[livewire516]

tldr; I'm trying to consider how early on it makes sense to start tuning my van. There's other possible drivetrain mods in the future that would probably require a tune, but it seems like it'd realize some efficiency gains now. I might as well start learning?

My 2009 Express 2500 has a GM LY2 4.8L V8 (Technically considered Gen IV, but no variable valve timing or cylinder deactivation) mated to a 4L80E. The rear gear is either a 3.73 or 4.10 (the RPO codes seem to be missing, so I guess I'll either need to jot down RPM and MPH in a known gear with the TC locked up or pester a GM dealership to run the VIN).

I'd probably stick with a market-leader like HP Tuners, because they seem to have a large user-community and a lot of documentation.

It seems like I could immediately realize efficiency gains by modifying the transmission's shift points, so I can upshift sooner despite moderate load or a somewhat open throttle position, without having to play so much with the throttle trying to trick the TCM while driving. There are "torque management" parameters in the transmission control unit to mitigate premature wear; I'm glad those exist and I doubt I would touch them.

Later on, it seems as though I would be able to change shift points again if I switch to a 3.43 rear gear (something I don't believe the 4.8 L GM van got from the factory). I fantasize about putting a manual transmission in here at some point; if that happened, I suspect tuning would also be warranted.

I don't know how much can be realized from tuning the ECU itself; this is something I would do very conservatively. I'm not interested in trading MPG for NOx.