How to Boost Octane With Alcohol

Written by sean lancaster
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How to Boost Octane With Alcohol
Provide a boost to your automobile by adding alcohol to your gasoline. (Jupiterimages/ Images)

Gas stations sell fuel with different octane ratings. The octane number is a measure of the degree to which a fuel burns in a controlled manner rather than exploding in an uncontrolled manner. The octane number for a fuel is determined by testing in a laboratory with a well defined and characterised gasoline motor. The knock resistance of the fuel defines its octane rating. Knocking occurs when the fuel-air mixture in the cylinder of an engine is not uniform. The effects of knocking on an engine range from completely destructive to no effect. Higher octane ratings are therefore beneficial for engines.

Skill level:

Things you need

  • Ethanol
  • Volume measuring device

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  1. 1

    Check your owner's manual for its compatibility with alcohol fuels. Many newer model cars have engines that run efficiently on E85 fuel. The E85 contains 85 per cent alcohol per gallon with the balance made up of gasoline. The octane value of the E85 is higher than the octane number of normal gas but requires special precautions to prevent degradation of the gas tank, engine and fuel lines. Alcohols have a higher octane ratings than any grades of automobile gasoline. Vehicles that have the flex-fuel option are the best choices for using gasoline with alcohol added.

  2. 2

    Select the type of alcohol you will add to the gasoline to increase your fuel's octane rating. Primarily, the low chain hydrocarbon alcohols work best for adding to your gasoline. These include methanol, ethanol, isopropyl and butanol. All of these alcohols are corrosive to some degree on parts of the engine and fuel system. Methanol and ethanol are the most corrosive but also the best choices for economy. Your best choice is ethanol due to the lower price and wide availability of ethanol.

  3. 3

    Determine the percentage of alcohol you will add to your gasoline. To achieve the least damage to your vehicle the optimum per cent of alcohol added is 10 per cent. As you add alcohol to your fuel, water will collect in the gas tank due to the water that is contained in even the highest grades of ethanol. Periodically you will need to use a drying additive in your tank to get rid of the water.

  4. 4

    Add 340gr to each gallon of gasoline you put in the gas tank. This yields slightly less than 10 per cent ethanol per gallon. To find the increase in octane rating use the formula that follows: (gallons of gasoline X gasoline octane rating) + (gallons of alcohol X alcohol octane) / total volume of fuel = final octane rating. Assuming you use a premium grade gasoline with an octane rating of 92 and added 10 per cent methanol with an octane rating of 101, you would have a fuel with an octane rating of 94.7.

Tips and warnings

  • Work in a well ventilated area when dealing with fuels and fuel mixtures.
  • Wear protective equipment when handling both gasoline and alcohols.
  • Using alcohol in higher percentages than given may result in severe damage to your vehicle.

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