Lucas Tekkan

So yeah i’m no engineer, I would like to ask someone who knows about fuel consumption, because this is one of those life misterys that i don’t have the answer. I really like this car, I remember when I was a kid I saw one in France ( That was in the 2000’s). Always liked the looks and the rims, I know that the engine is kinda “Compact” but i would like to know how did they managed to get a V6 consumption in a V12