Tuning a 4L60E with Transgo HD Shift Kit

[Taz]

Not a problem to have the Performance and Normal patterns the same - just serves to mimimize the dual shift patterns afforded by the Tow / Haul switch. I generally set the normal pattern to be firm, with near OEM PT upshift / downshift points. Then set performance (Tow / Haul) to be very firm, with increased PT shift speeds - for spirited driving / improved towing - depending on the application.

Nice project you have on the go ... great work so far ... read WeathermanShawn's praise in the other thread !!

Regards,
Taz

[blsnelling]

Try the attached file.

What's your logic behind making the 3-2 and 4-3 Throttle Kickdowns 100% across the board? Also, how can a slower shift time of 0.2 help the 2-3 shift?

[blsnelling]

Here's what I've got now.

My Modified_02.tun

[joecar]

What's your logic behind making the 3-2 and 4-3 Throttle Kickdowns 100% across the board? Also, how can a slower shift time of 0.2 help the 2-3 shift?

The throttle kickdown tables can interfere with the PT up/down shift tables... by setting them to 100% allows PT shifts to be controlled by the PT shift tables only rather than switching between PT shift tables and throttle kickdown tables.

The hydraulic hardware may be taking its time perhaps (for some reason or other); when the PCM has to meet 0.2 s it will successively increase the pressure rate until the time is met; try it to see if it makes any difference.

[blsnelling]

Gotcha. Thanks for the explanation. I'll set them all to 100% to see if the condition goes away. If so, I'll put them back like they are. Thanks a lot for all the help!

[Taz]

I leave mine at 100% ... FYI.

Regards,
Taz

[blsnelling]

That sounds very un-user friendly if you have to go WOT to kickdown a gear. Or am I missing something here?

[Taz]

PT upshifts / downshifts are controlled by RPM & vehicle speed - these are in the "Shift at VSS" and "Shift at RPM" folders. You definitely want a downshift at WOT (100%) - when you put your foot to the floor. If you've ever driven a 1980's version 700R4 transmission - you know how annoying an unwanted downshift is prior to WOT.

Keeping the WOT at 100% lets you tune the PT tables to suit your driving style - and will still allow cruising at high % TP. It also avoids potential conflicts between your Throttle Kickdown and Shift at VSS / RPM tables.

Regards,
Taz

[joecar]

The PT downshift tables have MPH on the vertical axis and TP on the horizontal;
any time the operating point (TP, MPH) crosses to below the curve the PCM commands the downshift;
so at some MPH if you increase TP, the operating point moves to the right and crosses to below the curve and you get the downshift.

All the F-car and Y-car calibrations came with throttle kickdown set to 100%.
Trucks tend to have some various curves for those tables.

The throttle kickdown tables are supposed to take precedence apparently, but I've seen a few cases where downshifts weren't happening or were delayed.

See this: showthread.php?3336-No-Kickdown

[blsnelling]

Excellent info guys. Looks like I'll be leaving it at 100%