Page 1 of 3 123 LastLast
Results 1 to 20 of 45

Thread: Stomp Compensation tables

  1. #1
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242

    Stomp Compensation tables

    Hey guys...I've done all searches and read every thread on the forum regarding Transient fuel tables and using the Stomp Compensation to eliminate a slight off idle hesitation I can't seem to get rid of.
    Car is a 07C6Z06Twin Turbo M6. I'm using a MAF tune(Abaco) and runs great except for this problem. When cruising at low RPM(1200-1800) at about 10% or less throttle, when I let off the gas and ease back on it the car hesitates and my AFR's jump to 16.0 for a moment before picking back up. No timing drop along with the hesitation just lean condition.

    I would like to try adding to the Base Gain or Stomp Compensation but not sure what values to start with as my table is zero'd out.
    Does anybody have any experience with this table and a possible starting point to populate it? I gather from other threads on the topic that it has the ability to impact fueling more than just at warmup.
    Last edited by ttz06vette; 05-21-2010 at 10:21 AM. Reason: spelling error

  2. #2
    Advanced Tuner
    Join Date
    Jul 2009
    Posts
    509
    Subscribing.
    2016 GMC Sierra 1500 6.2L

  3. #3
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    No one has had experience with these tables or has them populated with data?

  4. #4
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    Final Bump...anyone?

  5. #5
    Senior Tuner Frost's Avatar
    Join Date
    Jan 2006
    Location
    Richmond VA
    Posts
    1,950
    Are you sure that this is the issue and it's not an injector short-pulse problem? If minimum pulse isn't obtained through the VE/MAF (the trims fight it fight it down), it will cause a lean spot as you transition into throttle even lightly.
    Steve Williams
    TunedbyFrost.com


  6. #6
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    Quote Originally Posted by Frost View Post
    Are you sure that this is the issue and it's not an injector short-pulse problem? If minimum pulse isn't obtained through the VE/MAF (the trims fight it fight it down), it will cause a lean spot as you transition into throttle even lightly.
    Thanks for your reply.
    My average STFT/LTFT's look pretty good and if I keep the RPM's up I don't have the problem. But if cruising or shifting at low RPM's(<2000) the car will hesitate for a second and my AFR's will spike to above 16.0 then settle back to stoich.
    I have a custom 16 injector sheetmetal intake manifold on the car and I was thinking maybe heat soak was the culprit potentially causing the transient fuel settings to be off due to quicker evaporation of fuel from the walls. I thought if the stomp compensation tables truly act like an "accelerator pump" I might be able to just use the table to richen transient shot at the problem point. Just not sure where to start.

  7. #7
    Senior Tuner Frost's Avatar
    Join Date
    Jan 2006
    Location
    Richmond VA
    Posts
    1,950
    The stomp comp table is overly rich from the factory and really only covers fast heavy throttle. If your problem is present is on every transition from closed throttle it's more than likely (although nothing that we can be sure of with no logs of the event) short pulse related.
    Steve Williams
    TunedbyFrost.com


  8. #8
    Tuner in Training
    Join Date
    Dec 2008
    Posts
    48
    From my experience with e38 this is typical of a MAF tune with fast throttle movement more so when the VE table is incorrect, ie lean in that area. Disable VE and try it.

  9. #9
    Tuner
    Join Date
    Feb 2007
    Location
    Calgary
    Posts
    155
    Quote Originally Posted by Frost View Post
    Are you sure that this is the issue and it's not an injector short-pulse problem? If minimum pulse isn't obtained through the VE/MAF (the trims fight it fight it down), it will cause a lean spot as you transition into throttle even lightly.
    Could you explain this a little more thoroughly?

  10. #10
    Tuner in Training
    Join Date
    Dec 2008
    Posts
    48
    If its any help Generally you leave transients stock with e38s with a MAF tune, Dont touch them to mask the ve table being incorrect.

    In SD it is different. The e38 relies on the maf to function for the transients to function correctly. So they have to be modified, Also the MAF responds faster then the MAP does with the e38, In the case of a straight SD tune raise the multiplier at 0g/s in the transient fueling to 0.8 then increase the impact to around .280. Anymore then this is to much, then it is a matter of raising the stomp compensation until it feels crisp on the throttle(after steady state fuelling is dialled in of course) Since the map responds slower it requires the stomp compensation to be increased then they feel great. Years ago I always made the mistake of increasing the impact to high to mask lean spots and I realised then the impact was always right. It was just a matter of making sure the multiplier was set correctly(.8) at 0g/s then using the stomp table to assist in helping the lean spot from slower map calcs. In the case of increasing it with the MAF in place all it will do is overfuel it as the MAF table already does a great job of fast throttle movement-It tips in enough fuel as is. I would look into the VE table side of things. OR disable high speed airflow calcs. If you don't have a 2.5bar cos install it and do the ve table in steady state looking at the areas you mention. It should not be an issue at all. Some tuners think that the ve does nothing with the MAF on but this is b/s, it improves drivability immensely. To be honest I would rather do a SD tune I can do them quicker!
    Last edited by hymey; 09-15-2010 at 04:03 AM.

  11. #11
    Tuner
    Join Date
    Feb 2007
    Location
    Calgary
    Posts
    155
    Quote Originally Posted by hymey View Post
    If its any help Generally you leave transients stock with e38s with a MAF tune, Dont touch them to mask the ve table being incorrect.

    In SD it is different. The e38 relies on the maf to function for the transients to function correctly. So they have to be modified, Also the MAF responds faster then the MAP does with the e38, In the case of a straight SD tune raise the multiplier at 0g/s in the transient fueling to 0.8 then increase the impact to around .280. Anymore then this is to much, then it is a matter of raising the stomp compensation until it feels crisp on the throttle(after steady state fuelling is dialled in of course) Since the map responds slower it requires the stomp compensation to be increased then they feel great. Years ago I always made the mistake of increasing the impact to high to mask lean spots and I realised then the impact was always right. It was just a matter of making sure the multiplier was set correctly(.8) at 0g/s then using the stomp table to assist in helping the lean spot from slower map calcs. In the case of increasing it with the MAF in place all it will do is overfuel it as the MAF table already does a great job of fast throttle movement-It tips in enough fuel as is. I would look into the VE table side of things. OR disable high speed airflow calcs. If you don't have a 2.5bar cos install it and do the ve table in steady state looking at the areas you mention. It should not be an issue at all. Some tuners think that the ve does nothing with the MAF on but this is b/s, it improves drivability immensely. To be honest I would rather do a SD tune I can do them quicker!
    Increase impact to .280? I am in the map vs. ivt impact table at 250% across all the columns. Was a big improvement but I'm sure it could be better. Do you mean this table?

  12. #12
    Tuner in Training
    Join Date
    Dec 2008
    Posts
    48
    Quote Originally Posted by backchannel View Post
    Increase impact to .280? I am in the map vs. ivt impact table at 250% across all the columns. Was a big improvement but I'm sure it could be better. Do you mean this table?
    Change the gain to 1.00,

    Then in IVT under 80 and 100kpa set them to 0.280 and see how they feel, it may need to go to 0.300 under 100kpa @over 140 deg IVT, with a multiplier to 1.00.
    Last edited by hymey; 09-22-2010 at 09:28 PM.

  13. #13
    Tuner in Training
    Join Date
    Dec 2008
    Posts
    48
    Please log IVT and see if it is functioning correctly, efilive did a fix for it and ever since I flashed it in to my pcm it has remained permanently correct weather I flash it with vcm or not, but with other cars same o/s that have only been flashed with vcm the ivt values are all screwed up. Should be 160 deg hot.

  14. #14
    Tuner
    Join Date
    Feb 2007
    Location
    Calgary
    Posts
    155
    Quote Originally Posted by hymey View Post
    Please log IVT and see if it is functioning correctly, efilive did a fix for it and ever since I flashed it in to my pcm it has remained permanently correct weather I flash it with vcm or not, but with other cars same o/s that have only been flashed with vcm the ivt values are all screwed up. Should be 160 deg hot.
    I have logged IVT and I will check some of them

    14x cruise 163 max
    Last edited by backchannel; 09-22-2010 at 10:00 PM.

  15. #15
    Tuner in Training
    Join Date
    Apr 2008
    Posts
    27
    Quote Originally Posted by ttz06vette View Post
    Thanks for your reply.
    My average STFT/LTFT's look pretty good and if I keep the RPM's up I don't have the problem. But if cruising or shifting at low RPM's(<2000) the car will hesitate for a second and my AFR's will spike to above 16.0 then settle back to stoich.
    I have a custom 16 injector sheetmetal intake manifold on the car and I was thinking maybe heat soak was the culprit potentially causing the transient fuel settings to be off due to quicker evaporation of fuel from the walls. I thought if the stomp compensation tables truly act like an "accelerator pump" I might be able to just use the table to richen transient shot at the problem point. Just not sure where to start.
    FWIW, I'm having the same issue with my E40 tune on a 05 GTO. I also have an Abaco MAF setup and was wondering if it was something that could be tuned out with the Abaco software rather than in the ECU. I found the following at the end of the instruction manual:

    "Noise threshold values can be adjusted to change how the DBX meter reacts to very quick changes in airflow. The DBX processor will allow a very large, rapid change in airflow input value to “bypass” the smoothing process assuming that it is due to a “real” condition such as fast throttle movement. If very large, fast changes were averaged into the rest of the output samples, it would be likely to cause a lean throttle “tip in” problem. If lean air/fuel mixtures are seen during rapid throttle application, the Noise Threshold value can be lowered to allow for smaller dynamic airflow changes to bypass the averaging process. Noise Threshold values may be altered by typing a new number directly into the “Noise Threshold “value box or using the up and down arrows provided in the “Advanced” window. The default value of 3 should be used unless reliable data suggests otherwise."

    How did you end up solving the problem?

  16. #16
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    Quote Originally Posted by JoshMass View Post
    FWIW, I'm having the same issue with my E40 tune on a 05 GTO. I also have an Abaco MAF setup and was wondering if it was something that could be tuned out with the Abaco software rather than in the ECU. I found the following at the end of the instruction manual:

    "Noise threshold values can be adjusted to change how the DBX meter reacts to very quick changes in airflow. The DBX processor will allow a very large, rapid change in airflow input value to “bypass” the smoothing process assuming that it is due to a “real” condition such as fast throttle movement. If very large, fast changes were averaged into the rest of the output samples, it would be likely to cause a lean throttle “tip in” problem. If lean air/fuel mixtures are seen during rapid throttle application, the Noise Threshold value can be lowered to allow for smaller dynamic airflow changes to bypass the averaging process. Noise Threshold values may be altered by typing a new number directly into the “Noise Threshold “value box or using the up and down arrows provided in the “Advanced” window. The default value of 3 should be used unless reliable data suggests otherwise."

    How did you end up solving the problem?
    Dropped the noise threshold to "1" on the DBX and added 25% to my transient mass gain impact tables from 20-50 MAP range and 104 - 421 degree IVT. Although this is probably not the most elegant solution, as soon as the car dips lean due to airflow, transient kicks in and compensates. It solved 95% of the problem.
    In effect it is telling the ECM that more fuel is left on the walls in these table areas so add more fuel to compensate.

  17. #17
    Senior Tuner DSteck's Avatar
    Join Date
    Mar 2008
    Location
    St. Louis, MO
    Posts
    4,856
    FWIW, I'm running a stock MAF on my TT C6Z and have zero transient issues even with stock transient fueling tables. My car runs pure MAF too. Your injector data plays a hgue role in it. But really what I'm getting at is just use a GM card MAF and be done!

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!

  18. #18
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    Quote Originally Posted by DSteck View Post
    FWIW, I'm running a stock MAF on my TT C6Z and have zero transient issues even with stock transient fueling tables. My car runs pure MAF too. Your injector data plays a hgue role in it. But really what I'm getting at is just use a GM card MAF and be done!
    I would if I could but I have a problem with the intercooler design used by LPE that causes turbulence in the way the air is presented to the MAF. They joined two inter-coolers together into a plenum at top for cooling. Unfortunately this created a ramp effect going into my MAF.
    I need this MAF to smooth out the signal or the low speed surging is terrible.

  19. #19
    Senior Tuner DSteck's Avatar
    Join Date
    Mar 2008
    Location
    St. Louis, MO
    Posts
    4,856
    Why not just do SD?

    What injectors are you using?

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!

  20. #20
    Advanced Tuner ttz06vette's Avatar
    Join Date
    Sep 2008
    Location
    Charlotte, NC.
    Posts
    242
    Quote Originally Posted by DSteck View Post
    Why not just do SD?

    What injectors are you using?
    cause I'm not that good...

    I'm using 16 stock GM injectors in a LPE in a sheetmetal intake utilizing an extended fuel controller. Run on 8 until i max out duty cycle and then the others kick in.