QUOTE(Duncan74 @ 22 Sep 2008, 05:49 )

I don't get the chip fat thing. So if we convert all our cars to run on chip fat, we save the planet. However we all die of heart attacks due to eating sufficient chips to prioduce 25million (cars) times 50 (litres fuel per car per week) = 1250million litres of chip fat per week. And I assume this extra frying is done via those frequently spotted solar powered chippies, or am I missing something?
LOL
Most of still gets dumped.
Up until the supermarkets got wise, it was cheaper to buy fresh veg oil than diesel - mostly because there is no duty - but now it's at least as expensive as diesel.
Not sure how well Saab/Fiat diesels cope with watered down, used oil (watered down with turpentine that is). These have longer hydrocarbon chains so you will probably get more coking (see elsewhere on saabscene for the problems this can cause and how to clean your EGR valve).
There are a growing number of retaillers selling FAME (veg oil where the hydrocarbon chains have been split with NaOH) but this will eat through any rubber seals in your fuel line.
C.