GM Performance ECU - tunable for 33" tires?

[Portland68]

Maybe a dumb question but I am looking at the GM performance engine harness which includes ECU PN 19354329. Looking through the tech document I see it doesn't recommend tires greater than 30" - I currently have 31" tires and am planning on 33" for my final build. Will this unit be tunable or should I just go for a PSI harness? I do like the plug and play aspect of the GM harness as this is all new to me, but not if it's going to risk damaging my transmission due to incorrect settings. Thanks!


https://www.gmperformancemotor.com/parts/19354329.html

[LS short box]

What trans are you going to use? Which LS engine?
On my auto LS swaps the tuner could tune the shift points as I liked.
I like and use Speartech or Howell harness and ecm for the base tune.
Nothing against PSI I'm sure they can help in the same way.

[Portland68]

I'm likely going to with a gearstar built 4L65E mated to the 430 horse crate LS3 from GM performance. I was able to reach out to the supplier and it sounds like I can get a tune for the 33" tires, it just won't come out of the box ready to go which is a bit disappointing but seems to be the name of the game with an LS swap (again this is all new to me but was hoping to avoid dropping $ on a tune off the bat after what will already be an expensive project).

[LS short box]

On my LS swaps I don't have 4th gear or TCC lock out until 40-45 mph to keep from lugging the engine.
Make sure your ECM supplier knows your rear end gears.

[cj847]

Wow, this doesn't make sense.

On my swaps (gm factory harness and computers) the tuner needed to know everything.

What maf sensor, what injectors, what rear gears, what diameter tires, etc, etc. That was just for a start-up tune. In my case, they are all stock junk yard stuff so I never had them performance tuned. Have been running flawlessly for about 6 years.

I don't see how there would be any limit on tire size.

If you're buying all new why not go with a "connect and cruise" set up?

[LS short box]

If you aren't concerned about brag HP numbers a "drive" tune will get things dialed in nicely.
Trans shift points. Idle. Speedo calibration. Turning on/off the fan at the temps you like you want on the drive tune.
It won't cost nearly as much a chassis dyno tune. IMO well worth it.

[Joyridin]

I have this set-up in my car. I am using a T56, so I am sure it is slightly different than yours, but you can pretty much do anything you want with it. I had a S/C on my car using this controller. As long as you or your tuner can do it, it can be done.

Don't forget though there is no CANBUS, so all your gauges have to be independent of the unit. Not a big deal on an older vehicle, but if you are looking to run new style gauges, there is no provision for a CANBUS.