hybridSS: you are falling into the same fallacy trap as tony:

peak acceleration only happens in WHATEVER gear has the highest POWER AT THAT SPEED. in first gear there is no lower gear so your acceleration peak will be at the torque peak in that gear. yes. i NEVER DISPUTED THAT.

i said that at ANY given speed (excepting the first gear scenario), your peak acceleration will be at peak HORSEPOWER.

trust me, i am not wrong.

peak acceleration at any given speed is where power is maximized. period. empirical rule. bar none, no arguments. if you disagree, i can prove why you are wrong.

in the case of first gear:
at the torque peak in first gear there is NO gear selection that will give you more power. go beyond that and your acceleration DOES slow, but that's only because there's still no example of a gear where you have more power than first gear.

tell me. which do you think will give you more acceleration at say 60mph?
200ft-lbs @ 1500rpm? or 125ft-lbs @ 10,000 rpm (from the SAME hypothetical engine, in the SAME car)

ill give you a hint:
pick the second one

i NEVER disputed the peak acceleration in a car overall would be at the torque peak in 1st gear. that' the ONLY time you will ge more acceleration from the torque peak than the power peak. in ALL OTHER GEARS if you drop a gear and make more power you WILL get more acceleration. period.

tony is ONLY right in the context of a car with a one-ratio transmission or if you only look at each gear independently.

i made 2 statements earlier (modified here to account for the 1st gear anomoly and to include both discrete ratio transmissions and CVTs).

• at any given speed peak acceleration occurs at whatever available gear ratio maximizes power.
• in any given gear, peak acceleration occurs at maximal torque.

both statements are 100% factually correct. dispute them all you want, if you choose to do so, you are wrong.

the reason why the first statement says at at any given speed (and i have been trying to emphasize this point but no one seems to get it). obviously as speed goes up, acceleration goes down and there are several reasons for this:

1: more air resistance
2: after gear change, less mechanical advantage
3: the power/work the engine does changes the kinetic energy

to further explain point 3:
kinetic energy = 1/2 * m * v^2. as your speed goes up it takes a smaller change in velocity to get the same change in kinetic energy (which is limited by engine horsepower and ultimately what the the engine does AFTER air resistance and rolling friction). less change in velocity in a given time span = less acceleration.