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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It’s because power has the time element to it. You take two engines that make the same torque, and one can produce that torque at double the RPM you are effectively applying that force twice as often in any given time period, hence more power.
Torque does not take time or rate into consideration, it is purely a force applied. No matter how quickly or how slowly you apply it the torque is the same. It’s also why the old school phrase “HP sells cars but torque wins races” is bullshit. The extreme example of that is if I put a 3 foot breaker bar on a crankshaft I can pretty easily put 600 Nm of torque through the crank but I’m still only making like 0.5 kW of power at most.
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