2.0t ats tuning

Looking for a little guidance in tuning my car. Been tuning for around 12 years but first time on little motor boosted vvt stuff. As I have been reading you can have gains in cam tuning before even touching the boosted side. I have been playing with it and still having this boost spike then drop in high rpms and see many have complained of it but no one has posted a direct fix just it is sometimes in the knock airmass table which I dont understand it enough to know what direction to go on it. Seeing 250kpa then will drop to around 216 then flux up to 220 and back down. I see some of you have posted big numbers on the hhr and cobat stuff I guess that is a similar setup turbo vvt so looking for anyone that would like to get their hands in on this and help me make the most out of it safely so I dont tear it up. I build transmissions for a living and have fixed all of these that are run in these cars on this site so welcome any questions to help any way I can and I also have mine tuned for nice crisp shifts but not abusive and will share anything I have and help get yours shifting how you want it. Thanks in advance for the help.

Knock air mass table correlates with cyl air mass. I've found that if cyl air mass gets too far above it, the throttle closes and desired boost falls. The max torque tables can also cause the throttle to close if TQ spikes too high. Have you raised the duty cycle at 6900 rpm?

Have you made any changes to knock air mass? If not, start raising it up from 2 to -4. Try 1.3 for 2500 and above, except 1.4 at 5000 rpm. You can then raise it slowly from there.

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Originally Posted by ATS4me

Knock air mass table correlates with cyl air mass. I've found that if cyl air mass gets too far above it, the throttle closes and desired boost falls. The max torque tables can also cause the throttle to close if TQ spikes too high. Have you raised the duty cycle at 6900 rpm?

Have you made any changes to knock air mass? If not, start raising it up from 2 to -4. Try 1.3 for 2500 and above, except 1.4 at 5000 rpm. You can then raise it slowly from there.

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Yea I have changed that and a lot of other tables that I have read about from others sharing what they have learned. No one will post up a tune to help in the right direction to even know if heading right way. I have got the trans really working good so willing to trade off that info for engine info for anyone willing to actually send me a good tune. Not like trying to make money we all spend time doing this and learning off what others have done so not sure why people don't share more as I thought that is why we have this whole forum in the first place. I spent over 100 hours getting my 2007 Tahoe to get over 20mpg and make around 35 more hp on the tune alone and share it with anyone that asks. I know it is hard work but I believe what goes around comes around and might give out a lot but in the end it always comes back. I guess that is why my wife and I are foster parents. So anyone that can take the time to explain the tables I need to adjust or send me a actual file I can look at would be great. I will give back any way I can with trans help or even some of my other tunes. I doubt anyone needs a 1992 turbo 383 formula file but you never know. Lol seems the cobalt guys are a lot more quick to just give up a file and share that or not many ats tuners out there yet.

I agree with the sharing aspect on this forum. I'm not sure why folks want to make is a guessing game and only providing hints to issues they claim that they figured out. Here is what I have so far. The only problem is that the power is hit or miss above 4800rpm. I need to data log more and see what the limiting factor is. I am running 93 octane.

The reason is because these are very difficult ecu's to understand and tune. What the original jedi masters from LNF's found out was that when they posted tunes, shops would copy/paste and sell these people's hard work for $500/pop. Sharing is definitely important. But, teaching someone HOW to do it is better than WHAT to do without understanding why.

As for the oscillation in boost, not surprising. It happens on the stock LNF tune, too. Funny to feel at WOT. Boost goes to 14.5->12->14->12.5. It's going to take some experimenting to figure out all the limiters and how to get steady boost and timing control.

I Haven't posted my tune because this is my first turbo car and not sure I'm giving 100% correct advice. I've also noticed that some seem to crank everything up and let TM control the car from over boosting the midrange. I've tried to move TM out of the way and control boost with knock air mass and the duty cycle. If someone mixes approaches, it could be knock central at 4,000 rpm. If you post the tune I'm happy to look at it and offer thoughts.

I also like having the what, how, and why explained to go along with the tune as codename bil doe mentioned.

I reduced the knock air mass per what ATS4me suggested and the tune is a little more consistent. ATS4me can you explain how you are moving the TM out of the way?

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Originally Posted by codename Bil Doe

The reason is because these are very difficult ecu's to understand and tune. What the original jedi masters from LNF's found out was that when they posted tunes, shops would copy/paste and sell these people's hard work for $500/pop. Sharing is definitely important. But, teaching someone HOW to do it is better than WHAT to do without understanding why.

As for the oscillation in boost, not surprising. It happens on the stock LNF tune, too. Funny to feel at WOT. Boost goes to 14.5->12->14->12.5. It's going to take some experimenting to figure out all the limiters and how to get steady boost and timing control.

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Ok I see your point 100 percent on that then not to just post something u spent weeks figuring out just to have some scum actually put their name on it and make money when your intention was just to help someone out. I have gone as far as reaching out to the guy Greg I believe that wrote the gm software tuning book to see if it had stuff pertaining to turbo cars before I dropped 75 bucks on a book for nothing. I guess it is all about understanding how the different tables coralate to each other and how changing one may totaly affect another. So not changing all together keeping all tables linear you may change the one and not make a change overall. Very complicated when don't have a basic understanding of what each table even does. I have been reading a lot and see bill here knows his stuff. So to have your input would be great. Could I send u a log and tune and get some advice? I don't have an issue posting my tune so will so others can see where I am. The worst thing is the inconstant boost at upper rpm. I guess gone are the days of a spring keeping it at a steady number and the worst issue is the creep up you may get and if tuned for that high. I miss that now. lol at work so will post this evening a log and tune for anyone to comment on. You can see the spike then drop 250 lap to 216 then goes between staying more to low side when gate is set at 23 lbs.

The key with the ATS is going to be the same as the GXP and Cobalt SS - people will have to start experimenting to figure out a) what the tables do, and b) develop some understanding of how they interrelate. It's this second point that will generate a ton of "ah hah!" moments. You'll constantly think you've got it locked until you get to the next table you hadn't touched yet.

You'll find there are some tables that aren't worth touching. On the LNF, the optimum lambda is a prime example from my personal experience. It alters way too much that we don't have access to and can be very dangerous.

I haven't started messing or studying the ATS yet, but I will soon. In the future I'm looking to either race an ATS 2.0T or go with ATS-V.

Things I would shoot for when trying to unravel the mystery of this ecu:

1) Develop an understanding of as many tables as possible that the ATS uses. I glanced at the ecu and it looks to be very flexible for multiple platforms. Find which tables affect you.

2) Start to build a relationship between the tables and how they affect each other versus what you're trying to achieve.

3) Use this knowledge to develop a method to get the ecu to do exactly what you want. You don't need to access, understand, or change everything if you can accomplish full control with fewer tables.

So I guess the question is how much of the lnb will translate over to the ats as far as what tabes do and mean? I will read if it is out there to be read and that is the issue with the ats nothing really to help I really dont think anyone has really figured it out and why they all dance around what they think will work. I have seen some lnb cars make some impressive numbers and seen some posted tunes that look way different in a good sense to the ats. same tables but smoothed and with higher numbers. My problem prob like a lot of us out there this is a daily driver and if I tear it up doing something stuipid my wife will have my ass. It is her car I guess as she drive is 90% of the time back and forth to work and I have my tahoe. So that car goes down because I decided to exp with it I am done. So to know the safe way to do this would also help. A list of tables that work together to achieve a steady amount of boost. Seeing it fall to lower than the stock value is discouraging when you feel how hard it is pulling for the few seconds it is actually at 250kpa then just to watch it sink and feel the car go flat. Here is where I am for those that care to look and comment on it. Maybe a lnb guru will care to look and comment and help me achieve a steady 23-25 lbs. even to know what to do then I figure out the numbers. It is more gratifying to figure it out I will say that but that push in the correct direction sure would be great.
one thing if anyone knows it. Is there any place or book that you can go to or get that will actually describe how the tables work and work with each other? This isnt like when I did my 2007 tahoe and if I goofed on a table I could just put it back. The possibility of an over boosted engine and busting a piston is real and worse than that would be a run away throttle turning into a big wreck and dragging someone else into your mess is something that could really happen. Why I am trying to do this right and not just go throwing numbers in tables and taking large risks. Besides I am afraid of the wrath of my wife if the car breaks. lol
so here is a log to show what it is doing at the beginning is a good run from a stop to around 100 mph
then the most current file in the car that made that run.Attachment 43836Attachment 43837

Email me your stuff. I'm curious. [email protected]. As for experimenting on your car I would say just don't do much to it. I don't feel people should play around with a vehicle they rely on. Just my feeling towards it.

Maybe I uploaded it wrong but it is at the very end of my last post. I just did an attachment and saw it on the screen hit the include in post button and that is how it showed up. Log is first with a 0-110 run and then my file after it. If not right let me know how to repost and will do soon as get home from work and will email it direct to u mike and thank you. Yea as much as I want to make the car fast on the other end I didn't need to make a mistake learing it as it just isn't as forgiving as my naturally aspirated stuff has been in the past which I am very good with now. I have tuner cat so been tuning a while but this electronic boost is tough. If could just slap an old school turbo with a spring style blowoff and wastegate on it and keep all current driveability and wouldn't cost an arm and a leg that would be my road to head down. Easier to pick a spring to set boost levels and turn a knob in a vacuum switch over all this. Lol I apprecieate all feedback so far and if I can help anyway on any other vehicle just ask. Really good on the late model ls based cars and trucks I have the software to do pretty much any of them with tuner cat. I don't want a free ride here and if able to give back to community I will any way I can. ��

So I am looking at all of the boost control setting in the Engine>Torque Management>Turbocharger section and I am trying to make sense of the maps here. The best way I can do that is to try and relate it to my Eboost controller I use on my other cars. This is the best as I can explain it:
Wastegate Open Boost: Is the gate pressure. It is at this pressure that the wastegate will open then rely on duty cycle to manage boost pressure.
Base DC: This is the duty cycle that manages the boost pressure after the wategate opens per the above setting. The higher the % number you enter the higher the boost will be until you hit the Boost Max setting.

Boost Max: This is the pressure setting that will open the wategate fully 0% duty cycle if the threshold is exceeded.

Pressure Delta Factor: Think of this as a way to slow the turbochargers ability to build boost. It is a multiplier. IE a 1.4 entry in the box 3000RPM will allow a raise in boost pressure of 11psi between 2500RPMs and 3000RPMs if the pressure at 2500RPMs is 190kPA (12.86psi) * setting of 1.4 = 266kPA (23.88psi).

Knock: Is the allowable cylinder airmass in grams per cylinder allowed at a given RPM for a specific ignition timing. What I am not sure here is if this is based on Ignition Timing Advance (SAE) or something else.

I have created a spreadsheet for me to plot Engine Tq, Cyl Airmass, MAF, Manifold Pressure, RPM, HP (that I calculate), and kW (which I also calculate) from my data logs. These metrics seem to be the drivers for the X/Y plots and points of the maps. I am trying to match all of these up so that the maps work together vs. over stepping boundaries and closing the throttle and/or pull timing. I attached the spreadsheet. Feel free to use it. FYI the psi and PR conversions are based on sea level 14.7pis baro.

An example of using the spreadsheet is trying to pick a desired kW/HP target then matching the engine TQ, Cylinder Air Mass, Manifold Pressure, and Pressure Ratio. from my data logs. Next I take those results and plot them in the maps so they match up. Lets say I want roughly 230kW at 4500 RPMs. From one of my data logs I saw 227kW resulted with 360tq, 1.6 g/cyl, 255kPA, 1.52 PR, @ 4438 RPMs. Now I can use this data in the tunes

TM>General>Maximum Torque maps I can plot the 360tq target at 4000-4500RPMs.

TM>Engine>Driver Demand: I can't do sh!t because it is based on vehicle speed and not RPMs GRRRRRRRRRRRRRRRRR but I do know that my demand can be around the 230kW target.

TM>Turbocharger>Knock: I know that I will need to be near 1.6g/cyl in the 3500/5000rpms range under good timing conditions -2* to 4* area.

I think knock air mass is the target air mass based upon knock present. That's why it falls when knock increases (i.e. KR is a negative change to timing). I unwittingly tested this when I accidentally forgot the 1 in a planned use of 1.4 that I had entered in the 6900 column. Shortly after the car went past 5000 rpm, the desired boost dropped liked a stone and by 6000 rpm, the car was basically not accelerating.

However if you raise knock air mass too high, it will crank the boost high enough to get into knock unless boost is limited by the TM settings or by the wastegate duty cycle.

My pressure delta is basically stock. A little higher at 6900 may be helpful. I did not see any advantage from raising it at lower rpms, but I didn't raise it as much as the 1.4 as used in the example.

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Originally Posted by ATS4me

I think knock air mass is the target air mass based upon knock present. That's why it falls when knock increases (i.e. KR is a negative change to timing). I unwittingly tested this when I accidentally forgot the 1 in a planned use of 1.4 that I had entered in the 6900 column. Shortly after the car went past 5000 rpm, the desired boost dropped liked a stone and by 6000 rpm, the car was basically not accelerating.

However if you raise knock air mass too high, it will crank the boost high enough to get into knock unless boost is limited by the TM settings or by the wastegate duty cycle.

My pressure delta is basically stock. A little higher at 6900 may be helpful. I did not see any advantage from raising it at lower rpms, but I didn't raise it as much as the 1.4 as used in the example.

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I get the Knock Air Mass. My thought for the pressure delta has more to do with WOT downshift response. Lets say you are cruising in 6th gear then you stomp it. I want to boost to respond quickly. I just need to make sure its not too much.

I just added another calculation to the spreadsheet. On the right of the sheet if you type in the kW it will calculate HP and torque at RPM breaks. I use this to make sure that the torque I have entered in the TM>General> Peak/Brake Torque limit/Overboost torque settings are not set too low compared to the Pedal Requested kW in the TM>Engine>Driver Demand table.

Well hello there! Good thread. I am working on "Da Summer" and encountering very similar issues. While it is an LHU, it uses E39A so the control strategy is near identical.

still missing something to keep boost consistent through out the rpm range. I have made a lot of changes but still not right. It is way better but still get a spike then fall off. Some times nail it and pulls great and next time might be totally flat. Any ideas????

Just to be sure, the throttle's not closing on you is it? Have you logged Absolute Throttle position?

Watching throttle on the gauges is stays at 84 percent which I was told is wot on hp pretty much the whole time. I did see it dip to 70 on one wor log I did but next one it didn't so not sure if doing it all the time or not. Gonna run another log tonight. I rained and cooled off here so good time to do it will make more power.

Yes about 84% is WOT and that's as per GM if I understand correctly. Mine does the same thing, finally open all the way and the whole time whenever I want it, with just the slightest blink to about 70% occasionally but just for a split second - different & unknown reason. One day I will figure out why, right now there are other things that bother me more.