Maybe I haven't spent enough time looking at dyno graphs and trying to understand them, but can someone help me out here? I'm in a debate on another board, and I'm not wording my argument correctly. Let's say you've got your engine pretty well tuned (hypothetically). When looking at your dyno graph and trying to determine shift points, wouldn't you want to shift at the point where the slope of the tangent of the "horsepower" line goes from positive to negative? To try to maximize area under the curve? Or is it for a different reason? Can anyone help a brotha out? Thanks y0.

ive read in some other forums(exvitermini to be exact) you shift at your peak torque for best results.

i dont think it works like that. to determine your shift points you need to do dyno pulls in 2nd, 3rd and so on. where those graphs cross is your shift point:

what I would say (dont know how true this is) even if the HP is going on a downwards slope, if you shift higher, you can keep the lower RPMS on the next gear up (get what i am saying). You would need dyno sheets and a speed/gear ratio calculator to find out the best shift points. Lets say that at 5000 rpm you spike up to 150hp you peak at 190hp @ 8000 and drop to 155 hp at 9500 rpm (just making up numbers) when you go to the next year, you want to make it so that you have about 155 hp at the begging of the next gear so maybe you want to shift at 9300 rpm in second and end up at 5400 rpm in third (again just pulling #'s out of my ass). It is all about keeping the most area under the curve and having the begging and end up as much as possible. If your car had 1000 hp but only between 7000 and 7100 rpm, then drops back down to 100 hp, your still only going to run with a 5th gen civic si (again dramtizing)

yea, your paint skills explained it alot better then my mumbo jumbo talking crap. BTW, when i clicked on the thread, there was only the orginal post, when i was done talking, there was 6. I took to long to write.

you almost had it. but if you go all the way to redline, your hp will be lower than where the graphs cross. :edit: nevermind that, i see what your saying now

But i was just pulling #'s out of my ass, redline could be at 465465132132465465654654 rpm, I never said where it was

the FASTEST way to go is to shift at your peak horsepower, to fall on to your peak torque. gearing plays a major roll in this