CJ I just sat down and read this entire thread for the first time. Your information is very helpful and I appreciate how you've continually shared your experience. Please keep it up!
I have been running WVO mix in my '96 and '98 12-valve. The highest I have gone is almost 50%, but I need to work on refining my process, and doing better to ensure it is filtered good and 100% free of moisture content.
I am going to check into the isopropyl alcohol idea. The thought of putting alcohol in the fuel concerns me a bit, but if it helps the waxy hydrogenated content in some of the oil I have I'm willing to try it. Some of the oil I have is clear liquid above 60 degrees, but starts to cloud and solidify below that.
I have a fuel heater I plan to install on my '98. On my '96 I installed 1/2" ID fuel line all the way from the tank, which has helped fuel pressure considerably. When increasing the WVO percentage, the viscosity increases and makes it harder to draw through the stock line. The 1/2" line helped quite a bit, so I'll probably do the same mod to my '98.
After burning quite a bit of WVO in the '96 I pulled the head. No buildup on the pistons at all, they only had a light soot coating in the bowl and outer piston surfaces. That's despite the fact the '96 doesn't burn WVO nearly as well as my '98, probably because it has almost 400,000 miles on it (it stinks like cool combustion, whereas the '98 burns clean), so it's comforting to see this.
What kind of exhaust odor does your '04 have when fired up in the AM, and how does it smell at operating temp? When I have 50% WVO in the '96 it smells a bit like fryer oil, but at operating temp there is very little odor of any sort. Doesn't smell that much like a diesel, doesn't smell much like burning veggie oil either. . . hard to describe.
Vaughn