Biodiesel can really help smooth the racket, but a big reason for that is that it ignites at a different time than diesel. Probably you would want to advance your timing a little to keep your mpg up.

I've liked running bio the couple of times that I have, but it never smelled like hamburgers burning. I wonder from your description if he isn't selling some kind of purified vegoil... That's also a real good price for biodiesel, recently it usually ranges a little more expensive than pump diesel. If it is, run with it all summer!

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