i have been hearing about some program on the computer to find out what you shift points should be. does anybody know of this?

 

You need to dyno your vehicle first since you need hp and torque data at specific RPMs. I'll be making a spreadsheet of some sort once I get a chance (or if anyone knows javascript they can help out).

 

i have several dyno sheets for my car. i knew i would need that, but i thought there was a program already out there. thanks

 

After dynoing, these are my calculated shift points as indicated by the tachometer:

1-2 6600
2-3 6300
3-4 6100
4-5 5800

These shift points have netted me my best ets. I'm still confused when people say you should leave a 4th gen in 3rd thru the 1/4 mile. It doesn't make any sense because the 4th gen makes absolutely no power after 6000rpms. If you hold onto 3rd, you're crossing the line at 6500 where the car is making about 130fwhp. If you shift to 4th, your crossing the line making 165fwhp.


Dave

 

DAVE B, i have an auto by the way

i know what you mean. i have dyno'd my car several times and i stop making power at 5550 rpms and then very little at the red line.

Now with that being said i did a highway run this weekend with ming in my car. i was having a problem getting above 125 mph. when the car shifted itself into 4th right before red line the rpm would drop back to 4000 rpms. then there was ZERO pull. it was like i was standing still.

well the i took o/d off and took 3rd past redline, slightly, then turned o/d on. well i pulled up a hill past 120 in 3rd. then on the back side of the hill i hit o/d on and almost hit 140 mph. it was about 137 mph.

so this is how i got to wondering about shift points. i always thought that shifting sooner than redline would keep me in the power band, but this proves in my case for my automatic that i need to ride 3rd longer.

anyway, i have heard from several people that there is a computer program or math formula for this and i wanted to see what it had to say.

 

shifts take up time

 

It took some digging but here is the program you can download and play with http://home.earthlink.net/~patglenn/. Its called cartest and once you input the power curve it will give you the optimal shift points.

 

I found this using google.com search:
http://www.rapidline.com/calc/chassis/pcshiftp.htm
dont konw how accurate it is but its worth a shot

 

this has always been my theory because its only reason that I can think of why I can't get anything close to my fastest times when I use 4th

 

I was always under the impression that once the car was over 70 or so and accelerating, it carried a lot more momentum therefore shift speeds didn't influence et near as much as the 1-2 or 2-3 shift. I can bang my 3-4 quicker than I can my 2-3 simply because it's just like grabbing the 1-2 (straight down).


Dave