Even I still have Citroen that I have managed to run with rather fuel efficiently, I have had no use for car for quite some time, so no need for fueling either.
For this summer I bought last autumn something bit older, 1981 Volvo 343 variomatic with 1.4l engine.
This will be true challenge to get going with small amount of fuel as there are some limiting factors.
Car has continuously variating transmission, that is no gears, just forward and backwards, goes as fast to both directions, total drive reduction varies from 14.5:1 to 4:1 without any steps. That 4:1 causes of course revs to be rather high as tire size of thing is 155/80/13.
Engine is 1.4l Renault based very basic motor, it has carburettor with one barrel only.
Aerodynamics then, well, it is 3dr model (hatchback) which is better than sedan, but it is not the most aerodynamic one, I believe cd is around 0.36, with frontal area of around 1.95 square meters.
Car is kind of classic, so not much of modding possible, mainly those invisible mods that are removable and no need to drill new holes or anything like that.
I bought it with broken 'transmission' it could not go much faster than 60kph and engine was screaming like being killed at that speed, but I fixed electromagnetic vacuum valve that controls transmission ratios and now it goes rather well.
Still some servicing left to do.
Car has only 133 341 original kilometers driven with good servicing, but after gearing trouble it stood years.
Typically people average around 10l/100km with these, I'm not sure what kind of target I should set as hilly ground is increasing fuel consumption a lot with these so not quite sure if I can get 40% off from that, I doubt it, anything more than 20% less than typical consumption is very good, I believe.
Just realized that I have no single good photo from the car, only pics that show some details of it, but here is rear section that is most important for aerodynamics:
I did quickly browse photo folders and two rather poor pics were found:
At least for people in United States this car might not be very known of as it was never sold there.
It can turn around on a dime and is very easy to work with, also parts are very cheap and insurance costs less than 100 euros for a full year, so with no need to drive a lot it is rather cheap to run despite bit high fuel consumption.
Also it is kind of nice challenge to try to get low consumption on this car, very big challenge
