Engines · Fundamentals · Demo
Torque is how hard the engine twists; power is how fast it can keep twisting — one is the other × rpm.
The torque curve is the input; the power curve is pure arithmetic: kW = N·m × rpm ÷ 9 549. Slide the peak down for a tractor, up for a superbike — and watch where peak power lands each time.
The torque curve here is shaped by the sliders; the power curve is never drawn — it is computed point-by-point from P = T × ω. That is all a dyno chart is. Peak power sits above peak torque because just past the torque peak, revs are still rising faster than torque falls.
In plain terms
Every dyno chart shows two curves, and they are not independent: power is just torque multiplied by engine speed (kW = N·m × rpm ÷ 9 549). That one identity explains the whole chart. Torque peaks where the engine breathes best; power keeps climbing past it, because revs are still rising faster than torque is falling — until they aren’t, and that’s peak power. What you feel in the seat is torque at the wheels; what wins the drag race is power, because gearing can trade one for the other.
P = T × ω. Nothing about an engine decides its power curve separately from its torque curve — measure one and the other is arithmetic. Peak power always sits at higher rpm than peak torque: after the torque peak, torque falls slowly at first while revs keep climbing, so their product keeps growing a while longer.
A gearbox multiplies torque by its ratio while dividing speed — power passes through unchanged. That is why power, not torque, sets ultimate acceleration: whatever the engine’s torque, a gear can be chosen to multiply it, as long as there is power behind it. “Torque wins races” is folklore; power at the wheels, held near its peak by gearing, is the physics.
A truck diesel makes its torque mountain at 1 400 rpm and is done revving by 3 000 — relaxed, tractable, unburstable. A superbike engine makes modest torque but spins to 15 000, stacking rpm into enormous power. Same identity, opposite bets: the demo lets you slide one engine between those two personalities.