How do I design car for MPGs in thrme teens and have some towing.)

[Eric.B]

There isn't a way to know the torque amount needed to increase fuel economy. As there are many other factors that come into play such as the aerodynamic drag of the vehicle, the weight, so on and so forth.

In 1902, you shouldn't be getting 32mpg. Vehicles today are 5 times more fuel efficient than they were in 1900.
10-20mpg are average in this time period. And that's for phaetons and other very light runabouts. Less for bigger vehicles.

For instance a Ford Model T Pickup Truck should get between 13-21mpg. In 1915...


Now, as to how to raise your fuel economy.
1) Light vehicle and components
2) Reduce frontal surface area and make it more wedgy.
3) If you have low HP/Torque, then the gearbox needs to be geared more toward torque than fuel economy. The vehicle has to be able to move.
4) If you have high HP/Torque, gear the gearbox to fuel economy.
5) Top speed matters as some of the calculations are at a cruising speed of 100kmh. If you're vehicle doesn't go that fast, it'll calculate cruising speed at full throttle.
6) Don't expect 2016 fuel economy numbers in 1900. It won't happen, nor should it.

I'm not in front of the game right now, when I get back I'll upload a save game with a 1900 vehicle with great fuel consumption numbers.