[Bongle]

Keep in mind that torque is only one part of the motor-power equation. If you're talking about torque, maximum RPM is important as well in order to determine an approximation of how much horsepower you have. Since motorcycle engines typically have very high redlines, it means that so long as you keep them revved quite high, it'll feel like they have lots of power.

Think of a bar attached to the flywheel of your engine that is 1 foot long. At full throttle, your engine will produce a force of 18lbs at the end of that bar. At a given RPM, the end of the bar will travel a given distance per second. We know that Work = Force * Distance. The force in that equation is your torque value, and the distance is proportional to your engine's current RPM. The work value will be an upper-bound on your engine's horsepower at that RPM. This is why the horsepower chart on dyno graphs usually climbs fairly steadily as RPMs climb, because torque is usually pretty flat and torque essentially describes the slope of the horsepower graph.

In layman's terms:
-A high-torque engine like an electric motor feels spirited because at low speeds, it feels like it is generating more power than it 'should' at that RPM. Diesels also have very high torque.
-A low-torque engine (F1 engine, most motorcycle engines) requires your to rev it quite high in order to get the same amount of power as a high-torque engine. If it has a high enough redline (19000rpm-ish for an F1 engine), it can generate just as much power as a more torque-ey engine and motivate your car just as fast, but around town it might feel a bit strained.

Another interesting tidbit:
The reason that most engines have their torque and horsepower approximately equal is a coincidence because most engines have their redlines around 6000rpm, which is when they just happen to be equal when you're talking about hp and ft-lbs. You can actually get a decent idea of how high a gas or diesel-powered car's redline is by its horsepower and torque numbers: if the hp value is much higher than the torque value, it is almost certainly a very high-revving engine (F1: 200ft-lbs, 800hp, 19000rpm). If the torque is much higher, then it is likely a low-revving diesel.


As for the actual thread's question, maybe you could get an approximation by doing off-throttle glides on a flat road at varying speeds. If aerodynamic resistance grows as a square of velocity but rolling resistance grows linearly, then you could probably solve for a rough approximation.