Hi ALL, On this forum, I found some really sensible answers to a few of my queries... posting one thats unanswered.. I want to understand how an engine or any power plant for that matter behaves under load... So i'm using a simple scenario to frame my questions... the values while made up reflect how an engine performs ... A typical engine accelerates from idling to ~6000 rpm in about 4 secs (a = ~1300rpm/s), the driver disengages the clutch to shift gears and the rpm drops to 4500. The driver engages the clutch and now the engine takes 3 secs to go from 4500rpm back to 6000rpm (a = 500 rpm/s). For going into the next gear rpm drops to 4.5K again and takes 6 secs this time around to reach back to 6K (a = 250rpm/s). The driver here is not throttling the engine at all except while changing gears...assume WOT operation throughout. If the car is in neutral and the driver floors the pedal he/she will probably get an engine acceleration of over 3000rpm/s. 1) What is impacting the engine acceleration? I have more questions... but i'll wait for an answer to this one first.. Assume no aero drag and rolling resistance and no losses in the transmission. Thanks!