I like the idea of a veggie conversion also, except shelling out 15 large
to do the basic conversion.  If gas goes to 5 bucks a gallon, waste veggie
oil prices will skyrocket.  There isn't enough to go around.
   We live in the real world, not a fantasy world.  In the real world, TD or
TDI conversions are so expensive, few (including me) can afford one. In the
real world waste veggie oil isn't thrown away in enough quantity to replace
1% of our requirements to run the vehicles in the US. Maybe we should all
band together and subsist off MickD's french fries to increase the supply of
veggie oil so we can all drive cheaper!
   In the real world, my 87 Westy, as currently configured,  gets 26 real
mpg at 65-70 mph, less going faster. My 91 GL automatic, went from 19-20.5
with the same changes. A couple of recent customers who received the same
package reported mileage better than I expected, for their vehicles as
configured.
   I was pretty happy at 24 mpg.  I am extremely happy at 26.  When I
travel, I normally have at least a kayak or two on the roof, so mpg will
suffer. I have enough instrumentation in my shop now, to position the stuff
on top to maximize the mileage.
   Once again, I say come give it a drive.  I will pay for the gas.

   John