BioDiesel or Veggie Oil?

June 26, 2006 4:22 PM

Vegetable Oil vs. BioDiesel?

I am about to purchase a diesel van and am thinking about converting it to bio-diesel/vegetable oil. I would like feedback from others as to how well their vehicles run, conversion costs and costs for ongoing maintainence and the pros/cons of both fuels.

posted by goalyeehah to technology (8 answers total)

I'd have to say that making it run on Biodiesel would be a much smarter choice right now. Biodiesel is in the brink of becoming a real Thing, and if you want something you can actually fill up at a regular retail station (assuming you live in a progressive area that has some), you should really go with the real stuff.
posted by floam at 4:29 PM on June 26, 2006 [1 favorite]

If you live somewhere where the temperature gets low enough (i.e. below freezing), both of them will solidify in the fuel tank if used pure, and then you can't use your vehicle. That's why most people use a mixture of no more than 30% biodiesel mixed with 70+% diesel from petroleum, because that won't solidify at low temperatures.
posted by Steven C. Den Beste at 4:34 PM on June 26, 2006

I live in Southern California so low temperatures would rarely be an issue.
posted by goalyeehah at 4:47 PM on June 26, 2006

I'm in the midst of building several biodiesel production facilities and have a few thoughts you may find helpful. Oil and biodiesel are not the same. A couple of key points:

1. Is your van new? If it is, you may want to check with the manufacturer on what blends of biodiesel they warranty and not exceed them. Usually manufacturers will warranty at least 10% and sometimes up to 20%.

2. If your van is new and you want to use 100% biodiesel and you don't care that your vehicle will no longer be under warranty, then no "conversion" is necessary. You just put biodiesel in the tank and it should work fine.

3. If your van is used, you can put up to 100% biodiesel and run it; however you should be aware that biodiesel acts as a solvent and because over time diesel leaves sludge in the tank, the biodiesel will clean it out. All of this sludge will eventually get caught in your fuel filter and you will need to change it. Most people change their fuel filter every 3000 miles (I would do it twice) just be sure they catch most of the sludge.

4. Please note: for biodiesel, you will not need a conversion kit.

5. If you use veggie oil, you will need a conversion kit because you will need to prime your engine with diesel and then run it off the oil once the engine is warm. From my conversations with car manufacturers I personally would ONLY consider using veggie oil if the car is old. Modern diesel engines will get gummed up by veggie oil. The older diesels will run on almost anything and are difficult to break. Modern ones have very delicate fuel injectors which will quickly get clogged, and this will result in all kinds of problems.
posted by zia at 4:50 PM on June 26, 2006

If you are interested in the cutting edge of veggie oil kits and conversion, check out frybrid for more information. My brother and his friends (not affiliated with frybrid although they rave about them) have now converted several vehicles to burn veggie oil to much success including a 1986 bluebird school bus that they drove around the country being circus people.
posted by ilikecookies at 5:47 PM on June 26, 2006

On preview: Geez, sorry for the length! As you can tell this is something that I can type on forever about.

I have a 2001 VW Jetta TDI that has been converted to vegetable oil using an Elsbett single-tank kit. It has run for 2-1/2 years and about 16,000 miles on used soy oil without a fuel-related problem, with a little biodiesel thrown in occasionally (knock on wood.) The cost of the kit was about $1100, not including installation, and involved shipping the car's injectors to Germany to be modified, which took 2 - 3 weeks. I spent about another $300 on an oil filtration/pumping station setup (barrel, filters, pump, filler nozzle, etc.), but most people get by with less. Ongoing costs are filters for the pumping station (which works out to be about $0.10/gal), as well as changing the engine oil and fuel filter about twice as often.

Probably the biggest thing to consider is that some engines (their injection pumps, really) are not suitable for use with vegetable oil. You don't specify what kind of van you're thinking about buying -- the engine it comes with is going to have a big effect on your decision (or vice versa.) In general, newer "direct injection" engines, especially those with common rail fuel injection systems, are less tolerant of VO than older "indirect injection" engines. (My Jetta is a pre-common rail direct injection engine, so I'm sort of in the middle of this continuum.) If you're talking about buying a Dodge Sprinter of recent vintage, BD would be the way to go. If you're talking about buying a mid-'80s Chevy with a 6.2L engine, VO would probably work fine. (If you're looking at a Westfalia with a 1.6L Rabbit engine dropped in, I would suggest that you buy something -- ANYTHING -- else. Not because it won't run on VO -- it will -- but because, well, it's a Westfalia with a 1.6L diesel. If you're lucky you'll get from 0 to 60 in less than a fortnight.)

The decision for most people to use VO or BD I think depends on their comfort with being a guinea pig. BD has more of a comfort zone -- you don't have to convert your vehicle, there are distributors that have actual gas pumps, and some auto manufacturers are starting to sanction its use. On the other hand, there is zero infrastructure for VO, it involves serious mods to your vehicle, and it voids your warranty instantly. VO tends to attract the really hands-on car guys, groovy hippies, and the obsessively cheap (I'll let you guess which categories I fall into.) The bottom line is, VO (much more than BD) is experimental, and nobody really knows how successful it will be over the long term.

There are lots of online resources about VO-based biofuels. One of the most active is the Biodiesel Infopop board, which contrary to its name has both BD and VO sections. If you poke around there, you will see that this is a question that has been debated at great length, with fervor that borders on the religious.
posted by harkin banks at 6:53 PM on June 26, 2006

You might want to look at Grease Car. Their FAQ pushes most of the pros of a vegetable oil system and contradicts the low temperature as well as working with some newer diesels (in particular, they claim to be friendly with the VW TDI engines).
posted by plinth at 6:53 PM on June 26, 2006

More info on a previous thread.
posted by zonkout at 2:51 PM on June 27, 2006