The "Grease to Greece" race, the brainchild of 34-year-old Londoner Andy Pag, took the teams on a 10-day mission across Europe in which they begged oil to fuel their cars from restaurants, motorway cafes and fast-food joints along the way.
"There is no reason why Joe Public cannot do this, save themselves a bit of money and help the environment because they are not using fossil fuels," Pag said.
The race ended with a ceremony at the British Embassy in Athens where Ambassador Simon Gass presented a Golden Lard award to the team which had earned the most "Grease Marks" for collecting fuel.
Unlike expensive conventional rallies such as the Paris-Dakar, Pag paid only 500 British pounds for his second-hand Peugeot 405 and spent nothing on fuel since leaving London – saving the equivalent of what he paid for the car.
An experienced eco-traveller, Pag drove to the desert town of Timbuktu in Mali last year using a truck powered by waste chocolate. His next scheme is a round-the-world trip next year using aviation fuel made from recycled plastic bags.
Racers received a warm welcome from most restaurateurs.
"Whenever people have had oil they have been really, really willing to give it. It's a waste product for them so we are taking away their rubbish," said Pag.
Pag's red Peugeot was converted to run on cooking oil using a kit produced by Britain's Regenatec.
"Demand for this technology is rocketing," said Adrian Hensen, whose company sells bio-fuel equipment. "With petrol prices so high, lots of people are looking for ways to reduce their fuel bills and this is a fantastic way to do it."