Re: The affects of Waste Vegetable oil on TDI\'s
... I think you shold also be willing to step back from your emotional investment and discuss both the pros and the cons of SVO objectively.
I wasn't attacking SVO. I was just pointing out that SVO does have known problems and that pretending that problems don't exist doesn't help anyone. Moreover, I provided links so that people could follow up if they so chose.
In particular, I took exception to the implication that anyone that has problems with SVO is to blame because they failed to use properly dewatered and filtered SVO. You can do everything right with SVO and still have issues, that's just the nature of the beast.
Dr. Stink, I think you and I agree on this, but we're coming from different sides of the fence. You CAN do everything right with SVO and still have issues. However, you can do everything right with diesel and still have the same issues (failed IP, coked injectors, etc.)
So, how do you determine what failure rates are normal, and what aren't? You do research. I haven't read every single one of the studies in the material you cite, but I have read many of them. Most of them are from the 1980s, when the need for preheated fuel wasn't quite as well understood as it is now. Additionally, most engines tested in those early studies had flat-topped pistons (no TDIs with their swirl-cup piston, rumored to be based on an Elsbett design.) For example, even the most recent study cited in the Jones and Peterson review (McDonnell et al. 2000) is unclear on whether or not the fuel was heated -- they chose to test a 25% VO blend because that was as much VO as they could use while maintaining a sufficiently low viscosity at -12C (that's 10F for those of you who are metrically-challenged.) In addition the oil they used was "partially degummed" -- the food-grade SVO/WVO that most people use have had those gums completely removed. That's sort of like saying engine won't run on diesel that's been chilled to -50F with a little bit of sticky stuff thrown in. Should we then conclude that it's impossible to run an engine on diesel, period?
My point is not that all of those studies are worthless -- I'm glad they were done. My point is rather that the research I have seen is not representative of how most people run VO in their TDIs. Until we get some, the jury is still out.
Now, I would LOVE to see some more current research, either lab engine tests or (preferably) real-world comparisons between cars running VO and diesel. But that costs money. Perhaps now that the current administration has made a public commitment to biofuels, funds will become available for testing these sorts of things.
You're saying SVO is experimental. I agree with you completely. You say problems happen with SVO. I agree, but with the caveat that nobody really knows how much more often these problems occur on VO vs. diesel. You say to drop the emotional investment in SVO and discuss its pros and cons rationally. I agree -- SO LONG AS those who have an emotional investment in deriding SVO do the same.
I don't like it when SVO promoters act as if the issue is closed, and that VO is proven safe. But I take exception also to the implication that anyone that has problems with SVO is to blame simply because they used SVO.
There are plenty of anecdotes on both sides, but precious little appropriate data. Until we get some, can we discuss this like rational adults?