How do you guys set your WOT shift points?
11-01-2005, 11:37 AM
#1
How do you guys set your WOT shift points? I know the best way to set your WOT shift points is to log at the drag strip and adjust it there.
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on?
Do different stalls have an affect on shift points?
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter?
I get them pretty close for the people I tune, but just wondering if I can get them better.
How do you guys get them "right"?
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on?
Do different stalls have an affect on shift points?
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter?
I get them pretty close for the people I tune, but just wondering if I can get them better.
How do you guys get them "right"?
11-01-2005, 11:53 AM
#2
Originally Posted by Billiumss
I know the best way to set your WOT shift points is to log at the drag strip and adjust it there.
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on? Neither have to be dead on...i set the 1-2 by speed rather then rpm & the 2-3 by rpm rather then speed but if a tranny needs the rpms at 5800 to completely shift at 6400 thats what it needs...it happens sometimes.
Do different stalls have an affect on shift points? Yes
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter? Tranny slippage and the computer can only compute things so fast
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on? Neither have to be dead on...i set the 1-2 by speed rather then rpm & the 2-3 by rpm rather then speed but if a tranny needs the rpms at 5800 to completely shift at 6400 thats what it needs...it happens sometimes.
Do different stalls have an affect on shift points? Yes
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter? Tranny slippage and the computer can only compute things so fast
11-01-2005, 11:58 AM
#3
Answers/Comments in bold 
I know the best way to set your WOT shift points is to log at the drag strip and adjust it there.
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on?
It won't matter as the ECM will shift after the second setting is reached. So if you have a 3000 RPM and 90 MPH in 2nd (for example) shift point, then it will shift at 90 MPH. If you have a 6500 RPM and 20 MPH in 2nd shift point, then it will shift at 6500 RPMs. Ideally you want the RPMs and MPH to match or be very close for every shift point.
Do different stalls have an affect on shift points?
Yes, you need to log the Input shaft RPMs vs. the Output shaft RPMs to figure out the % loss. This can then be applied to your shift settings, and can be usefull if you are tagging the limiter. Most aftermarket stalls will have higher % loss than an OE converter, which means if you set the shift point at 6600, you may see upto 7000 RPMs prior to the actual shift.
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter?
The % loss of the converter was not taken into consideration for the required shift settings. 300 RPMs is not enought for some aftermarket high stall converters with decent STR (2.0+) or there is pressure loss at WOT. The Force Motor Table needs to be verified.
I get them pretty close for the people I tune, but just wondering if I can get them better.
How do you guys get them "right"?
I use the peak power and peak torque from a dyno run as my basis, then I double check the settings at the track (both shift points and pressure), only paying attention to MPH. As the ET is more traction derived and MPH is a more true showing of power-to-the-ground. After which I adjust the part throttle settings to suite the driver.
I know the best way to set your WOT shift points is to log at the drag strip and adjust it there.
But let's say you have your rev limiter set to 6,600 RPMs, you make peak power at 6200 and you have 3.23 gears.
What is more important, MPH or RPMs to be dead on?
It won't matter as the ECM will shift after the second setting is reached. So if you have a 3000 RPM and 90 MPH in 2nd (for example) shift point, then it will shift at 90 MPH. If you have a 6500 RPM and 20 MPH in 2nd shift point, then it will shift at 6500 RPMs. Ideally you want the RPMs and MPH to match or be very close for every shift point.
Do different stalls have an affect on shift points?
Yes, you need to log the Input shaft RPMs vs. the Output shaft RPMs to figure out the % loss. This can then be applied to your shift settings, and can be usefull if you are tagging the limiter. Most aftermarket stalls will have higher % loss than an OE converter, which means if you set the shift point at 6600, you may see upto 7000 RPMs prior to the actual shift.
Also, what is set wrong when you tap the rev limiter when it is trying to shift to the next gear and your RPM setting is 300 rpms lower than your rev limiter?
The % loss of the converter was not taken into consideration for the required shift settings. 300 RPMs is not enought for some aftermarket high stall converters with decent STR (2.0+) or there is pressure loss at WOT. The Force Motor Table needs to be verified.
I get them pretty close for the people I tune, but just wondering if I can get them better.
How do you guys get them "right"?
I use the peak power and peak torque from a dyno run as my basis, then I double check the settings at the track (both shift points and pressure), only paying attention to MPH. As the ET is more traction derived and MPH is a more true showing of power-to-the-ground. After which I adjust the part throttle settings to suite the driver.
11-01-2005, 12:01 PM
#4
I do it on the dyno while logging. Just start the pull in 1st gear and let it shift during the pull. They will never be exactly repeatable as they will vary slightly as the fluid temps change. I usually keep the rpm settings stock and up the mph settings until I get the car shifting where I want leaving a 100~150 rpm cushon between where it shifts and the rev limiter. If you can get ahold of a Hypertech manual, they have tables that show how many rpm each 1 mph effects the rpm shift point for each shift and for different rear gear ratios. While not exact especially with aftermarker converters, they give you a good estimate of how many rpms each 1 mph change makes.
11-01-2005, 12:55 PM
#5
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I don't think it matters whether you use RPM or
MPH to set the final result. It might be a little
easier to set RPM low and just mess the MPH around
because you have to do it on that basis for the part
throttle stuff anyway.
MPH to set the final result. It might be a little
easier to set RPM low and just mess the MPH around
because you have to do it on that basis for the part
throttle stuff anyway.
11-01-2005, 04:13 PM
#6
if you wanna see how to match your shiftpoints to your powerband, read these two:
http://redhardsupra.blogspot.com/200...ft-points.html
http://redhardsupra.blogspot.com/200...iftpoints.html
shift points, tire size, gearing, powerband, and size/type of converter are all co-dependent, that's why i like to use my spreadsheet to play with options, to see what changes cause what effects. play with it and you'll see what makes changes that are worthwhile, and which are just money spent without a real benefit.
http://redhardsupra.blogspot.com/200...ft-points.html
http://redhardsupra.blogspot.com/200...iftpoints.html
shift points, tire size, gearing, powerband, and size/type of converter are all co-dependent, that's why i like to use my spreadsheet to play with options, to see what changes cause what effects. play with it and you'll see what makes changes that are worthwhile, and which are just money spent without a real benefit.
you get the car running yet?? 