Bought a '99 A4 Jetta w/ 250k miles a few weeks ago with Greasecar kit. Trying to do my homework on running WVO before I start putting together a system for processing the oil. I might have found a good fuel source; local pizzeria in town uses "Wesson Smart Choice - Cottonseed/Canola Oil Blend" (besides cottonseed and canola oil, ingredients include TBHQ and metyl silicone). I believe that Canola oil is pretty good for BD and WVO, what about cottonseed oil? I haven't read to much about that.
Much like Phil has stated, the most important aspects to your oil of choice is filtered properly and making sure it is dry.
For all extensive purposes, the differences within oils doesn't attribute to much when your heating it to lower viscosity. I haven't seen any study showing that X oil does better in a converted kit better than Y. Also, when your dealing with WVO, I'm not a scientist, but I'm fairly certain polymers and branched chains that make up the oil itself are broken down through excessive heating. Most oils break down at a certain temperature and most all fryers exceed that temperature, thus causing free fatty acids... (an even worse for your health, trans fats
) Cetane values, Iodine values, and measurements of viscosity are all changed at this point.
There is no scientific proof to this, but in our experience, highly used and burned WVO is less viscous than new oil or lightly used oil. It takes weeks for lightly used oil (FFA testing 6 and below) for the water to seperate out. Highly used oil in my experience has shown to be less viscous and for our purposes of achieving atomization and quality combustion is a very good thing. As far as acids within the IP and injectors themselves, this has yet to readly be determined. I believe there may be a correlation between highly acidic oil and premature wear on IP and injectors. (This is only a theory however and will probably remain that way). FWIW, I run blends of highly acidic and low acidic oil in my car and in my fathers powerstroke and 40k on his truck and almost 25k on my car has yielded no ill effects.
Its funny this topic was brought up because together my father and I have burned a couple varietys of oil (corn, canola and peanut). We noticed a huge increase in on tap power with peanut oil versus the other oils we have ran in the past. This was lightly used oil. It was literally a 10-20 HP noticeable "seat-of-pants" effect. This would lead me to believe that oil that hasn't had the beejesus used out of it might retain some of its chemical structure and makeup. More on tap power would lead me to believe that the peanut oil we used had a much higher cetane value (more readily able to combust) than any oil we tried running in the past. Higher cetane equals a more volitile combustion and more power. (Some people notice the same effects with fuel treatments such as dieselkleen).
By the way, if your car came converted with a kit... You might want to make sure your car is running the way it should and do a once over check with a trusted mechanic. As I've stated in my guide, if you start off with a well running, well maintaned car, your opportunities for a successful conversion increase in a big way.
Good Luck to you and Happy Greasing!
