Earth Talk: Veggie Fuel Retraction
I wrote an article in the last Rising Firefly Magazine about the use of vegetable oil as an alternative to the use of petroleum-based diesel fuel. This is done with a two-tank fuel system. While the idea has been proven to work in certain applications, I am sorry to say that my experiment with it has been unsuccessful in my personal tests over a long-term period. When I made the modification on my car, I drove it problem-free for 15,000 miles on vegetable oil. It was during this period that I wrote the previous article championing its success. I feel that it is my responsibility to correct the statements I made in the last article in order to protect anyone from suffering the same financial loss as I did from using a two-tank vegetable oil system in combination with the car that I installed it on.
The car I chose to install the system on was a VolksWagen 2006 Jetta Diesel TDI. I did research on people who have converted this kind of engine (Direct Injection Diesel), and I found that there were examples of the system's success on the model of car I chose. There are some criteria that I made sure were stringently followed, such as, the use of quality waste oil from restaurants, the extremely thorough filtering and cleaning of the oil (above and beyond recommended standards), the appropriate start up and shut down regimens, and the regular changing of my grease filter in the engine compartment.
Even though I did all of this, at 16,000 miles of grease driving, my engine suffered irreparable damage/trauma when the rings and gaskets all went. The result was that I had to replace the entire engine. This was because the cost of replacing the rings and gaskets and re-tooling the cylinders combined with the labor charges, would have been more than actually purchasing a new engine.
The TDI (Turbo Direct Injection) engine on my car is built with extremely high tolerances, and deals with high pressures around 30,000 psi. (measurement of pressure meaning pounds per square inch). The older models of diesel engines have much lower tolerances and can take a varying level of fuel viscosity. The vegetable oil systems were originally designed for these older style engines, but have made their way into being installed on the newer ones, such as the TDI engine. The company that I ordered the system from even offers a kit specifically built for the TDI engine.
So the question is, why the huge failure in my installation? I carefully read through the testimonies of people who drove their TDI's on grease for 65,000 miles and up. The only difference that I saw was the type of driving that I was doing. I drive my car from New Jersey to Brooklyn New York several times per week. It is about a one-hour commute. The traffic and driving patterns are very hectic. I am an aggressive driver, and I put the pedal to the metal many times during my commute in order to merge, and to keep up with the fast traffic.
My conclusion is that while this system/car combination may work for some who drive less aggressively, the use of the system on a TDI under these high-pressure driving conditions can destroy your engine due to the viscosity difference between hot vegetable oil and cold type-2 diesel. In other words, the newer engines will not tolerate the lower viscosity of the vegetable oil during this type of high pressure driving over a long period of time because of the precision of the engine design. For example, on a 1984 Mercedes diesel, you would not have this problem because the engine is not as precisely engineered and is tougher, so the viscosity difference between the two types of fuel is negligible. I would suggest for anyone who is thinking of converting his or her car to a vegetable oil system, please do it on a pre-direct injection engine. This could potentially save you thousands of dollars. Do not make the same mistake I made. While the technology of driving your car on grease is sound on older models, its use on newer models is still debated heavily and should not be suggested to those who don't have money to blow on costly mistakes during their experiment.
Additionally, I stated that the diesel tank would only have to be filled a few times a year. This was also incorrect. I later found that I had to fill my diesel tank on average every 2,000 miles.
This technology is also inappropriate for people who only drive around town. It is really suited for those who drive long commutes. This is because the required distance of driving that is necessary to warm up the coolant before switching over to grease can be up to 10 miles, or approximately 20 minutes of driving. In the case of local driving of only a few miles per day, you would not really get a chance to drive using the grease in your car.
