dude, denis is correct, 4 L/100 km is 58 mpg... what are you smokin'?? Aveosam is right about you...
the metric fuel economy numbers are inverted i.e. volume per distance, instead of distance per volume.
So you have to take you 235 mpg and divide by 4, which gives you your 58.
I thought about cluttering this thread with a "pwned" or "fail" picture but then ya might be a bit sensitive to cluttery pictures taking up thread space! jfwy