Need help with throttle closure on stock ZL1

[BMWMD82]

Hey guys,
So I?ve read everything I can on Driver Demand and Peak Torque tables. I think I get what I need to do, but would like some clarification.

My real question is: Do the usual changes apply to a stock car? I?ve noticed big differences in throttle % and boost depending on conditions, temps, heat soak, etc. On the dyno the other day (making baseline pulls), everything looked normal. But it was warm out (81 degrees) and the blower was hot from a long drive (~150 degree starting manifold temp). Timing and power were down some, but throttle and boost were what I expected.

Fast forward to yesterday...and things were much different. The motor and ambient temp were cool. Timing was much stronger, but I?m greeted with erratic throttle and only 7-8 psi of boost because of it.

Do I just need to tweak the DD table, or does the Peak Torque table need adjusting as well? I haven?t added any power, so I?m questioning whether Peak Torque should be changed.

I found some good threads on this, but they really all apply to modified cars. I do have an intake on my car (no tune needed? supposedly), so maybe that?s contributing to my throttle closure. I don?t like messing with MAF tables without a wideband, so I haven?t touched it yet. It was pretty rich on the dyno, so I may take a little out.

Thoughts and opinions welcome!

Thanks

[BMWMD82]

PS: I don?t know why my phone changes apostrophes to question marks. Sorry about that.

[jsllc]

Without logging there is not true way to know if it is TQ management or some other issue. Logging will tell you what the problem is, IF you have logged enough and the right data. Very hard to tell what those PIDs would be now but you start with most spark, fuel, airflow modifiers and go from there. As silly as it sounds the car is behaving as programmed, and you may not be able to change it.

[BMWMD82]

I?ll agree with you that the car is probably doing what it is supposed to. It?s limiting torque, while leaving power on the table. I?m just trying to decide how best to reduce it. This can be done from what I understand.

I?m going to be doing a pulley and Headers soon, so it won?t be staying stock. I?m just trying to wrap my head around it and see what it can make by reducing the torque management intervention.

[jsllc]

There is no way to tell until there is a log with enough detail. Sorry but that is the only way to truly know. I would not assume it is leaving power on the table. Maybe just reducing power to achieve maximum for the current environment. Many times when it pulls throttle or timing it is doing so because of other issues that are unsafe to the engine, transmission and other drive-train items.

[BMWMD82]

There is no way to tell until there is a log with enough detail. Sorry but that is the only way to truly know. I would not assume it is leaving power on the table. Maybe just reducing power to achieve maximum for the current environment. Many times when it pulls throttle or timing it is doing so because of other issues that are unsafe to the engine, transmission and other drive-train items.

Here's a couple logs. One is from today, and looks good (no throttle closure or torque management spark). I made a few changes to the DD tables, Peak Torque, and MAF. I'm not totally sure if I eliminated the issue, but it looks better. The other log was from the stock tune file yesterday. Unfortunately, I was in the process of getting my Config set up, so I wasn't logging everything I wanted on the first one. But maybe you'll see something I don't.

And I get what you're saying. My thinking is this: In stock form, the engine is only allowed to make a certain amount of torque. Under ideal conditions, that torque level is exceeded and the ECU closes the throttle or pulls timing to reduce torque. I'm sure this is done for longevity/warranty reasons, but it also means the engine isn't making the power it could if the throttle is at 60%. I get why GM chose to do it. I'm just trying to keep the throttle open without screwing anything else up in the calibration.

[jsllc]

Please attach tunes when you can. I have not driven the new ZL1. What driving mode were these logs run under? There is TQ management going on but do not have the right PIDs to tel you why.

[jsllc]

Here is and example of PIDs from an e67 (2012-2015 ZL1)

[veee8]

If this is a manual trans ZL1, then the max torque per gear under the Engine TM, is likely holding it back. It is set at 650 ft lbs. and will close the throttle even on stock cars.

[BMWMD82]

If this is a manual trans ZL1, then the max torque per gear under the Engine TM, is likely holding it back. It is set at 650 ft lbs. and will close the throttle even on stock cars.

It is an A10 car, so those tables were all maxed out. It seems like the changes I made eliminated what I was seeing, but further logging is needed.

My Predicted Torque Commanded still shows to be above Maximum Torque, but I don?t see any limiting (throttle or Torque Management advance) in my last log.

I?ll post my tune files when I get home.

[BMWMD82]

[QUOTE=jsllc;511189]Please attach tunes when you can. I have not driven the new ZL1. What driving mode were these logs run under? There is TQ management going on but do not have the right PIDs to tel you why.[/QUOTE

I?ll post my files when I get to a regular computer. These were done in ?Touring? mode with TC turned off.

[SultanHassanMasTuning]

as mentioned post file to help/identify the issue

[8850]

Same problem here with my 2017 Z06. I can fix the problem with a couple % added to the 100% line in the DD table but then get way too much knock retard. If we find a solution I would like to know.

Here are two logs showing stock driver demand table and with the throttle partially closing around 90 mph. The other table with the 5% or so added to the DD table.

[jsllc]

Need more PIDs in log. Might try attached file

[lt1z350]

I have a 2017 zl1 a10 and with and logging and playing with a small mix of e85 to help lean it out a touch at the track I was averaging 38-45 percent tps though out a quarter mile run. The car ran 11.00@127 on stock tires with a 1.71 60 foot. It would shut the throttle down to 30 percent at about 12 mph killing my 60 foot then pick back up to 38-42 percent throttle and thats all the stock tune was giving me that day. It was cool out and was logging about 848 max torque and in the tune it is 854 I believe ( havent looked in a while) So with that 1 gallon of e85 in the car to about a full tank it was limiting the power that much. On a normal day I am seeing 68-78 percent throttle when has 93 in it and has run [email protected] with straight 93 so to me that shows how much the stock tune is limiting the torque by the throttle. I find mine to be a "strong" running car as sit near the top for posted times on stock tires with stock tune no bolt ons. Even in the heat and humidity of florida it went 11.47@126 that was totaly stock on a 90 degree day with around 2800 da at a sea level track humdity was near 98 percent. Seeing all this in my logs is why I believe bolt ons are useless unless you tune for it. The way I see this car playing with boost and throttle on the lauch I see why drag radials also dont help a stock tune car. I dont even see over 8 lbs till 3rd gear or so most runs and have about 17 time slips in 2000 miles on the car. I just sent off for the upadted tuning school direct injection book and they claim it helps explain all these issues a lot more then the old book I had. If have a lot of access to dyno time I would be happy to give you my 2 cents on the tune as I have been doing so much logging and preparing for tuning the car. I have had a lot of luck on my 2016 v sport keeping throttle 100 percent and making 20 psi when many claimed the trans not being tuned would get in the way of making power on the car. my trap speeds and weight come out to over 460whp on the car so getting a handle on this di stuff. Also have some bolt on ats/camaro 2.0t running 110 mph in the quarter mile. Spent a lot of time on my own building tunes. Like to have a chance to help with a zl1 and willing to spend time helping. I have a really good channels list for the car too just pm if want the help. Really curious what can be gained tune only on this setup. While I dont think power will be a lot I do believe if can keep the throttle open 100 percent from time of launch the time slip will show more then actual power gain at the rear wheels. there are a ton of tm tables in the way and if miss one of them its going to close the throttle and learned that pulling out a lot of hair on the v sport.lol

[8850]

Need more PIDs in log. Might try attached file

Here's with your configuration. Not sure this helps as I believe I lost traction about 70 mph and probably skewed my results. My drag radials apparently didn't hold very good even with the slightest moisture. It's been cold and now warm so the highway may have had some moisture.

[jsllc]

I missed one PID, sorry (you should add Torque Mgt Advance to the timing section) and your WB is missing from the fueling section. I see the issue on this pull. I do not see your tune posted. Please post and I can take a look at it.

[8850]

I missed one PID, sorry (you should add Torque Mgt Advance to the timing section) and your WB is missing from the fueling section. I see the issue on this pull. I do not see your tune posted. Please post and I can take a look at it.

Here you are...I can add TMA. Oh and I like Commanded Throttle Actuator too as it shows 100% when WOT.

[jsllc]

Okay you could try this. it will make it better or worse. I believe better. This appears to be a highly modified tune. Is it?

[8850]

Okay you could try this. it will make it better or worse. I believe better. This appears to be a highly modified tune. Is it?

Have not gone though all but with 32484 I get a box that says "Parameter out of range". Is this correct? The first two in your spread sheet are within limits. Stopped at this point on your spread sheet.

Yes, my tune is modified. Although mostly minimal changes. Timing advance is factory and fuel has been adjusted with my wideband to about factory Lambda values. All the idle changes were just to eliminate the engine starting so high. Factory start up is about 1300-1500 rpm and hanging for so long. My maximum speed was to make sure I didn't over run the speed rating for drag radials. I called either Hoosier or Mickey Thompson and they test up to 150 mph and no higher. Fan setting was just to my liking.
Thanks for all the help!