Have to agree! Used this tool for the first time and the visual is great!
Have to agree! Used this tool for the first time and the visual is great!
For reference:
This is what post #1 is saying.PT shift table relationships:
basic relationships:
1->2 curve should be above 2->1 curve;
2->3 curve should be above 3->2 curve;
3->4 curve should be above 4->3 curve;
. . .
additional relationships:
3->2 curve should be above 1->2 curve;
4->3 curve should be above 2->3 curve;
. . .
this can be summarized as: the curves cannot cross anywhere;
if they cross anywhere, then you will not be able to predict what gear the TCM selects when the operating point hits the cross.
This old thread and the spreadsheet it contains has really help me to visualize my shift points, and I would like to thank SSpdDmon, joecar and the rest of you! I've been experimenting with the shift points and comparing to stock files and others. I've attached my current version, I'd be interested in any input.
Some comments on shift curves:
- you can space out each shift curve and its corresponding upshift curves so that they have more vertical distance between them (see 2002 Camaro A4 tune file), this will improve drivability (i.e. engine rpm "feel" will better match "urgency" of throttle position; i.e. for these pairs 1->2 and 2->1, 2->3 and 3->2, 3->4 and 4->3; when editing, remember to maintain this relationship:
- same with TCC apply/release curves, space them out (see 2002 Camaro A4 tune file), driveability will improve.PT shift table relationships:
basic relationships:
1->2 curve should be above 2->1 curve;
2->3 curve should be above 3->2 curve;
3->4 curve should be above 4->3 curve;
. . .
additional relationships:
3->2 curve should be above 1->2 curve;
4->3 curve should be above 2->3 curve;
. . .
this can be summarized as: the curves cannot cross anywhere;
if they cross anywhere, then you will not be able to predict what gear the TCM selects when the operating point hits the cross.
Then when done editing, set all the WOT MPH shift parameters to the same values at the 100% columns in the PT shift curves.
If it's a street car, then you can get muclecar feel if you unlock TCC at low VSS.
I meant push the TCC release curve down further, for example look at 2002 Camaro A4 tune file, the 3rd TCC release and 4th TCC release are fairly flat down low... if your PCM keeps TCC applied on zero throttle, having the 3rd/4th TCC release curves low keeps the TCC applied until car is going too slow for TCC, but while above this it feels like a manual tranmission, and makes engine growl when you release throttle (i.e. musclecar feel).
Last edited by joecar; May 27th, 2015 at 11:05 PM.