Originally Posted by semtex

If you went up through the gears I think you'd just end up with a separate chart for each gear. Because think about a dyno chart. On the x-axis it has the rpm scale. So you go through 1st gear and there's one graph showing your hp from 2k - 7500 rpm. You shift into 2nd and there's another graph showing hp from 2k - 7500 rpm. And so on and so on. On a 6MT, you'd end up with 6 dyno sheets. 7 for those with the 7AT. As for why they choose the gear with 1:1, I don't think it's so much that it gives you the best numbers, but more that it gives you the most accurate numbers, seeing how engine and transmission speed are in synch with one another.

Originally Posted by semtex

Actually, giving it a little more thought, if you ran through the gears, it look more like 1st gear: 2k - 7500rpm, 2nd gear: 4500 - 7500 rpm, and so on. Because it's not like your rpm is going to drop all the way down to 2k when you shift from one gear to the next at redline. Heck, depending on how quickly you shifted, it might only drop to, say, 5500 rpm.