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Thread: What limit am i hitting its not showing up in log

  1. #1

    What limit am i hitting its not showing up in log

    2015 Mustang GT with a single 80mm turbo, 2018 intake, IMRC Deleted. Car runs fine on the street but at the track sometimes it will close the throttle completely and if you raise you foot off the pedal and press it back down the car will take back off, sometimes we are able to complete a full pass without it shutting down last week it did 5 back to back passes with hardly any cool down with no issues First pass off the trailer this past weekend we got the dead pedal again. I have tried adjust max map delta vs BP I even set it to all 0 and made successful passes so I don't think that table is closing the throttle any help would be appreciated. see attached log and tune file.tune with no dead pedal 18 psi.hpt-dead pedal bg1.hpl

  2. #2
    Senior Tuner veeefour's Avatar
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    That's a problem related to turbo Joe, and its hard to solve - at part throttle boost goes up and this is where your ETC torque is lets say 400Nm and your Brake Torque is 800Nm.
    ECU see twice the torque that is commanded and it will goes nuts closing the throttle. That's why turbo cars are equipped with MAP from factory.
    Last edited by veeefour; 08-20-2019 at 01:23 AM.

  3. #3
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    Your torque control is not happy. Like its stuck on the low range DD table. Something you changed under torque management either under engine or transmission is causing this limit. Being under your IPC torque minimum, its the only thing helping you at this point.

    TQ low range.PNG

    You can also improve the SD to resemble your boost sensor. Its not registering vacuum so you can only do so much with it to correct SD.

    SD adjust from AEM .PNG

    Unless you are trying to run 30 PSI of boost I would lower the max calculated MAP to 35 psi. I was just going off what little the sensor was telling me. The general rule to this is above 14psi(~baro) you want load to either go flat or drop as RPM goes up. This helps steady the ETC vacuum and prevent the throttle from closing its self.

    Chart from AEM .PNG

    Once your calculated MAP goes above baro, any drop in it like you have in this log comes out of the vacuum in the TB model. Stuff like this at partial throttle causes surge and bad throttle control.

    The goal is to get calculated map and your actual map looking the same. Besides being a little high from 3000-4500 it looks pretty close at WOT.
    Last edited by murfie; 08-20-2019 at 04:23 AM.

  4. #4
    I’m trying to run around 18 psi of boost the pressure sensor I was using was mounted in the charge pipe right before throttle body i since moved it to the intake behind TB so I can get a accurate reading along with vacuum.

    Any idea what I can do to fix the issue. It just closes the throttle at the track and sometimes it will make a complete pass with no issues. What torque management areas do you think I should adjust to fix the issue?

  5. #5
    Murfie since I moved my pressure sensor behind the TB now I can see vacuum and boost however if I use the speed density calculator in hp tuners I just see boost pressure why would I need to see vacuum? I've never dialed in speed density before and looking at the calculator I see psi on Y axis and Rpm on X axis is the information in the cells load? Would I create a histogram with air load and RPM and fill in my cells with boost pressure, how would you go about doing it?

    I assume once I get the Speed Density dialed in then that will help with bringing the Calculated Map and actual inline or will this just help with fueling?

  6. #6
    Any ideas on how to solve or any guidance you can give me

  7. #7
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    Quote Originally Posted by Eleazer2 View Post
    Murfie since I moved my pressure sensor behind the TB now I can see vacuum and boost however if I use the speed density calculator in hp tuners I just see boost pressure why would I need to see vacuum? I've never dialed in speed density before and looking at the calculator I see psi on Y axis and Rpm on X axis is the information in the cells load? Would I create a histogram with air load and RPM and fill in my cells with boost pressure, how would you go about doing it?

    I assume once I get the Speed Density dialed in then that will help with bringing the Calculated Map and actual inline or will this just help with fueling?
    The row axis is pressure in an absolute scale, so "vacuum" is 14.7psi or less. The HPT predefined senor PID you are using is offset to 1 atmosphere, you have to undo that to get it back on the absolute scale and only get positive values.

    It can help with fuel, it can also help with the TB model vacuum.

    I would first raise your "load at WOT" table and see if the ETC torque comes up closer to engine brake torque.

  8. #8
    Quote Originally Posted by murfie View Post
    The row axis is pressure in an absolute scale, so "vacuum" is 14.7psi or less. The HPT predefined senor PID you are using is offset to 1 atmosphere, you have to undo that to get it back on the absolute scale and only get positive values.

    It can help with fuel, it can also help with the TB model vacuum.

    I would first raise your "load at WOT" table and see if the ETC torque comes up closer to engine brake torque.
    Murfie can you tell me how I can adjust the sensor so I can make it read absolute the formula it comes predefined with shows (V/0.08) =+ -20.95=output psi


    I actually had load at WOT set to air load values on completed runs however I was still getting the dead pedal so as a recommendation we lowered the values back to stock to see if it was something in the speed density section causing the throttle closure issue.

  9. #9
    if I'm thinking right would I just create a math function and do aem pressure sensor + 14.7

  10. #10
    Senior Tuner veeefour's Avatar
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    Quote Originally Posted by Eleazer2 View Post
    if I'm thinking right would I just create a math function and do aem pressure sensor + 14.7
    That's the way to do this.

  11. #11
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    You can add 14.7 to the predefined PID or:

    https://www.aemelectronics.com/files...sor%20Data.pdf

    If it really is the sensor you choose the predefined function for, you would just log the voltage directly from it and multiply it by 12.5 and subtract 6.25. Its a simple linear scale voltage to absolute PSI.

  12. #12
    Thanks guys any ideas on the Torque management issues you think that is causing the problems with the ETC torque request being so low?

  13. #13
    May be having minor issues around this as well. Not having any issues of throttle closing but a little hiccup with IPC right around bypass closing and building a little boost around transition. Seems to be definitely a relationship to ETC torque vs EBT. All though my DD is commanding a higher TQ at times it doesn't want to grab itIPC error.JPG. Not sure what is leaving it in a lower TQ demand even though in DDemand. Anyone know how the IPC TQ Max and minimum work. If they are ceiling and floor. I'm assuming ceiling higher than capable TQ. Floor initial thought lower than ever would happen. Or do you also increase minimum table to hug actual TQ. As to narrow bandwith. Have no idea what the calculation is with IPC error.

  14. #14
    Ok I think I got the throttle issues solved I can see ETC torque requesting more now however I am now hitting a throttle angle source limit TQ Reduction Driver demand it seems to hit it every time my etc torque request hits 738 ft lbs. what is causing this limit. I attached a screen shot of the DD table and Torque table im running in along with a log if the run.good pass hill last 6.88.hplDD and MP 15.PNG