- 1). Decide what ratio of of biodiesel to regular diesel you wish to use. B100 is the technical rating for a fuel that consists of only 100% biodiesel. While most vehicles will run this fuel just fine, over time, it will eat away the rubber components of your engine--such as the fuel lines and the rubber gaskets. B20 (20% biodiesel) is the highest concentration of biodiesel to traditional diesel that should be used in an unmodified engine. Lower concentrations than B20 are perfectly safe to use, and any higher ratio concentration can be used as long as the engine has been modified to run biodiesel.
- 2). Find the source of your biodiesel. This can be practically any vegetable oil or plant oil. Off-the-shelf cooking oils work just fine, but they will be much more expensive than regular diesel is in the first place. Simply filtering used frying oil is sufficient enough processing to pour it directly into your fuel tank. Talk with the manager or owner of a local restaurant, specifically one that serves fried foods such as french fries. You may actually be doing him a favor by offering to take their used oil off of their hands. Many restaurants have to pay a disposal fee each month for the trash company to haul it away.
- 3). Mix the two fuels together using your predetermined ratio. Large quantities of fuel can be mixed externally in 55 gallon drums, then transfered into the vehicle's fuel tank as needed. To mix the fuel on-the-fly, simply pour the measured biodiesel into the fuel tank, then fill it the rest of the way with regular diesel. For example, if you have a 20 gallon tank and it is 1/2 empty, you have roughly 10 gallons of unfilled space. If you want to use B20 (20% biodiesel), simply fill the tank with 2 gallons of biodiesel, then 8 gallons of regular fuel. Obviously you will have to take into account the fuel that was in your tank before, but as long as that was the same ratio of biodiesel that you are using now, things will not change.
The latter method is far from precise, and should only be used if you are willing to tolerate a fairly large margin of error. For the purpose of accuracy, it is always best to mix the fuel outside of the vehicle--this way, you get an accurate measurement every time.
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