B20 Vtec power.

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If both engines are at the same speed, and both have equal acceleration and hence equal force, then both engines are producing the same amount of power. The more "powerful" engine is however using less throttle to keep the engine spinning at the same speed as the weaker engine.

Both are at the same speed and thus have equal piston accelerations. One engine has 10% more torque than the other and neither has angular acceleration - of course they're not producing the same power.

Both engines can effectively be thought to be at full throttle - the speeds of both engines are mediated by the choice of load (10% larger to counter 10% more power).