I notice you are in Germany. Are you getting 15-18 miles per Imperial gallon, or 15-18 miles per US gallon ??? They are different.
>>>I notice you are in Germany. Are you getting 15-18 miles per Imperial gallon, or 15-18 miles per US gallon ??? They are different. >>> Yes they are. I think that would be about 6-8 km/liter if it was a 5.4 liter from an Imperial.
Per US Gallon, I converted online from Liter/ 100km to mpg. For example, 55 chevy with 235 and 3speed OD consumes a minimum of 10 liters per 100km and a maximum of 15,8l/ 100km which converts to about 23.5 mpg and 14.9 mpg.
We don´t have a lot of stop lights , stop signs and stop and go traffic here in my area, intersections have mostly roundabouts, so we seldomly have to do a full stop . I think to keep moving helps a lot in saving energy. Going from stoplight to stoplight in a big city will certainly give me differant results.