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      09-21-2010, 12:39 AM   #22
Mr. 5
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Drives: M3
Join Date: Apr 2007
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2007 e90 335i  [4.00]
Originally Posted by Ironring Racing View Post
Good first try, and a good exercise to go through the math, but as has been pointed out:

1. Power/"dyno graph" in each gear will be different, especially in this car with the gear specific OEM (and aftermarket) mapping
2. Doesn't take into account the rpm/power you enter the next gear at. By your calcs you should shift at 6k in 5th. Look at the low RPM that puts you in for 6th. Think of it as "power under the curve". You want to maximize both the exit gear shift rpm power, AND the RPM/Power that you enter the next gear at.

O-cha has it, acceleration (G-force) graphs for each gear are the best real world data. Maximize the acceleration forces across your shifts. i.e. you want to maximize the combined acceleration from both the gear you're leaving, and the gear you're entering. Could also be done with dyno graphs, but you'd need them for each gear, and you'd be optimizing for best overall power from the gear you're shifting out of, and the gear you're shifting into.
I just did some pulls on the way home from work and compared the Gs at redline to the Gs at the same speed in the next gear and it matches what I have said. The acceleration up to redline in 1st (for example) is greater than being in second at the same speed. In other words, if I would have shifted before redline, I would be losing acceleration.
I'll dive more into this and look at the power under the curve but I have a feeling that the results are going to be extremely similar.
e36 M3 Coupe, e36 325i Sedan
e90 335i--SOLD

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