4l80e WOT shift strategies 0411 pcm & HPT
09-17-2017, 08:18 PM
#1
4l80e WOT shift strategies 0411 pcm & HPT hey guys i'm having trouble getting consistent WOT shifts from my 4.8-4l80e-78/75 combo at the track.
it has two parameters one is shift by speed and one is shift by rpm.
so I do the math and see what speed i'd be if it was hooked and try and unify the tables. sometimes it'll shift at my intended rpm and speed. sometimes high, sometimes low. no codes and otherwise the transmission appears to function well.
another forum member who help me with HPT mentioned he thinks I can zero my speed tables and just shift by rpm which sounds like the perfect fix (especially since i'm having lots of traction problems)
what say ye?
it has two parameters one is shift by speed and one is shift by rpm.
so I do the math and see what speed i'd be if it was hooked and try and unify the tables. sometimes it'll shift at my intended rpm and speed. sometimes high, sometimes low. no codes and otherwise the transmission appears to function well.
another forum member who help me with HPT mentioned he thinks I can zero my speed tables and just shift by rpm which sounds like the perfect fix (especially since i'm having lots of traction problems)
what say ye?
09-17-2017, 11:45 PM
#4
yea blue cats tool works great. sometimes its best to set speed lower so it sees speed first thin makes the shift by rpm.
THis seems to work pretty well for me. Have u logged shift speeds and checked to see if maybe its just lagging a lil bit? I know the 80e shift way better than the 60e do going into 3rd but they do still have a bit of a delay.
THis seems to work pretty well for me. Have u logged shift speeds and checked to see if maybe its just lagging a lil bit? I know the 80e shift way better than the 60e do going into 3rd but they do still have a bit of a delay.
09-18-2017, 06:01 AM
#5
yeah I have logged shift speeds and they seem reasonable. i tightened them up a by 20% right off the bat back when I first put the tune together.
mostly its a first to second thing. if it hangs there, it short shifts 2-3
but if it's good there, its usually good on 2-3
mostly its a first to second thing. if it hangs there, it short shifts 2-3
but if it's good there, its usually good on 2-3
09-18-2017, 09:19 PM
#6
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what i do is zero out the shift times. All it does is modulate line pressure to try and achieve that shift time, aka slip the clutches.... Just let it shift it can take it. with a stall i like to use mph as the determining shift point as well.
set up a pid in your scanner to monitor shift solenoids then monitor you input speed sensor and make a pid using the input speed and putput speed to calculate your gear ratio input/output. You can then see how long it takes for the shift to occur and dial it in. Its very useful to see when the solenoid is active. Be aware with a 4l80e segment swap the shift solenoid id's will be reversed in the scanner as it still thinks its a 60e.
set up a pid in your scanner to monitor shift solenoids then monitor you input speed sensor and make a pid using the input speed and putput speed to calculate your gear ratio input/output. You can then see how long it takes for the shift to occur and dial it in. Its very useful to see when the solenoid is active. Be aware with a 4l80e segment swap the shift solenoid id's will be reversed in the scanner as it still thinks its a 60e.
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09-19-2017, 07:28 PM
#8
what i do is zero out the shift times. All it does is modulate line pressure to try and achieve that shift time, aka slip the clutches.... Just let it shift it can take it. with a stall i like to use mph as the determining shift point as well.
set up a pid in your scanner to monitor shift solenoids then monitor you input speed sensor and make a pid using the input speed and putput speed to calculate your gear ratio input/output. You can then see how long it takes for the shift to occur and dial it in. Its very useful to see when the solenoid is active. Be aware with a 4l80e segment swap the shift solenoid id's will be reversed in the scanner as it still thinks its a 60e.
set up a pid in your scanner to monitor shift solenoids then monitor you input speed sensor and make a pid using the input speed and putput speed to calculate your gear ratio input/output. You can then see how long it takes for the shift to occur and dial it in. Its very useful to see when the solenoid is active. Be aware with a 4l80e segment swap the shift solenoid id's will be reversed in the scanner as it still thinks its a 60e.
thanks for the heads up. thats a lot to chew on. hopefully i can get back to the track again before the weather sets in
09-19-2017, 09:24 PM
#9
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I set my mph low and use rpm to shift.
One thing I experience is it tends to take longer to shift with more power. This sucks if you move your boost around much. If I drive around on 10psi it short shifts compared to when I run 19.
I did some testing and commanded shift appeared to be spot on but the hydraulics in the trans just take some time.
Ive had luck setting the rpm low and raising it a little at a time until it's where I want. Each gear seems to have a different delay.
I use efilive but I don't think that matters for this.
One thing I experience is it tends to take longer to shift with more power. This sucks if you move your boost around much. If I drive around on 10psi it short shifts compared to when I run 19.
I did some testing and commanded shift appeared to be spot on but the hydraulics in the trans just take some time.
Ive had luck setting the rpm low and raising it a little at a time until it's where I want. Each gear seems to have a different delay.
I use efilive but I don't think that matters for this.
09-21-2017, 08:56 AM
#12
Hows your wiring harness and solenoids? Not all created equal, the German ones are nice. Pricey, but nice. local builder uses those on expensive builds. Old internal wiring can get sploogy over time too. Wont help your cause any if this is the case
I find its often mechanical issues when I blame the tune or computer
I find its often mechanical issues when I blame the tune or computer