What is E85?
E85 is a fuel mixture that typically contains 85% or higher (160-plus proof) denatured ethanol and 15% gasoline. Ethanol (also known as ethyl alcohol or grain alcohol) is the "alcohol" found in alcoholic beverages. "Denatured" means that it has been made toxic or undrinkable, often by adding a small percentage of methanol. This minimizes the drug value of the alcohol, and also exempts it from beverage alcohol taxes.
In the United States, ethanol is derived mainly from corn. There are about 1,600 gas stations in America selling E85 fuel. Most of them are located in the Midwest, where corn is a staple crop.
 E85 vs. gasoline
E85 can provide horsepower that is comparable to gasoline. Its octane rating is about 100 to 105. This means that it can be used in higher-compression engines, which could lower emissions (confirm and expand this). However, E85 gets about 25% fewer miles per gallon than regular gasoline, and it contains less energy per volume than gasoline. On a few dyno tests, some people have found that a properly tuned turbo or supercharged engine can be made to produce a bit more power than than the same engine setup for premium gasoline. Fuel consumption is higher though. The main attraction for such engine use is that E85 can be had for around a quarter of the price of "racing gas" while having close to the same octane rating and performance potential. E85 isn't actually "better" than racing gas but sure can be a lot more economical.
 Benefits of E85
- As a "renewable" energy source, E85 has the potential to offer decreased reliance on foreign energy. As it develops further, it may also be able to demonstrate decreased carbon emissions when compared to standard gasoline.
- According to the US Department of Energy, ethanol has a "positive energy return". This means that it produces more energy than it consumes in its manufacturing process. The same is not true of gasoline.
 Damage caused by using E85 in an engine not designed to use it
- Prolonged exposure to ethanol corrodes many metal and rubber parts that are designed to be used with gasoline.
- Use of fuel with more than 10% ethanol content will void most car manufacturers' warranties.
- Water contamination of fuel is exacerbated by the presence of ethanol. Ethanol readily absorbs water but too much water contamination will cause excessively lean fuel mixtures.
- Air-fuel mixture problems. To achieve a usable fuel mixture, a lot more E85 is required. A carbureted car running E85 will need MUCH larger fuel jets than one running gasoline. Trying to run E85 with a carburetor designed and tuned for gasoline use will result in a very lean fuel mixture and a big drop in power. EFI cars will have similar problems. "Flex fuel" cars designed to run varying mixtures from straight gasoline to straight E85 have a fuel sensor in the tank line that can sense the proportion of alcohol content of the fuel. Thus the engine computer can adjust timing and fuel mixtures accordingly. Obviously other vehicles do not have any such capability unless heavily modified.
 Economic concerns from E85 use
- Ethanol production will increase the cost of corn, and the cost of food products that contain corn, or rely on corn for their production (such as beef). There is some concern that this is already happening.
- Ethanol production consumes large amounts of water.
- The cost of "converting" existing vehicles to run on E85.
- E85 may be viable, but it has a long way to go before it can be relied on by an entire economy.
- There is some concern that this is propaganda released from the American Petroleum Institute to tarnish and lessen alternative ethanol usage. The purchasing of corn futures by oil companies at high prices, driving up the cost of corn for billions of dollars, and selling it to companies such as General Mills cheaply recently caused the spike in corn prices. This was unrelated to ethanol production and corn now is down tremendously because big oil has stopped the artificial manipulation of corn futures to a certain extent.
 Performance disadvantages of E85
- Longer warm-up time.
- More difficult cold-starting in cold climates, especially below 25 degrees F.
- Ethanol has less energy or BTU's per gallon compared to gasoline. Flex-fuel vehicle owners report that gas mileage drops when using "straight" E85. Results can be as much as 30% lower than using just gasoline. Flex-fuel vehicles are a design compromise though. Vehicles built and optimized for strictly E85 uses get rather better mileage. Reports vary between 15 to 25% worse mileage than gasoline. Reports of the best results seem to come from owners of turbocharged vehicles.
 Aftermarket ethanol conversion kits
Largely for safety reasons, US law prohibits the manufacture of most ethanol conversion kits, unless they are EPA certified. The certification process is too expensive and time-consuming to be considered a reasonable option for most companies who might otherwise be interested in producing a consumer oriented conversion kit.
 Converting to E85
- Because it is slightly corrosive, some of the fuel system may need to be replaced. Ethanol, however, is much less corrosive than methanol, and the two should not be confused with each other. Many people have run their cars on E85 for several years with no fuel system corrosion problems.
- Ethanol runs at a richer air-fuel ratio, so you need to use more of it.
 Carbureted engines
- There are several carburetor companies now producing carburetors designed for the use of E85, like Quick Fuel Technologies and APD Carburetors.
- There are also companies that will convert your Holley style Carburetor to E85 as well, like Mark Sullens E85 Carburetors.com, e85carbs.com, and or Race on E85.com.
- All fuel and air passages must be modified.
- Many fuel pumps cannot pump E85 on an extended basis. Even the old diaphragm style pumps tend to suffer internal damage. Some seem able to hold up for years. There's no clear evidence of which ones last and which don't yet. Other than the electric racing pumps sold "for use with alcohol/methanol."
- Unprotected zinc and aluminum carburetors may corrode from extended use of E85.
 Fuel injected engines
Feedback type fuel injection systems are idea candidates for using E85. 50% larger fuel injectors are required, and an increase in ignition timing to compensate for the slower burning of the E85. The feedback narrow band O2 sensor is a Lambda O2 and does not need to know what stoichiometric is, the sensor looks for the most O2 in the exhaust and the engine controller makes all the appropriate fuel calculations for the new fuel. The larger fuel injectors and no engine controller modifications will prevent you from running dual fuel, as in gasoline or E85, or a mixture of the two.
Is this a better source for ethanol? Need to expand on this.
 Alcohol content
 External resources
 E85 conversion studies
- University of Texas at El Paso E85 Chevrolet Silverado Conversion
- University of Nebraska-Lincoln E85 Chevrolet Silverado Conversion
 Wikipedia articles
- Ethanol fuel
- E85 in the United States
- E85 in standard engines
- Ethanol fuel in Brazil
 Hotrodders forum threads