That is the question. Either way you must have clean and dry WVO to start with. The question is where to do the work. Do you brew the WVO with chemicals to create Bio-diesel that runs in your un-modified vehicle? Do you blend the WVO with un-leaded gas and other thinners to run in your un-modified vehicle? OR do you modify your vehicle to run on straight WVO?

Brewing Bio-diesel
From my on-line research, brewing bio-diesel did not appear to be the best solution for a city dweller with limited experience. Storing and dealing with caustic chemicals was the biggest negative for me. The initial start up cost of the fuel preparation is a bit higher as well, but likely off set by the elimination of the need to modify your vehicle. My understanding is that many of the chemicals used can be recovered in your post processing and you have a bit of a closed loop. I could see this being the right choice if i was running a fleet of diverse vehicles so as to eliminate the need for diverse vehicle modification. On the plus side I understand that one of the by-products of this process is soap. Free soap.

Blending WVO
There is a fair bit of activity around blending WVO with regular unleaded gasoline (RUG) and isopropyl alcohol (IPA) in a 80/15/5 blend which closely mirrors the viscosity and cetane rating of diesel (D2). Other thinners include stale aviation fuel, turpentine, acetone and kerosene to varying mixtures. Some of the online posts i have read suggest that mixtures of up to 30% non-WVO thinners are possible without negative impact to a diesel engine. I am not sure the neighbors would appreciate my storing barrels of RUG in my garage. The volatile nature of these liquids and the need to dilute my free WVO with up to 30% of costly substances deterred me from pursuing WVO blending.

Straight WVO
This seemed to be the purist solution. I also liked that as a system completely parallel to the existing fuel system in my vehicle, worst case i can not turn it on, purchase bio-diesel at the pump and be no worse off. Other than some barrels, valves and filters, the harshest mechanism i will employ is heat in some of my WVO preparation steps. I will also make sure to use a well trusted and field tested solution for the modifications to my vehicle.

Decision made, time to see what the best vehicle and modifications are out there!

WVO