How Does Fuel Consumption Work? Which Engine Is the Most Efficient?

To measure the efficiency of each engine, I connected each engine to a bearing that rotated one wheel. The number of these wheel rotations per fuel is the unit I used to compare the different engines.

For the electric engine, I rotated 30 wheels at the same time (so I didn't have to let the game run for 9 hours or so). I've converted those numbers by comparing the results to a gas engine at 30 wheels and how the gas engined scaled with one wheel. Since the total energy output of an engine is weight*speed, the results should be the same(after adjusting for weight), anyway.

For the thruster, I put it with a cardboard block onto a wheel. I've compared those results to a gas engine rotating the same thruster on a wheel. For the results of upgraded thrusters, I simply multiplied the results of the level 1 thruster by the upgraded fuel duration, as higher-level thrusters have less weight(which took me way too long to figure out.)
However, I don't know if this approach is an efficient way of harvesting the energy of the thruster, so there might be a considerable waste of efficiency due to my setup. If you know more about this, then please let me know in the comments. So take my numbers for the thruster with a grain of salt.

I measured the time that one fuel lasted in my editing software. I also counted the frames that the rotations of the wheel took and averaged those numbers to get pretty accurate results. I would assume a margin of error of 5% for my data(t also note the potential inefficiency of my thruster setup).

I measured the following data:

The factor accounts for multiple bearings and extra wheels.

The results for the thruster setup are the total rotations multiplied by a constant, which is the level 5 engine's result at 1 wheel divided by its result at the thruster setup. This should ensure comparability for the results of the thruster.

How weight scales with upgrades:

How time per fuel scales with upgrade:

And finally a comparison of all the engines at level 1 and 5:

1. Weight increases fuel consumption
   
2. Efficiency +1 increases time per fuel
   
3. Powering engines(not thrusters) continuously is more efficient
   
4. The electric engine and the gas engine are about equally efficient
   
5. Thrusters still suck
   
6. The number of bearings increases fuel consumption
   
7. Power level increases fuel consumption (if speed actually increases)
   
8. I hate clam diving

Thanks for reading the guide! Don't forget to like and favourite! Maybe watch the video if you haven't already. Feel free to discuss my results in the comments. I'll read each comment and will (try to) answer questions.

Somebody looked at the game code and came to the following conclusions:

1. Efficiency scales exactly as I assumed
2. Batteries and gasoline don't seem to have a difference, so the electric engine and gas engine should be equally efficient
3. Past a certain point, fuel consumption doesn't increase linearly with weight, but with a square root.

Source(See for more details) https://www.reddit.com/r/ScrapMechanic/comments/jcciqu/ive_used_science_to_determine_which_engine_is_the/g91tkll?utm_source=share&utm_medium=web2x&context=3