6-2 downshift on 6l80 is pretty harsh on my yukon
Tq mgt is stock
Base tune on 5dpf suggestion
I change shift timing on 6-2 to have an higher value
I need suggestion because when i slam it, I can hear a bang in the trans.
6-2 downshift on 6l80 is pretty harsh on my yukon
Tq mgt is stock
Base tune on 5dpf suggestion
I change shift timing on 6-2 to have an higher value
I need suggestion because when i slam it, I can hear a bang in the trans.
Post a file for us to look at.
A log would help too.
6-2 is pass-through-neutral. Go to your spark timing tab and check to make sure that tq management advance is still allowed -20deg. If you set that table to zero deg or higher, you are basically causing a WOT neutral-drop during that down shift and it's very harsh (as you've noted).
Spark minimum table is close to zero at wot...
Make it more negative and see if it helps. I keep negative timing in the lower rpm regions all the up to 4,000ish rpm and slowly ramp it down to like -5ish above that.
I can't say I've done many 6-2 downshifts because I don't allow for 6th gear until over 50mph so if I floor it above that it just shifts into 3rd. I could see that downshift if it was in 6th gear by 40-45mph though.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Base tuning 5Fdf following your recommandation was awesome
This is the only trouble i have when i floor it
Tq management is still untouch
Should u disabled neutral downshift ?
Put that table back to stock and then re-test 6-2 downshift. That table or the one I mentioned will hold spark too high during the pass-through-neutral downshift. Your right foot is on the floor when this downshift is commanded; you MUST allow the ECM to limit torque during this move (through neutral), and this is how it does it. You can have a 500+rwhp car still able to make this downshift, and quickly, but the ECM needs to be able to pull spark. The two tables I have mentioned are very "blunt instruments".
If it's STILL rough, and it shouldn't be, set all of your downshift times and pressures back to stock and re-test the downshift. This will tell you where to go from there.
Last edited by Frost; 11-12-2019 at 09:52 AM.