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  1. #1
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    Cobb ATR timing drop on all runs after a long 4th gear run...out of ideas

    Hi,

    Here is a stupid situation happening to my car (RB FBO 335i 6MT): after I do a long 4-th gear pull (up to 6200+RPM), on all the following pulls my timing is very low, mostly negative. No timing corrections are recorded, and no error codes. The ECU just decides on its own that it should drop the timing Click here to enlarge. Everything fixes itself either after I let the car sit for 1-2 hours, or even after a low-timing run it sometimes fixes itself on other runs but not sure in which conditions.

    Anyone has any idea about this ? I asked Josh@Cobb and he things that the overboost after shift is causing the problem. But I have identical overboost on all the 3rd gear runs before the dreaded 4-th gear run and it doesn't happen.

    In the picture you see a 3-4-5 run with good timing, followed by a 3-4 run with very low timing.

    Anyone has any idea about this ? I'm starting to give up on it Click here to enlarge

    Click here to enlarge

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    I can't comment on the Cobb only tuning but if you get bored borrow a G5 ISO and you can try out our back end flash with it. Our "pump gas" map runs similar advance to what you have in that log up there.
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    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

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    Interesting, this timing flatline happens in 5th usually. Josh is actually right about you overshooting post shift causing the issue it also happens if you were to load the gear without the shift.

    I'd also consider stacking a JB4 in this situation. The dummy feed from the piggyback is always less than the set point so it would resolve this particular issue

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    Click here to enlarge Originally Posted by themyst Click here to enlarge
    The dummy feed from the piggyback is always less than the set point so it would resolve this particular issue
    No it's not. Click here to enlarge Only if boost is under or on target is it less than the SP.
    Burger Motorsports
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    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

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    Can you post a csv with the default logging channels where this happens?
    Click here to enlarge
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    Cobb only knowhow is not strong in the forum. Terry is your best bet for tuning, great customer service and help.

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    Click here to enlarge Originally Posted by rader1 Click here to enlarge
    Can you post a csv with the default logging channels where this happens?
    CSV posted on this post.

    Click here to enlarge Originally Posted by Terry@BMS Click here to enlarge
    I can't comment on the Cobb only tuning but if you get bored borrow a G5 ISO and you can try out our back end flash with it. Our "pump gas" map runs similar advance to what you have in that log up there.
    I'm sorry but I am not a believer in piggybacks when the ability to directly work with the ECU is already here. I am sure the JB4 has the ability to fix this, but this is not the kind of help I wanted on this issue.

    Click here to enlarge Originally Posted by themyst Click here to enlarge
    Interesting, this timing flatline happens in 5th usually. Josh is actually right about you overshooting post shift causing the issue it also happens if you were to load the gear without the shift.
    It doesn't seem to be a flatline to me. It's a climbing line very similar to the correct line, but offset by 9-10 degrees.

    What's strange is that by any book, a short overshoot of a PID system is deemed to be ok and beneficial. The current boost curves look like a critically damped PID system. I am sure BMW thought the same when they designed the boost control system.

    This being said, my plans are:

    - My ECU OEM software is 2 years old. I will do a software update and see if there are any improvements.

    - I will also modify the WGDC P-factor table to hopefully cut the post-shift overboost (I have already modified the D-factor and I-factor and I think I got good results on fixing oscillations and damping the boost curve). But right now there are some problems in ATR which prevent the correct modification of the P-factor table, hopefully Josh will send me the "fix" soon.
    Attached Files Attached Files
    Last edited by cstavaru; 03-05-2013 at 05:01 AM.

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    Have you tried adjusting any of the torque limit tables in Cobb?

    i have a simalar issue with an AT.

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    Only heard about this issue on 6AT cars (mine included). Weird.
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    Click here to enlarge Originally Posted by cstavaru Click here to enlarge
    CSV posted on this post.



    I'm sorry but I am not a believer in piggybacks when the ability to directly work with the ECU is already here. I am sure the JB4 has the ability to fix this, but this is not the kind of help I wanted on this issue.



    It doesn't seem to be a flatline to me. It's a climbing line very similar to the correct line, but offset by 9-10 degrees.

    What's strange is that by any book, a short overshoot of a PID system is deemed to be ok and beneficial. The current boost curves look like a critically damped PID system. I am sure BMW thought the same when they designed the boost control system.

    This being said, my plans are:

    - My ECU OEM software is 2 years old. I will do a software update and see if there are any improvements.

    - I will also modify the WGDC P-factor table to hopefully cut the post-shift overboost (I have already modified the D-factor and I-factor and I think I got good results on fixing oscillations and damping the boost curve). But right now there are some problems in ATR which prevent the correct modification of the P-factor table, hopefully Josh will send me the "fix" soon.
    Running -3 degrees of timing is what we consider a flatline since you are so far off the set point.

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    Click here to enlarge Originally Posted by Jetbill Click here to enlarge
    Have you tried adjusting any of the torque limit tables in Cobb?
    No but thanks for the idea ! Josh@Cobb also recommended to check the "Disable torque intervention by ign" flag in maps, maybe if I check this the torque limiting maps are skipped ? I am a bit afraid of checking that flag because of ESP/DTC reasons. I mean, what happens when the ESP/DSC needs to limit torque ? Does this flag prevent it ?

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    Click here to enlarge Originally Posted by cstavaru Click here to enlarge
    I'm sorry but I am not a believer in piggybacks when the ability to directly work with the ECU is already here. I am sure the JB4 has the ability to fix this, but this is not the kind of help I wanted on this issue.
    No offense taken. Hopefully you can figure it out. But, from what I've seen so far, there are missing tables in the flash preventing complete control over timing. We've had to make various flash changes in such a way to work around these missing tables.
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    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

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    Click here to enlarge Originally Posted by Terry@BMS Click here to enlarge
    No offense taken. Hopefully you can figure it out. But, from what I've seen so far, there are missing tables in the flash preventing complete control over timing. We've had to make various flash changes in such a way to work around these missing tables.
    Heh as someone whos wrestled with doing things flash only, you're spending more time trying to get the car to run correctly instead of dialing things in.

    My opinion may change when they fix all these nagging issues, but I prefer the no fuss approach. Click here to enlarge

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    Cobb Post Shift Timing Drops

    Just tried making some changes to the torque limit tables and had no effect. (Boost Limit Mult inc to 2.8 on 310 328, torque limit offest to 410)

    I have done hundreads of logs with the torque intervention disabled and it does nothing.

    Here's 3 of my logs just back to back, DTC off - Stage 1 FMIC agressive slighly modded map. You will see timing drops post shift down to negative 15-20 degress.

    These logs are with the new Alpina AT update as well.

    It should be about time Cobb has a solution that doesnt require accessing a Protuner for a fix..Click here to enlarge
    Click here to enlarge

    I'm going back to JB4.

    Click here to enlarge Originally Posted by cstavaru Click here to enlarge
    No but thanks for the idea ! Josh@Cobb also recommended to check the "Disable torque intervention by ign" flag in maps, maybe if I check this the torque limiting maps are skipped ? I am a bit afraid of checking that flag because of ESP/DTC reasons. I mean, what happens when the ESP/DSC needs to limit torque ? Does this flag prevent it ?
    Attached Files Attached Files

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    PROBLEM SOLVED. I am bit embarrased Click here to enlarge I did all the tests with the DTC button as default. When the problem is present (pressing the pedal in 3rd results in negative boost), as soon as you press the DTC button, the timing is correct. As soon as you set it as default, the timing becomes negative. This happens only after the long 4th gear pull. Before the pull, everything works correctly even with the DTC button as default.

    It's probably a bug either in Cobb or in the OEM software. But I don't care, if I press the DTC everything works correctly time after time Click here to enlarge

    Below is a graph to see how it works. When the PEDAL is at 100, I am doing the test. Between tests (when the pedal is not at max), I toggle the DTC button. You see how the timing alternates between "right" and "wrong" (it's wrong-right-wrong-right-wrong).

    So at least in my case, the problem is solved.

    PS: I also did two maps, one with "Disable torque intervention by ign" checked and one with increased torque limits. No change, the problem still remains (if you run with DTC button as default).
    Attached Images Attached Images  
    Last edited by cstavaru; 03-05-2013 at 03:33 PM.

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    Big turbos, high boost, shift! Boost spike because your DV's are slow, or too small possibly? Maybe not

    Edit- I see it's solved. Always hated DTC

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    Another interesting development: looking at the logs, I see that the parameter "Torque Limit Active" which I logged is "1" when timing is negative, and "0" when timing is correct. This pretty much explains everything. It's some kind of torque limit which I did not find the means to deactivate (yet) - even when checking the "disable torque intervention by ign". I see that the Torque Requested is always 510 (strange - maybe a Cobb hardcoded value ?) and Torque Output varies, being quite high at times, like 780Nm Click here to enlarge

    Although I have increased the torque limit values by 100Nm in the "Load to Torque Limit" table, the values are still too small and should be increased more in order to put the limits over the "Actual Torque" for each combination of RPM and load. I will try to increase these values even more to see if the problem can be fixed even with DTC button at the default value.

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    Click here to enlarge Originally Posted by Jetbill Click here to enlarge
    Just tried making some changes to the torque limit tables and had no effect. (Boost Limit Mult inc to 2.8 on 310 328, torque limit offest to 410)

    I have done hundreads of logs with the torque intervention disabled and it does nothing.

    Here's 3 of my logs just back to back, DTC off - Stage 1 FMIC agressive slighly modded map. You will see timing drops post shift down to negative 15-20 degress.

    These logs are with the new Alpina AT update as well.

    It should be about time Cobb has a solution that doesnt require accessing a Protuner for a fix..Click here to enlarge
    Click here to enlarge

    I'm going back to JB4.
    You're knocking post shift actually. This is not "the" flatline 6AT people usually talk about. DME is pulling timing through timing "corrections" and not pulling out "targetted" timing.
    Click here to enlarge

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    Click here to enlarge Originally Posted by cstavaru Click here to enlarge
    PROBLEM SOLVED. I am bit embarrased Click here to enlarge I did all the tests with the DTC button as default. When the problem is present (pressing the pedal in 3rd results in negative boost), as soon as you press the DTC button, the timing is correct. As soon as you set it as default, the timing becomes negative. This happens only after the long 4th gear pull. Before the pull, everything works correctly even with the DTC button as default.

    It's probably a bug either in Cobb or in the OEM software. But I don't care, if I press the DTC everything works correctly time after time Click here to enlarge

    Below is a graph to see how it works. When the PEDAL is at 100, I am doing the test. Between tests (when the pedal is not at max), I toggle the DTC button. You see how the timing alternates between "right" and "wrong" (it's wrong-right-wrong-right-wrong).

    So at least in my case, the problem is solved.

    PS: I also did two maps, one with "Disable torque intervention by ign" checked and one with increased torque limits. No change, the problem still remains (if you run with DTC button as default).
    No need to be embarrassed. Its a learning process and takes time. This is exactly what I was talking about when it comes to ATR. Just keep at it and most things will eventually be a lot clearer. Datalogging with traction control enabled will almost always screw up timing.

    By the way, you'll still benefit from "Disable Torque Intervention by Ignition" given you're a 6MT. I'd check it off to disable it. If you don't you'll end up wondering sometimes why your target timing is dropping 1-3deg below where you map is set when theres no corrections. It won't go negative as in the case of torque limit active but it'll drop slightly causing noticeable power drops. It helps on 6ATs too but it causes fairly rough shifts so there I'd leave it unchecked but maybe someone could argue that under the covers transmission line pressure is raised LOL
    Last edited by dzenno@PTF; 03-05-2013 at 07:40 PM.
    Click here to enlarge

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    Click here to enlarge Originally Posted by cstavaru Click here to enlarge
    Another interesting development: looking at the logs, I see that the parameter "Torque Limit Active" which I logged is "1" when timing is negative, and "0" when timing is correct. This pretty much explains everything. It's some kind of torque limit which I did not find the means to deactivate (yet) - even when checking the "disable torque intervention by ign". I see that the Torque Requested is always 510 (strange - maybe a Cobb hardcoded value ?) and Torque Output varies, being quite high at times, like 780Nm Click here to enlarge

    Although I have increased the torque limit values by 100Nm in the "Load to Torque Limit" table, the values are still too small and should be increased more in order to put the limits over the "Actual Torque" for each combination of RPM and load. I will try to increase these values even more to see if the problem can be fixed even with DTC button at the default value.
    I brought up the torque limit active channel when it came to flatlines on the 6ATs just a couple days back. Cobb added it when we were troubleshooting flatlines which made us realize the TCU was the most likely culprit for sending back messages to the DME to limit torque causing timing dropouts and oscillations mid pull, making the car feel like it was cutting out under WOT. Torque Limit Active would go from zero to 4 in that case. Zero means torque limit isn't active basically.
    Click here to enlarge

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    Click here to enlarge Originally Posted by dzenno@ProTUNING Freaks Click here to enlarge
    By the way, you'll still benefit from "Disable Torque Intervention by Ignition" given you're a 6MT. I'd check it off to disable it. If you don't you'll end up wondering sometimes why your target timing is dropping 1-3deg below where you map is set when theres no corrections.
    Thank you dzenno for chiming in Click here to enlarge Not sure what the "disable torque intervention by ign does". Will this improve the post-shift behaviour on 6MT cars ? I don't want to shut off a useful protection, if it is something like this. I would prefer to increase the values in the load limit tables, hoping that the torque intervention would have no reason to activate because the torque limits are high enough. But I guess it's better to be safe so I may just check that...however it would be of great benefit if someone (maybe you ?) could explain in what situations the ECU reduces torque by timing retard.

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    Load control and its insane internal modeling Click here to enlarge i wouldn't worry disabling it on a 6mt..traction control will do its job, try it Click here to enlarge
    Click here to enlarge

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    Click here to enlarge Originally Posted by Jetbill Click here to enlarge
    It should be about time Cobb has a solution that doesnt require accessing a Protuner for a fix..Click here to enlarge
    I can help you with some things related to the timing corrections (not the drop after shift - I think they are not related anyway). You just have to have ATR installed and working on your computer. Just send me a PM with your email address.

    Also log the "Torque Limit Active" parameter, see if there are any non-zero values on your log.

    I can send you a map with raised torque limits, maybe it can help.

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    Click here to enlarge Originally Posted by dzenno@ProTUNING Freaks Click here to enlarge
    You're knocking post shift actually. This is not "the" flatline 6AT people usually talk about. DME is pulling timing through timing "corrections" and not pulling out "targetted" timing.
    Any suggestions to fix it? It didn't seem that evident. Thanks.

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    So from my understanding even when running only Stage 1 sport on the Cobb (91 octane oblige) I should deactivate the torque intervention by ign on my 6MT because it's better ? Also is better with xi ? Wondering because from time to time I have this strange surging like feeling without nothing special showing on the datalogs

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