You got that right . Been doing some reading but it all leads to BIO fuel or just flat out making moonshine .
You've heard of Ethanol? Ethanol is grain alcohol. What do you think moonshine is? Making your own fuel is the same thing as making moonshine. You have to distill the alcohol and use that to fuel the car.
If you ever see E85 it means that specific fuel is 85% Ethanol and 15% Gasoline. They "cut" it with Gasoline to denature it (so you can't drink it) and also to make it start easier when cold.
Most unleaded fuel available today is actually E10 - Meaning that it is 10% Ethanol and 90% Gasoline.
You can't do anything with cooking oil with a gas engine. The system simply isn't forgiving enough for it. Cooking oil needs a higher temperature and higher pressures to ignite the fuel than the gasoline engine can produce. You CAN however burn alcohol in a gas engine but there are a few things to remember:
1> Alcohol can eat up rubber parts and some untreated aluminum surfaces. It's important to make sure that all fuel system components are compatible otherwise you'll find that repairs can cost more than any potential savings.
2> While there are no laws (that I know of) against making your own fuel, if the vehicle is to be driven on public highways then you DO have to pay taxes on that fuel. Diesel for offroad use (heating, farm use, etc.) is actually dyed and truckers' fuels are often checked for the presence of this dye. If dye is found in their tanks that's proof that they haven't been paying the taxes on their fuel I'd imagine it would be easier to "get by with it" on gasoline vehicles but if you do get caught there are very stiff fines.
3> Fuel has to be aerated in order to properly burn. In other words the fuel vapor is what's flammable and not so much the liquid fuel itself. In order to get the most efficiency the amount of air has to be measured and the proper amount of fuel added. Most cars are calibrated to keep this air/fuel ratio at its stoichiometric ratio which for gasoline is 14.7 to 1 (14.7 parts of air for each part of fuel). E85 has a stoichiometric ratio of 9.8 to 1 which means that more fuel has to be added to the system for efficient operation. While modern cars have the ability to adjust this ratio based on what its sensors are measuring, most non Flex Fuel vehicles (vehicles that can run on any fuel between E0 and E85) cannot compensate enough to run well on straight E85 fuel.
I used to run a 50% blend on my old '95 Escort (Which would be about E40 or so) and it ran just fine but I've fixed the cars of many people who filled up with E85 because it was cheaper at the pump only to have it break down or run very poorly on them a mile down the road.
Another alternative might be CNG (Compressed Natural Gas)... although that you won't be able to make yourself.
