Results 1 to 17 of 17

Thread: supercharged GPEC2 SRT8 hidden fuel cut/torque limiter table?

  1. #1
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19

    Unhappy supercharged GPEC2 SRT8 hidden fuel cut/torque limiter table?

    Howdy all,

    I hope you don't mind me reaching out for a helping hand, as I'm at my wit's end here. I'm in the process of tuning a cammed Procharged 6.4L SRT8 Challenger with with built motor, 3-bar MAP sensor and I like to think that the tune is close to completion with no issues except the following. At 3000ft elevation, it hits ~195-200kpa @ redline without issue, however down at sea level, where I see the same boost @ approximately 5800rpm it hits some sort of limiter and refuses to rev any higher. Now I have all the torque limiters and torque management nannies maxed out and have absolutely no idea what could be causing this. NN and VVT are disabled/locked-out and I'm using the VE tables to tune. Any ideas what's going on here?

    I have attached the tune in question, along with logs @ elevation without issue and on the dyno (where the problem manifests itself)
    Please advise, thank you!
    Last edited by Hydra Performance; 04-28-2022 at 11:50 PM.

  2. #2
    Advanced Tuner N2speed's Avatar
    Join Date
    Mar 2021
    Location
    Pompano Beach FL
    Posts
    249
    I will take a look. Do you have the stock read as well?


    www.n2speed.com
    http://www.amp4x4.com
    [email protected]

    Dodge And GM Tuning Suppport
    Diablosport CMR | HP Tuners

  3. #3
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quote Originally Posted by N2speed View Post
    I will take a look. Do you have the stock read as well?


    Thanks a million! Yes, I do


    elie abdayem 392 hemi challenger base.hpt

  4. #4
    Senior Tuner SultanHassanMasTuning's Avatar
    Join Date
    Nov 2009
    Location
    All Around
    Posts
    3,149
    elie abdayem 392 hemi challenger hydra 3BAR 80lb v7_test.hpt

    you need to log better channels

    fuel source spark source

    all limits

    also spark control under fuel cutt seems disabled
    Follow @MASTUNING visit www.mastuned.com
    Remote Tuning [email protected]
    Contact/Whatsapp +966555366161

  5. #5
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quote Originally Posted by SultanHassanMasTuning View Post
    elie abdayem 392 hemi challenger hydra 3BAR 80lb v7_test.hpt

    you need to log better channels

    fuel source spark source

    all limits

    also spark control under fuel cutt seems disabled
    Yeah FWIW I logged throttle torque source in a later datalog (which unfortunately I did not save) and it remained @ "Pedal" throughout, despite the early cutoff (where you can obviously see the throttle closing)

    I will try again and get back to you ASAP, thank you very much for your assistance

  6. #6
    Advanced Tuner
    Join Date
    Oct 2005
    Location
    baton rouge la
    Posts
    411
    Quote Originally Posted by Hydra Performance View Post
    Howdy all,

    I hope you don't mind me reaching out for a helping hand, as I'm at my wit's end here. I'm in the process of tuning a cammed Procharged 6.4L SRT8 Challenger with with built motor, 3-bar MAP sensor and I like to think that the tune is close to completion with no issues except the following. At 3000ft elevation, it hits ~195-200kpa @ redline without issue, however down at sea level, where I see the same boost @ approximately 5800rpm it hits some sort of limiter and refuses to rev any higher. Now I have all the torque limiters and torque management nannies maxed out and have absolutely no idea what could be causing this. NN and VVT are disabled/locked-out and I'm using the VE tables to tune. Any ideas what's going on here?

    I have attached the tune in question, along with logs @ elevation without issue and on the dyno (where the problem manifests itself)
    Please advise, thank you!



    Attachment 119221
    Attachment 119222
    Attachment 119223
    One thing that jumped out at me in the "arabi7" log is the ECT. Looks like the sensor failed and is reading -78*F I had a GC give me some fits a week ago, and it seemed the culprit was the ECT sensor. The jeep ran great until it got to operating temp. When it did, the sensor failed, and the gauge on the dash went to the bottom. The log would start reading correct again but the display on the dash would not. Once I swapped that sensor everything cleared up

  7. #7
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quote Originally Posted by white1 View Post
    One thing that jumped out at me in the "arabi7" log is the ECT. Looks like the sensor failed and is reading -78*F I had a GC give me some fits a week ago, and it seemed the culprit was the ECT sensor. The jeep ran great until it got to operating temp. When it did, the sensor failed, and the gauge on the dash went to the bottom. The log would start reading correct again but the display on the dash would not. Once I swapped that sensor everything cleared up
    What I found very unusual was that the indicated (graphical) ECT and IAT readings on the dash you see are not the same as the textual ECT & IAT values you see on the left half of the VCM Scanner. Didn't really bother figuring out the reason for the discrepancy as the text values appear normal.

  8. #8
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quick update for you guys. I performed all the suggested modifications to the tune and tried again. Still the same no change... It would appear as though its cuts out @ exactly 200kPA which leads me to believe that this may be something hardcoded in the OS? I have attached a copy of the latest tune & a few sea-level logs, both with and without the air filter attached. When the air filter is removed it cuts out approx 250rpm sooner but also very close to the 200kPa boost ceiling. Please advise :/



    elie abdayem 392 hemi challenger hydra 3BAR 80lb v9.hpt
    dodge dyno3 no filter.hpl
    dodge coastal hwy1.hpl
    dodge coastal hwy2.hpl
    Last edited by Hydra Performance; 04-20-2022 at 04:51 PM.

  9. #9
    So I'm not 100% on this, but I've been told and have heard that for the 09-14 gpec2a ecu's they do not handle boost levels above 200 kpa ~ 15 psi of boost. If this is the case the hack for this is to any tuning above 200 kpa as if it were 200 kpa. I have a 13 Challenger R/t with GPEC2a ecu, and I'm getting tuned tomorrow. I'll report back if I run into this issue on the dyno as well. I also have a 3 bar map, so many of the mods are the similar.

  10. #10
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quote Originally Posted by DakBuilder View Post
    So I'm not 100% on this, but I've been told and have heard that for the 09-14 gpec2a ecu's they do not handle boost levels above 200 kpa ~ 15 psi of boost. If this is the case the hack for this is to any tuning above 200 kpa as if it were 200 kpa. I have a 13 Challenger R/t with GPEC2a ecu, and I'm getting tuned tomorrow. I'll report back if I run into this issue on the dyno as well. I also have a 3 bar map, so many of the mods are the similar.
    What's happening here is that its simply cutting out/hitting an early rev-limit, making further tuning impossibru. What I might do, if there is no other choice, is to rescale the MAP sensor and all the affected load tables so that it reads 200kPa say @ an actual 250kPa instead...

  11. #11
    bored on my lunch break , did not review file but i would say put max map for 195 kpa
    have a good day

  12. #12
    Just wanted to report back, my tune was cleaned up by a tuner. I had some bad data put into the injector scaling. That cleaned up a lot of my issues. I'll get into the boost limit issues here soon

  13. #13
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Just wanted to report back myself, putting max map @ 197kPa solved the issue and all is good now!

  14. #14
    Advanced Tuner f.creek-ranch's Avatar
    Join Date
    May 2018
    Location
    Germany
    Posts
    572
    did you measure the real kpa externally? Would be interesting.

  15. #15
    Tuner in Training Hydra Performance's Avatar
    Join Date
    Jul 2020
    Location
    +961
    Posts
    19
    Quote Originally Posted by f.creek-ranch View Post
    did you measure the real kpa externally? Would be interesting.
    Not yet, delivered the car to the customer. Will definitely be doing this next time around @ the next round of mods

  16. #16
    Quote Originally Posted by Team_hellcat View Post
    bored on my lunch break , did not review file but i would say put max map for 195 kpa
    have a good day

    Why is setting the max KPA to 195 the solution? I'm good with inputting those values, but I like to understand what is actually happening.

  17. #17
    Advanced Tuner coanan's Avatar
    Join Date
    Mar 2009
    Location
    S. Florida
    Posts
    582
    Quote Originally Posted by DakBuilder View Post
    Why is setting the max KPA to 195 the solution? I'm good with inputting those values, but I like to understand what is actually happening.
    Did you ever figure this out? Going thru the same thing with my Whipple build.
    2018 Trackhawk PCM/TCM tune by Dusterhoff.
    Flex Fuel, MMX faux 95mm TB, GripTec 2.85, 10% ATI lower, FIC1200, ARH 1 7/8 w/cats, 180 T-stat

    13 Chrysler 300S, RAM BGE 412 stroker, cam motion 232/246 619/619 118 +4, ATI 18% OD pulley
    Whipple Gen5 3.0, 2.50 upper pulley, Smooth Boost controller, FIC 1200 inj. Nick W 108mm TB, FORE dual return fuel system, E85, FTI 2800 stall(SRT83380), SHR WAR Viking trans and valve body, Getrag 3.73, 1 7/8 kooks w/hi-flow cats, 3" Magnaflow Cat-back 943rwhp