want to know what needs to be changed for shift points to remain the same RPM with the 4.10's that they were with 3.42's.

using Tunercats.

 

I'd try just going into the TOOLS section and clicking on SPEED CALIBRATION and changing to a 4.10 and see what that does. It kept my shift points the same except for WOT. I had to tweak those to get them where I wanted by going into the mph/rpm tables and setting the rpm where I wanted and lowering the mph values.

 

Not sure what software you are using. I am familiar with TunerCat. I don't believe there's a way to directly scale the shift points. But, what I do is simple scale the shift tables. Here's how: divide your old gear ratio by the new one: 3.42 / 4.10 (this equals .83414634). Then, multiply this number by every value in your shift table. Let's say below is the first 5 rows of your shift table:

11 19 34 9 9 28
11 20 35 9 17 28
12 21 36 9 17 28
13 22 38 9 17 28
15 29 40 9 17 28

In TunerCat, you can scale a whole group of cells. If you did this, the result would be:

9 16 28 8 8 23
9 17 29 8 14 23
10 18 30 8 14 23
11 18 32 8 14 23
13 24 33 8 14 23

Make sure you scale: Normal Up/Down Shift points, Cruise Up/Down Shift points, Hot/Cold Kickdown Up/Down shift points, TCC engage and TCC release

If you want more help with it, send a copy of your calibration file and I'll fix it up for you. vince@trifectaperformance.com

 

we are gonna try this today and see what happens.

thanks.