how to dyno a 6l80

[ayousef]

without it downshifting of course? Anyway to lock it in 4th gear and not have it downshift?

This is on a 2010 Silverado.

ideas?

[Area47]

without it downshifting of course? Anyway to lock it in 4th gear and not have it downshift?

This is on a 2010 Silverado.

ideas?

drop the wot downshift speeds to a mph where it won't downshift.

[ayousef]

drop the wot downshift speeds to a mph where it won't downshift.

I tried even putting zero on the downshift tables, it STILL downshifted.

[camaro1]

tap shift

[ayousef]

tap shift

our trucks downshift automatically on WOT even in manual mode...

Any other suggestions?

[Ben Charles]

VCM controls should allow you to keep it in gear.

[bluegoat06]

In the G8's, i can put her in manual mode in 4th gear, i do my 4th gear dyno run at 2500rpm if i wanted to, no auto downshift when in manual unless you go really low in the rpm. the factory has the G8's doing the auto downshift from manual at around 18mph (4-3), and 11mph (3-2)

You can adjust this behavior going to tap up/tap down (normal), and adjust the the downshift rows for whatever speed you'd like the thing to downshift automatically, or if you don't want auto downshift, just set the entire row to a mph you know you won't hit int the downshift.

[LSxpwrdZ]

VCM Scanner controls normally allow a gear to be held IF you have the Tranny Diagnostics parameters setup properly for the VCM Scanner controls.

[stan]

VCM Scanner controls normally allow a gear to be held IF you have the Tranny Diagnostics parameters setup properly for the VCM Scanner controls.

Can you explain to this dummy what exactly you meant about the proper setup??

Also would you dyno it with the stock convertor locked up or unlocked on a 550 flywheel hp (hopefully) 2012 6.2L with a blower?? I assume you could do that with VCM controls as well if you wanted to.

[LSxpwrdZ]

Basically in VCM editor go to the Tranny Diag. tab and you'll see on the right side halfway down the page there is vcm controls parameters set via speed etc. Set those tables up so that you can fully control the transmission in the scanner. Otherwise outside of those boundary's the scanner controls are ignored.

[stan]

I see what your talking about. Didn't realize the scanner wouldn't work under set conditions like that.

Do you lock the convertor on the dyno usually??? Seems it might be more consistent and allow you to log lower RPM data like you can with a manual transmission.

[andrewquant]

Sorry resurrect an old thread (proof I used the search function ) but I'm having the same problem trying to dyno my 6L80 car. The shop wants to do a 4th gear pull but the car keeps downshifting into 3rd even though I have VCM Scanner Command 4th gear = ON. The TCC lock worked with VCM Scanner, but not the gear selection. It would shift down to 3rd and then afterwards into 5th and 6th. What settings do you have to change to make a 6L80 play nice with a dyno?

[sevinn]

Sorry resurrect an old thread (proof I used the search function ) but I'm having the same problem trying to dyno my 6L80 car. The shop wants to do a 4th gear pull but the car keeps downshifting into 3rd even though I have VCM Scanner Command 4th gear = ON. The TCC lock worked with VCM Scanner, but not the gear selection. It would shift down to 3rd and then afterwards into 5th and 6th. What settings do you have to change to make a 6L80 play nice with a dyno?

Make sure under transmission>general cmd gear control limits your max rpm and mph are suitably high as well as the upshift min and downshift max speeds.

[andrewquant]

^^ Thank you sevinn! My data log seems to indicate this was the reason. The MPH and RPM of the mess ups match the settings. I will adjust and try again. Thanks