressures are actually lower for ethanol than for gasoline but the cylinder pressures stay higher longer, so you have more (longer) crank angle that is usable by the engine. This lower peak cylinder pressure also helps with detonaton control.
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Theorethically, the gain is 5% just by switching fuel. 350 hp X 5% = 15 hp, plus what can be gained from timing."
Runn-www.ls1tech.com*
-UPDATE: Frequently asked questions and answers about E85
This may not be fact. But most of it makes sense to me…
- E85 Ethanol is corrosive
Yes ethanol is corrosive, but not very much. Gasoline is corrosive too. Ethanol is biodegradable in water. So it has a tendency to contain and attract water. It is not the corrosive properties of ethanol that can cause damage to your vehicle; it is the water which can rust a vehicle’s fuel system from the inside out. Today’s vehicles (since mid 1980s) have fuel systems which are made to withstand corrosive motor fuels and rust from water. Also today’s distilling processes are superior to way back when. We now have better techniques for drying out ethanol or reducing the water content.
On side note, gas contains water too. Ever hear of dry gas?
- If I put E85 in my gas tank, it will eat it away.
If your car was built in the old days, it was had a lead coated, steel tank. The water in ethanol would cause the tank to rust from the inside out. The government mandated that all gas in the USA contain 10% ethanol to help reduce tail pipe emissions. In the 1980s, automakers made vehicles with fuel systems to be ethanol and rust tolerant. Gas tanks began to contain polymers and Teflon which are extremely durable.
- If I put E85 ethanol in my non-Flex Fuel vehicle, it will ruin it.
One tank won’t hurt. Some dealers are spreading rumors and charging $300-$3000 for one tank of accidental E85 use. This use may cause misfiring and a rough ride. Your check engine light will come on. If you should accidentally or on purpose put E85 in your vehicle, drain the tank, put in regular gas and all will be well. If you use E85 without a conversion kit or non-Flex Fuel capable vehicle for an extended period, you can damage your engine.
- Ethanol will burn up my engine.
Ethanol has a lower ignition point than gas. Ethanol has about 115 octane and E85 has 105 octane. It burns cooler and will extend engine life by preventing the burning of engine valves and prevent the build-up of olefins in fuel injectors, keeping the fuel system cleaner.
- Ethanol will ruin gaskets, seals, rings and more.
Running 100% ethanol or alcohol in an engine can cause damage to cork products.
The rubber neoprene used in the last 20 + years is resistant to the drying effect that ethanol may have.
Today’s vehicles are built to withstand the corrosive effects of water in ethanol and gasoline. Any vehicle built since 1985 will have no ethanol related issues. Older vehicles that used more steel in the fuel systems or cork gaskets may have issues from long term exposure to water.
Vehicles in Brazil have been using ethanol for 30 years and they are completely free from using any foreign oil.
- E85 will eat my rubber fuel lines.
This is another myth from the old days. Rubber technology has significantly advanced so the concerns of a 20 year old car or newer having issues like this are extremely rare. Plus the 15% gas will help keep lines lubricated.
- E85 will destroy my fuel pump.
E85 won’t destroy your fuel pump. If you convert a high mileage vehicle to Flex Fuel, the E85 will cause the sediment in the gas tank to dissolve and then get sucked up by the fuel pump. It is believed that this sediment may shorten the life of the pump of your higher mileage vehicle (100,000+). We have had no reports from customers with damaged fuel pumps.
Video Proof: E85 does not harm engine, fuel lines, fuel pump, injectors, etc.
We do not recommend using E85 in your vehicle without an E85 conversion kit.
- It takes more than a gallon of energy to make a gallon of E85.
This was true at one point in time. Today’s advanced technology and distilling processes actually create considerably more units of ethanol than units of energy used. The processes continue to advance and the ratio will continue to increase.
- E85 Ethanol is worse for the environment than gas.
There have been some people who have published reports stating that E85 is worse than gas for the environment. They have yet to show any scientific proof or case studies that support their claims. Because E85 is cleaner than conventional gasoline, it emits less hydrocarbons, nitrogen oxides, carbon monoxide and hydrogen. E85 reduces carbon monoxide emissions by as much as 70 percent — and less carbon monoxide helps reduce ozone formation and greenhouse gas levels. According to EPA, gasoline is the largest source of manmade carcinogens. Ethanol reduces overall toxic pollution by diluting harmful compounds found in gasoline such as benzene and other aromatics.
- Using E85 ethanol will get 50% less mileage per tank.
There are some stories floating around about 50% reduction in mileage or twice as much ethanol is needed. Some of the automakers who introduced Flex vehicles did a terrible job with the fuel management systems that mileage did decrease as much as 50%. After some trial and error, the automakers have significantly improved their Flex systems and mileage conservation is within reasonable losses such as 5-15%. Conversion Kits like the Full Flex have been around for over 20 years. Realistic losses range from 5-15% as well.
- Vehicles need more E85 ethanol so there is less power.
It is true that a vehicle does require more E85 than regular gas since the amount of energy per unit of ethanol is less than that of gas. Ethanol has a lower ignition temperature so the engine overall will run cooler increasing power. It also burns slower so instead of just burning out in one violent explosion forcing the piston down, it continues to burn the entire length of the piston stroke expanding gases more evenly and smoothly. So running E85 will give any engine more power over any pump gas. Also E85 is 105 octane. Gas comes in 85, 89 and 91 octane. The 105 octane of E85 will help to eliminate knocks and pings. All of these benefits will make an engine run smoother and quieter.
- Won’t E85 production deplete human and animal food supplies?
No, actually the production of ethanol from corn uses only the starch of the corn kernel, all of the valuable protein, minerals and nutrients remain. One bushel of corn produces about 2.7 gallons of ethanol AND 11.4 pounds of gluten feed (20% protein) AND 3 pounds of gluten meal (60% protein) AND 1.6 pounds of corn oil.
- Ethanol does not benefit farmers.
The ethanol industry opens a new market for corn growers, allowing them to enjoy greater profitability. Studies have shown that corn prices in areas near ethanol plants tend to be 5 to 10 cents per bushel higher than in other areas. This additional income helps cut the costs of farm programs and add vitality to rural economies. The additional profit potential for farmers created by ethanol production allows more farmers to stay in business — helping ensure adequate food supplies in the future. Ethanol production also creates jobs, many of which are in rural communities where good jobs are hard to come by. A 2005 study by LECG found the ethanol industry powered the U.S. economy by creating more than 147,000 jobs, boosting U.S. household income by $4.4 billion and reducing the U.S. trade deficit by $5.1 billion by eliminating the need to import 143.3 million barrels of oil. Those kinds of numbers help farmers and all Americans.
- Ethanol production wastes corn that could be used to feed a hungry world.
Corn used for ethanol production is field corn typically used to feed livestock. Wet mill ethanol production facilities, also known as corn refineries, also produce starch, corn sweeteners, and corn oil — all products that are used as food ingredients for human consumption. Ethanol production also results in the production of distiller’s grains and gluten feed — both of which are fed to livestock, helping produce high-quality meat products for distribution domestically and abroad. There is no shortage of corn. In 2004, U.S. farmers produced a record 11.8 billion bushel corn harvest — and some 1.3 billion bushels (about 11 percent) were used in ethanol production. Additionally, the 2005 crop was among the largest on record. 2007 will yield the largest corn crop since the 1940s. In other words, there is still room to significantly grow the ethanol market without limiting the availability of corn. Steadily increasing corn yields and the improved ability of other nations to grow corn also make it clear that ethanol production can continue to grow without affecting the food supply.
Links:
Popular Hot Rodding has a good read on E85 conversions. Mostly for older carbureted vehicle but still good info on carbs, pumps, ect.
From Honda Tech.
http://honda-tech.com/showthread.php?t=1812349