I took college physics. I learned that power is unit work per unit time, which can be expressed as newton-meters per second. Torque is a cross-product quantifying rotational force accounting for a lever arm, which is expressed as newton-meters. I know that the distance in the measurement of torque is perpendicular to the direction of rotational motion whereas the distance in measuring power is parallel to the direction of motion, so these are not the same “meters” at all. But both of these involve a measure of force – more force means more power and it means more torque. However, when it comes to car engines, two engines can have the same horsepower but very different torque. Why do HP and torque not increase in lock-step? Is this just a matter of available gear ratios in the transmission? Or is there a way to build an engine deliberately to make torque vs. Deliberately to make horsepower independent of the transmission? Thanks!
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Torque = how much force can be applied. Related to how much fuel combusts at once.
Horsepower = how quickly that power can be applied over time. Related to how quickly the engine shaft spins – generally related to how many times per second combustion occurs (in eli5 terms)
Engines with large cylinders and slow rotating output shafts have a lot of torque, and require high gear ratios to spin wheels quickly
Engines with small cylinders and quickly rotating output shafts have low torque, and require low gear ratios to not spin wheels too quickly.
There are practical materials engineering limits for size of cylinder vs speed of rotation. Also in transmission gear wear vs power. And so we see the common related bands of torque vs horse power in modern cars.
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