[arpad_m]

Originally Posted by SATINSTEEL1LE

This is disheartening. I have a 21 ZL1 A10 and would like to hit the 1k HP mark. So I would need to tune the trans to make that happen no matter what?

Why is it disheartening? You guys already have a way forward thanks to HHP, the tuning potential may not be as extensive as with the A8, but the TCM swap is a feasible avenue.

[JSH]

Originally Posted by arpad_m

Why is it disheartening? You guys already have a way forward thanks to HHP, the tuning potential may not be as extensive as with the A8, but the TCM swap is a feasible avenue.

This story is getting more complicated.

HHP tells me they have NOT found a way to delete 1st gear with a T87a / 2020+ A10. Instead, they say, "At the track we use manual mode and in the staging lane bump the paddle up to 2nd gear before the launch."

I've tried their method and it doesn't work with my current TCM tune. Perhaps this is a feature in their T87a 2020+ A10 tunes. Posts here say this can be done with T87a <2020 A8/10.

My current T87a tune still wants to occasionally try to shift to 1st at a stop, which causes some metal on metal, not good. My guess is that it's a valve body issue or shift / pressure solenoid issue, perhaps it drops pressure too fast, which might be adjustable. I'm not sure, but we'll work on it this year.

[radz28]

Originally Posted by 6spdhyperblue

Is the throttle held back in lower gears in a 22 SS a10 as well?

Radz28 you mentioned vtt and vve, are you saying that if you leave those stock it will play nicer with the oe TCM?

I couldn't tell you that, as I haven't seen a tune, but I'm sure it is. It's likely powertrain protection, but that's just a guess. What else would it be? I know diesels do something similar, too - I think Dirtymax's haven't for a while, but I thought I read Cummin's have. The point is - it's not new.

Simply and directly - I suppose you could say that it might play nicer, but it won't be correct. It seems the consensus is VVE and VTT control torque, and if they aren't properly modeled, as your car makes more power over stock, the tranny won't behave in a manor that compensates (and compliments, to a lesser importance) for the additional torque. That could mean it doesn't apply enough pressure to keep the clutches engaged, enough such that it will slip and increase wear and damage the tranny, for example. The TCM, basically, looks to the torque the ECM is calculating (in the VVE/VTT models), and applies what it thinks is appropriate pressure to keep from slipping. I can see this in the SCANNER. But if you're increasing MAF air flow, the ECM will increase it's torque calculation, too, to an extend I guess, so I don't really know. There's a Member here, whom I won't call out, that I've read a lot of posts from HPTuners, and wish he might chime in, but from what I can tell, the current convention is if you have to recalibrate the MAF for more air flow, you might need to recalibrate the VVE. If you need to recalibrate the VVE, you might need to recalibrate the VTT. If you recalibrate the VTT (or any of the others I already mentioned), you might need to recalibrate the DRIVER DEMAND tables. If you don't balance all of these (and more), sometimes, you'll get throttle closure or timing will get pulled to reduce torque within the limits the ECM/TCM want to see.

Basically - my point is that because Gen Vs are torque based systems, if the ECM isn't calculating torque correctly, you have to, essentially, "rape" the system to keep the throttle open and have commanded timing. I didn't really know it at the time (because I didn't have the TCM), but I was "raping" part of the system because of the torque limits. With the new TCM, my models are a lot closer to what they should be, and I'm not getting any throttle closures or timing reduction like I used to get. Maybe the simple combination I'm playing with doesn't require all this, due to it's simplicity, but I like to try to optimize what I have. I'm no expert, and just do this as a hobby, so I know I still have lots to learn.

There are some Members here that contribute a great deal of knowledge over on HPTuners. I won't call them out, because that's not cool, but I'd really recommend searching over there, too. I've learned A LOT from people here, too. I'm still learning.

Originally Posted by JSH

This story is getting more complicated.

HHP tells me they have NOT found a way to delete 1st gear with a T87a / 2020+ A10. Instead, they say, "At the track we use manual mode and in the staging lane bump the paddle up to 2nd gear before the launch."

I've tried their method and it doesn't work with my current TCM tune. Perhaps this is a feature in their T87a 2020+ A10 tunes. Posts here say this can be done with T87a <2020 A8/10.

My current T87a tune still wants to occasionally try to shift to 1st at a stop, which causes some metal on metal, not good. My guess is that it's a valve body issue or shift / pressure solenoid issue, perhaps it drops pressure too fast, which might be adjustable. I'm not sure, but we'll work on it this year.

It seems to me that we have to get into the burnout box, run the car through at least 2nd to heat the tires, but leave the car in 2nd so it doesn't downshift back to 1st, and then you should have your 2nd gear start. I have to wonder how tough it is to launch the car in 2nd gear though... Maybe it isn't any harder on the tranny, but I'd like a consensus on that before trying it much. It's weird yours is doing that. I don't do it enough, just driving around, for that to have happened to me yet. Maybe the car would do it, like yours, if it were driven more. Hmm...

[JSH]

Originally Posted by radz28

It seems to me that we have to get into the burnout box, run the car through at least 2nd to heat the tires, but leave the car in 2nd so it doesn't downshift back to 1st, and then you should have your 2nd gear start.

Continuing, the problem is that, if I start the burnout in 1st, shift to 2nd, roll forward and stop, it then shifts to 1st . . . sometimes. We're working on it.

[radz28]

Interesting...

[KingLT1]

Originally Posted by 6spdhyperblue

Is the throttle held back in lower gears in a 22 SS a10 as well?

Radz28 you mentioned vtt and vve, are you saying that if you leave those stock it will play nicer with the oe TCM?

The throttle is limited by the torque vs gear vs rpm table in the tcm. The A8 and A10 in all variants have this. Stock power levels the throttle is limited the most from 1st gear and 3rd gear. It's not super noticeable on a bone stock car because the torque limits are close to what the engine actually makes. However once you start adding power the throttle just closes more to stay around those torque limits. On just a flex sensor, cai, e50 Zl1, the throttle was only opening 52% from 3-5k then full open by 6k rpm in 3rd gear. You can change all the torque stuff on the ecu side and it won't do a damn thing if you don't change these torque limits on the tcu side as well.

For big power cars messaging these tables to help traction down low could be useful. For lightly modded stuff I would want it all disabled.

On my brothers bolt-on A10 ZL1, since disabling trq vs gear limits, the boost now hits 12psi vs 6psi on the hit due to the throttle opening all the way. 4th gear roll now hurts the stock SC3 tires. Which are not going to be on the car much longer. It's getting forgelines and a set of triple8 toyos.

No need to do much with VVE or VTT on lightly modded stuff. Once you change the airflow dynamics of the engine(heads/cam/compression) then VVE should be addressed. I like to blend about +10% into the VTT to firm up the shifts and make the trans a little more responsive.

I know some despise MAF only tunes but they work fine on the gen 5 platform for most applications. Most don't realize that GM disables dynamic airflow and above 4k rpm anyway for PE mode. If the MAF ever failed the ECM would default to Reduced Power Mode anyway and pull a lot of torque unless your tuner went into the driver demand table and matched the RPM mode to the other drive modes which I wouldn't do.

[JSH]

Solution: It will shift to 1st gear in Auto. So, I launch in Auto and shoot for pulling into Manual between 4500-5000 rpm. Admittedly, it's accelerating so fast in first that it will be difficult to hit the same rpm consistently, but... it can be done

[radz28]

07.26.22 - UPDATE:
I learned what happens when you don't disable the code you are required to when you do this swap: You get a bunch of weird values from the transmission gear PID for what seems like 9th and 10th gears. There are more than 4-or-so-codes, though, during these shifts and in these gears, so I wonder if TCC has anything to do with them, too.

Remember to disable the code, lol. The car seemed to behave like usual, but I noticed the weird values, and remembered during my tinkering, I didn't turn-off the code. Oopsy...

[JSH]

Originally Posted by radz28

07.26.22 - UPDATE:
I learned what happens when you don't disable the code you are required to when you do this swap: You get a bunch of weird values from the transmission gear PID for what seems like 9th and 10th gears. There are more than 4-or-so-codes, though, during these shifts and in these gears, so I wonder if TCC has anything to do with them, too.

Remember to disable the code, lol. The car seemed to behave like usual, but I noticed the weird values, and remembered during my tinkering, I didn't turn-off the code. Oopsy...

Mine still throws codes and shows the check engine light. I'm not sure how to go about correcting this short of uninstalling the 87a and starting over. But the car runs great.

[radz28]

Originally Posted by JSH

Mine still throws codes and shows the check engine light. I'm not sure how to go about correcting this short of uninstalling the 87a and starting over. But the car runs great.

Really? Do you know why (I'm sorry if that sounds stupid - I'm honestly asking)? Have you tried to download the stock tune and start over from there?

[SATINSTEEL1LE]

I've got my HHP T87a sitting on the shelf waiting for the rest of my parts to show up so I can get everything done at once. 21 A10 here.

I have powertech performance here in Tampa doing the install and tuning. Their tuner is very familiar with Chuck/HHP and how to tune these. There is also a document that Chuck sends with the TCM that has all the codes you need to disable. Let me know if you guys need to see that sheet.

[JSH]

Originally Posted by SATINSTEEL1LE

I've got my HHP T87a sitting on the shelf waiting for the rest of my parts to show up so I can get everything done at once. 21 A10 here.

I have powertech performance here in Tampa doing the install and tuning. Their tuner is very familiar with Chuck/HHP and how to tune these. There is also a document that Chuck sends with the TCM that has all the codes you need to disable. Let me know if you guys need to see that sheet.

Yes, please post the sheet thx

[SATINSTEEL1LE]

Originally Posted by JSH

Yes, please post the sheet thx

Here you are.

[JSH]

Originally Posted by SATINSTEEL1LE

Here you are.

thanks