Real-World Running on Biodiesel
Since we are neither buying nor selling biodiesel, the above legal restrictions don't apply to us, so we decided to do a bit of experimenting using our own vehicle, a '96 Dodge dualie powered by a 12-valve Cummins. At our first fill-up, we started with a 50/50 mix of biodiesel and petroleum diesel. For about the first few miles, we didn't notice any difference at all. The engine started and cruised just as if we had filled up at a regular fuel station. Then, something really pleasant started happening: The sweet smell of cooking oil began to emanate from the exhaust. No soot, no stink, just a mild aroma, faintly reminiscent of Asian food.
As for the noise pollution, Todd Smith of Socal Alternative Fuels has been running his Duramax-powered Chevy Silverado on straight biodiesel for several months, and we were frankly surprised by how quiet his engine sounds. But, on our Dodge Ram, the muffler had been removed by the previous owner, so that may be why we didn't notice any immediate change in engine noise, nor did we see any significant change in our fuel mileage.
After consuming this sample, we had to run a couple tanks of conventional diesel on a long road trip before we could fill up again on biodiesel. We encountered no difficulty switching back to pure petroleum fuel, but we were surprised that the scent of vegetable oil continued to linger for another tank or two. The next time we showed up at Socal Alternative Fuel with a nearly empty tank, so we were running on nearly 100 percent biodiesel-again, no problems and similar mileage results. This time, however, the engine noise seemed to be muffled slightly. A friend of ours with an '82 Chevy powered by a 6.2L GM diesel ran on straight biodiesel as well, and only noticed some slight surging and slow startup, but otherwise no difficulties.
 How do these systems operate?...  How do these systems operate? After collecting several gallons of waste oil (Asian restaurants are generally preferred by biodiesel refiners), you first need to filter it and evaluate its quality by titration, a simple chemical test that determines the amount of lye and methanol required. Then, these two chemicals are carefully mixed together in a sealed container and then added to a tank of lukewarm vegetable oil (heat speeds the conversion process). After about 30 minutes, glycerin separates out from the oil and is drained off, which can be resold to make soap or as plant fertilizer (or to make propylene glycol, a nontoxic antifreeze for cooling systems). |  Even though the resulting...  Even though the resulting biodiesel is slightly cloudy at this point, it can be burned as fuel, but the Fuel Meister adds another step of "water washing" for further refining. This step requires a mister built into the top of the oil tank, which sprays water into the oil. As the water sinks to the bottom (since oil floats on water), it captures impurities, and is later drained off. The Biodiesel Xtractor, however, is designed to eliminate this step by adding an oil filtration chemical called Magnesol (cost is about $1.50 a pound which breaks down to 11 cents per gallon), which the manufacturer says will remove any remaining contaminants. |  Lastly, the biodiesel is then...  Lastly, the biodiesel is then pumped through a water-separator to eliminate any remaining moisture and a 14-micron filter to get rid of particles and impurities. The final product is a clean, honey-colored fluid that can be poured directly into your vehicle's fuel tank. |
We should emphasize that these were short-term tests, and we can't comment on the long-term effects. Smith has been running his Silverado for several months now and reports no problems at all. With biodiesel's inherently higher lubricity, compared with conventional diesel, there are both pros and cons. The fuel pump and engine get more lubrication, but biodiesel is a solvent and tends to loosen accumulated sludge, which might clog the filter and require replacement after running a tank or two. Also, as with any chemical, biodiesel may damage painted surfaces, so spills require immediate cleaning. In addition, most pre-'94 vehicles and a few late-model cars may have rubber fuel lines and/or rubber seals in the fuel system. Biodiesel will gradually swell the rubber and degrade it. It's a good idea to check under your hood periodically and replace fuel lines and seals with a biodiesel-resistant synthetic, such as Viton, if they begin to degrade.
Cold Weather Use
For those who drive in a colder climate, biodiesel gels at around 32 degrees F or higher, depending on what kind of oils and fats it was made from. If you try to start your car at 10 degrees F, the biodiesel will probably be frozen in your fuel lines and the engine will not start. If you live in a colder climate, you may need to run a blend of biodiesel and diesel in your vehicle or modify your vehicle to heat your fuel system. Even with these drawbacks, the question arises that if the average Joe can make biodiesel at home, why aren't more fuel refiners doing so on a mass scale? It's certainly not a big technical hurdle, and we're already seeing a number of companies producing biodiesel. Interestingly, the feedstock vegetable oil could also be obtained from algae, jatropha, or jojoba beans, or other sources of non-edible vegetable oil that can be grown in, and harvested from, areas that don't normally produce food-grade agricultural products. We've also heard of new research that says it's possible to make biodiesel from chicken or turkey fat.
Whatever the source of the biodiesel, can you imagine how valuable a non-toxic, renewable fuel would be? The benefits are obvious: reducing our country's dependence on foreign oil, recycling waste products, lowering pollution levels, and even saving money for the consumer. The potential impact is mind-boggling. Forget about expensive, complicated fuel cells, electric cars, and hybrid powertrains. The solution is right under our nose, and it smells like cooking oil.
What Are the drawbacks?
Well, you need to locate a dependable supply of used fryer oil and be willing to siphon it into a portable tank, then transport and store it in a dedicated workspace (about half the size of a single-car garage). More importantly, you'll need to exercise some safety precautions (while wearing gloves, goggles, and apron) in working with the methanol and lye, because they become toxic when mixed together. And you'll also need to dispose of the glycerin byproduct. Even for those who view themselves chemically challenged and would rather purchase biodiesel from a supplier, this alternative fuel still makes a lot of sense, and it has been thoroughly tested and proven on the road.