Quote:
Originally Posted by Alex
Maximizing instantaneous thrust (by having the absolutely shortest gearing), isn't the same as maximizing thrust during acceleration (the shortest gearing possible taking into account how much the thrust changes above and below the peak, and taking into account shifting speed) - you want the maximum area under the curve.
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Yes, that's correct. Comparing and graphing instantaneous thrust is the key, rather than looking at average-thrust over time-period you're in that gear. As mentioned before, you have to account for the time required to shift. And that extra shift may negate the improvement in acceleration depending upon the distance you're covering. Would be interesting to do that graph for Ninjette compared to Ducati. With its higher revving engine and lower-torque, we may see that it's faster to redline every gear instead of shifting earlier.
Similar to this graph I made 30-yrs ago when I was drag-racing. This was obtained with an accelerometer, so it accounts for tyre-slippage in low gears as well as aerodynamic drag in higher gears.
In this case, due to spread of gears in car, it's best to redline each gear to take advantage of higher torque-multiplication (and linear-thrust at contact patch), rather than to shift right after torque-peak. Until 4th-gear where acceleration would be faster in 5th @ 125mph. This was important data as I was hitting just around 120-122mph at end of 1/4-mile, so shifting to 5th would be faster. However, it has to be balanced with loss of time doing the shift itself. If I had more power to hit 130mph, it would probably be faster to go with taller-gearing to avoid having to shift to 5th and losing that 0.3s from shifting.
BTW - integrating graph with respect to time & distance gets you area-under-curve. which is HP at wheels on ground. Interesting thing is while torque & thrust changes with gearing, HP at wheels does not. That's because HP is force/thrust per unit time per unit distance. So higher torque (1st-gear) in less time & distance is same HP at wheels as lower-torque (2nd-gear) over longer time-period and longer distance. All those "calculators" that estimate 1/4-mile times based on just peak-HP is way, way off.