The reason for using big engines that have high torque when we can use a smaller, low torque engine and use a transmission to get the torque needed?

Question

Smaller engines should have better fuel consumption so this should be better, right?

In: Engineering

Answer 1

Torque is only half of the equation when it comes to towing a lot of weight. The other half is weight, since that increases the traction that the wheels get. So having a big engine is a bit of an advantage in that regard.

That said: If you need a lot of weight anyway and you want to use as little fuel as possible, the best option is a diesel engine. That is for example why you never see a big semi truck using a gasoline engine.