8HP70 - What triggers PERF Upshft tables for timing and pressure

[Anakin]

I wonder what triggers the UPSHIFT PERF PRESSURE and UPSHFT PERF PRESSURE ? In other words, what could cause the TCM to switch from NORMAL to PERF ?

For downshift, it's pretty straight forward, I soon the transmission downshift more than one gear at high throotle it's PERF mode. For exemple, if I make a downshift from 3rd to 1st, the transmission TCM switch to PERF mode and stays on this mode until throotle release. It will shift 1st to 2nd fast and hard, I cannot replicate this shift form a dead start no mater what I do.

How to active PERF mode during normal upshift ?

Reference : 2019 Ram 1500 Hemi 8sp (8hp70) DS Body Style

Perf 1.PNG
Perf 2.PNG

[DodgeBoy_8HP]

I wonder what triggers the UPSHIFT PERF PRESSURE and UPSHFT PERF PRESSURE ? In other words, what could cause the TCM to switch from NORMAL to PERF ?

For downshift, it's pretty straight forward, I soon the transmission downshift more than one gear at high throotle it's PERF mode. For exemple, if I make a downshift from 3rd to 1st, the transmission TCM switch to PERF mode and stays on this mode until throotle release. It will shift 1st to 2nd fast and hard, I cannot replicate this shift form a dead start no mater what I do.

How to active PERF mode during normal upshift ?

Reference : 2019 Ram 1500 Hemi 8sp (8hp70) DS Body Style

Perf 1.PNG
Perf 2.PNG

In case performance mode is available in the vehicle, it will activate "PERF" shift maps.

In case not available, it would be required to tune normal mode to become the way you would like to have

[mike_ct]

Did you log and see perf pressure? If you like the firm shift, why not copy the perf tables to normal?

[LilSick]

that is determined by either a button, or a aggression counter

[Anakin]

I did (I Use similair data from PERF to my Normal tables not a straight copy-paste) but the internal algorithm decrease shift pressure, increase shift time and makes a "fast & hard shift" long & smooth again after few weeks. Dodge calls it "shift quality"

I'm looking for a way to either keep the transmission (find how to do it with HPTuner) in PERF mode were it keeps fast shift and higher pressure than the normal mode or a way to limit the adaptation built in...

[Anakin]

Thanks, it makes sense.
I was able to "limit" the aggression counter effect in the Shift Scheduling Tables, limit the acc factor and it works ! But i'm unable to do it on the timing table nor pressure table. I wrote to HP Tuner and they are not working yet on a feature to limit the adaptation.

So, no matter what I do my truck will return to slow and smooth shifts after a while (3 to 4 weeks) and stays smooth until I reset the adaptation parameters or reflash the same tunne in it.

[DodgeBoy_8HP]

Not completely true

In case the tune is done in a way that the system understands what you want to do, it is fully possible to have "fast & hard shifts" to last

Adaptation is a big part of the shift, however, it can be worked on

[mike_ct]

did you alter the schedules in the aggression section? or change the aggression table to use specific maps? some of these are read only on mine.
I have wrangler 392 operating system on my ram truck, so it's slightly different and some tables are read only, and I dont have buttons to get into sport/perf either.

[LilSick]

performance mode is good but max mode is where its at : )

[DodgeBoy_8HP]

did you alter the schedules in the aggression section? or change the aggression table to use specific maps? some of these are read only on mine.
I have wrangler 392 operating system on my ram truck, so it's slightly different and some tables are read only, and I dont have buttons to get into sport/perf either.

It depends on the baseline TCM and vehicle application.
Sometimes it is better to change aggression table (or copy from other OS), sometimes combination of shift schedule/torque management/pressure/timing/torque converter is the solution.