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Thread: 6-71 blown Hemi going full lean on throttle tip-in

  1. #41
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    carbkit-nickel-9.jpg

    That should fix it.

  2. #42
    Tuner Mattechperf's Avatar
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    Quote Originally Posted by 06300CSRT8 View Post
    Looks like you are getting a really bad lean spike when your mechanical secondary throttle body is opening. This is going to be very hard to tune out, as youll need to create a similar increase to airflow in your Airflow->Electronic Throttle-> Airflow, Small, and Large Range tables.
    Okedoke, I submit this for review by the masses.
    I'm using two stock Hellcat throttle bodies. I took the OEM numbers from the ETC Throttle Body Airflow table of a stock Hellcat tune.
    Then I logged the TPS voltage while manually manipulating my throttle linkage. This gave me voltage at closed, neutral, beginning secondary TB engagement, and then WOT.

    Closed: 0.00 v
    Neutral: 0.22 v
    Secondary: 1.47 v
    WOT: 3.92 v

    The secondary linkage arm's ratio lets both TBs reach WOT together. After some spreadsheet mumbo-jumbo, I used the voltage vs throttle position % (derived from physical movement and not the logged TB % PID) and applied this to the OEM airflow numbers while interpolating the new range since the Hellcat has 15 breakpoints and mine has 14.

    HC TB AIRFLOW
    V g/s
    0.000 0.00
    0.020 3.40
    0.049 4.70
    0.098 7.55
    0.152 10.78
    0.200 14.60
    0.352 29.10
    0.499 48.70
    0.748 95.63
    0.899 128.60
    1.051 164.98
    1.251 217.35
    1.500 289.33
    1.652 338.43
    1.852 412.33
    1.999 467.83
    2.248 556.75
    2.502 661.58
    3.011 830.63
    3.500 922.13
    3.798 1638.38

    Throttle Volts Interpolated TB1 g/s Interpolated TB2 g/s Total Airflow g/s
    0.000 0.00 0.00 0.00
    0.098 7.55 0.00 7.55
    0.200 14.60 0.00 14.60
    0.300 24.13 0.00 24.13
    0.401 35.63 0.00 35.63
    0.499 48.70 0.00 48.70
    0.557 59.74 0.00 59.74
    0.714 89.18 0.00 89.18
    0.870 122.22 0.00 122.22
    1.022 157.93 0.00 157.93
    1.564 309.92 13.78 323.69
    2.028 478.29 116.17 594.45
    2.566 682.71 322.68 1005.38
    3.030 834.29 559.86 1394.15
    3.201 866.31 644.69 1511.00
    3.402 903.83 750.00 1653.83
    3.578 1109.99 1004.55 2114.54
    3.700 1403.54 1343.50 2747.04
    3.750 1523.89 1491.33 3015.22
    3.798 1638.01 1636.26 3274.26

    So, there is all is. File attached for anyone to play with and give some feedback.

    Hellcat Dual TB Airflow Calculation.xlsx

  3. #43
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    Quote Originally Posted by Mattechperf View Post
    Okedoke, I submit this for review by the masses.
    I'm using two stock Hellcat throttle bodies. I took the OEM numbers from the ETC Throttle Body Airflow table of a stock Hellcat tune.
    Then I logged the TPS voltage while manually manipulating my throttle linkage. This gave me voltage at closed, neutral, beginning secondary TB engagement, and then WOT.

    Closed: 0.00 v
    Neutral: 0.22 v
    Secondary: 1.47 v
    WOT: 3.92 v

    The secondary linkage arm's ratio lets both TBs reach WOT together. After some spreadsheet mumbo-jumbo, I used the voltage vs throttle position % (derived from physical movement and not the logged TB % PID) and applied this to the OEM airflow numbers while interpolating the new range since the Hellcat has 15 breakpoints and mine has 14.

    HC TB AIRFLOW
    V g/s
    0.000 0.00
    0.020 3.40
    0.049 4.70
    0.098 7.55
    0.152 10.78
    0.200 14.60
    0.352 29.10
    0.499 48.70
    0.748 95.63
    0.899 128.60
    1.051 164.98
    1.251 217.35
    1.500 289.33
    1.652 338.43
    1.852 412.33
    1.999 467.83
    2.248 556.75
    2.502 661.58
    3.011 830.63
    3.500 922.13
    3.798 1638.38

    Throttle Volts Interpolated TB1 g/s Interpolated TB2 g/s Total Airflow g/s
    0.000 0.00 0.00 0.00
    0.098 7.55 0.00 7.55
    0.200 14.60 0.00 14.60
    0.300 24.13 0.00 24.13
    0.401 35.63 0.00 35.63
    0.499 48.70 0.00 48.70
    0.557 59.74 0.00 59.74
    0.714 89.18 0.00 89.18
    0.870 122.22 0.00 122.22
    1.022 157.93 0.00 157.93
    1.564 309.92 13.78 323.69
    2.028 478.29 116.17 594.45
    2.566 682.71 322.68 1005.38
    3.030 834.29 559.86 1394.15
    3.201 866.31 644.69 1511.00
    3.402 903.83 750.00 1653.83
    3.578 1109.99 1004.55 2114.54
    3.700 1403.54 1343.50 2747.04
    3.750 1523.89 1491.33 3015.22
    3.798 1638.01 1636.26 3274.26

    So, there is all is. File attached for anyone to play with and give some feedback.

    Hellcat Dual TB Airflow Calculation.xlsx
    Are the throttle bodies (at least the primary) still running off of "Drive By Wire", or is it all driven by manual linkage? How about a picture of the linkage and tps setup?

    I am curious, because I can totally see the PCM freaking out if it is not in control of the throttle opening via the DBW system.

  4. #44
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    Quote Originally Posted by spoolboy View Post
    carbkit-nickel-9.jpg

    That should fix it.
    Hahaha! You're not kidding.
    I'm actually working on a parallel engine harness to run a stand alone EFI alongside the OEM stuff. A nice Megasquirt MS3 Pro of Holley Dominator EFI would do nicely.

  5. #45
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    Quote Originally Posted by B00STJUNKY View Post
    Are the throttle bodies (at least the primary) still running off of "Drive By Wire", or is it all driven by manual linkage? How about a picture of the linkage and tps setup?

    I am curious, because I can totally see the PCM freaking out if it is not in control of the throttle opening via the DBW system.
    Yes, the primary TB is DBW like stock and a slide type link bar attaches the two with different ratio arms on each
    Attached Images Attached Images

  6. #46
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    OK, good to know. So, shouldn't be getting any crazy PCM limp modes due to DBW not being hooked up.

    So, I gotta ask. You've had this car running a roots blower since 2016 (I presume it was using the same 6-71 you have now, minus the Aftercooler inside the empty blower housing that you added more recently). From the videos I've watched, it seems as though you didn't have a lean-out issue at throttle tip-in during the filming of those videos. Was something changed recently (other than the aftercooler) that has caused this issue to appear? Or did the issue start after the aftercooler was installed? Or was it the progressive throttle setup that spurred the issue? I wouldn't suspect so, given that you have disabled the secondary TB, and still have the lean-out issue.

    Did you change injectors, maybe?

  7. #47
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    Quote Originally Posted by B00STJUNKY View Post
    OK, good to know. So, shouldn't be getting any crazy PCM limp modes due to DBW not being hooked up.

    So, I gotta ask. You've had this car running a roots blower since 2016 (I presume it was using the same 6-71 you have now, minus the Aftercooler inside the empty blower housing that you added more recently). From the videos I've watched, it seems as though you didn't have a lean-out issue at throttle tip-in during the filming of those videos. Was something changed recently (other than the aftercooler) that has caused this issue to appear? Or did the issue start after the aftercooler was installed? Or was it the progressive throttle setup that spurred the issue? I wouldn't suspect so, given that you have disabled the secondary TB, and still have the lean-out issue.

    Did you change injectors, maybe?
    Most of the videos had my old dual TB setup which used an Ozmo controller to run two DBW in parallel. I had issues with driveability, so I worked on this progressive setup.
    I'm using the same injectors as before. I did rebuild the whole fuel system to a return style with Aeromotive A1000 pump, filters, and boost referenced regulator. One of the first things I checked was fuel pressure, and that's been solid.

    I've relocated the coilpacks from the valve covers to underneath the intake manifold and built custom plug wires. I've checked and double checked those and haven't logged or experienced any misfires.

    51697078_10156865352470535_8238713761628684288_n.jpg

  8. #48
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    Everyone, please don't hate me for this.
    I just realized I left something out of my original post that's pretty damn important to this all.

    So, this is a bit experimental. I have a 4/7 & 2/3 firing order swap in this. The cam was built specifically for it and I built new harnesses for the coilpacks and injectors to route them to the appropriate cylinders.

    Now, that being said, I'm not having any issues with either misfires, crank/cam sensor faults, or other sync problems.
    Since the crank sensor matches the cam sensor (timing gear still installed straight up as normal), and the PCM pinouts are routed to the appropriate cylinders, I see no reason the PCM would freak out over the firing order change. I can't find another sensor input besides the crank/cam that would tell it something has changed.

  9. #49
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    Quote Originally Posted by B00STJUNKY View Post
    Are the throttle bodies (at least the primary) still running off of "Drive By Wire", or is it all driven by manual linkage? How about a picture of the linkage and tps setup?

    I am curious, because I can totally see the PCM freaking out if it is not in control of the throttle opening via the DBW system.
    Also, here's a video showing the progressive linkage in action.

    https://youtu.be/ep8R7gtOI_M

  10. #50
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    I am still not convinced the car will have a similar issue once you actually start to drive it. On many of my setups I tuned, in neutral if say I would put the pedal to 30% and hold it, the rpms would shoot up, fade off, dip, then climb again. Logs showed a lean wave of fuel coming in and out. I was basically teasing the very very far left bottom of the VE table, which you CAN NEVER hit while driving.

  11. #51
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    Quote Originally Posted by 06300CSRT8 View Post
    I am still not convinced the car will have a similar issue once you actually start to drive it. On many of my setups I tuned, in neutral if say I would put the pedal to 30% and hold it, the rpms would shoot up, fade off, dip, then climb again. Logs showed a lean wave of fuel coming in and out. I was basically teasing the very very far left bottom of the VE table, which you CAN NEVER hit while driving.
    I'll definitely get some logs on the road, hopefully tonight. And of course, now it decides to start raining. Hopefully I don't "find" another telephone pole.

    P1010848_SM.jpg

  12. #52
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    I made an attempt to do some drive testing this weekend. I wasn't even able to do that. This current condition makes it undriveable.
    It acts just like when a carburated setup has either super low fuel pressure or a trashed accelerator pump.

    My fuel pressure is fine and seems totally consistent with what I'd expect with the boost/vac referenced FPR. I also did a quick and dirty vacuum leak check with a can of ether.

    I'll link a video clip, along with the log, of the issue while in park. It's nice that you can see the throttle linkage movement.
    If you notice, when the throttle cracks open a decent amount, the RPMs fall and sometimes you get a lean pop.
    Start the video when the log hits the 00:59:402

    Video Clip: https://youtu.be/tRGIADxvsx4
    Log File: A-Bom_LSFO_007j_12.2 Warmup Video.hpl
    Tune File: MattL 2006 300c ABom_LSFO_007j.hpt

  13. #53
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    I cant open your latest tune here at work since I need to update my version.

    But all of this looks like fueling / VE tuning to me. Your surging at idle, even with the car in open loop, tells me your timing is still too "cliff" like right above idle (guessing your are around 14 commanded at idle but prob near 20 at 1200), might want to smooth that out. You also need to loosen up your throttle proportional gains in your electronic throttle tab if you haven't already, the proportional in p/n and in drive should cut in half on the throttle side.

    The going lean north of 1.0 pressure ratio is also all just fuel tuning, need to get aggressive and with your VE table in the transition to boost area of your tune. Its really hard to tell because you are in neutral and not driving, but you should be tipping into WOT fueling with how far you are leaning into the throttle.

    Is everything ok mechanically with your bypass? I have never seen a car make that much boost just free revving in neutral. Very good chance you are simply blowing out your spark plugs with that much boost so low in the rpm range. Blow out will read a false lean, as well.

  14. #54
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    Quote Originally Posted by 06300CSRT8 View Post
    I cant open your latest tune here at work since I need to update my version.

    But all of this looks like fueling / VE tuning to me. Your surging at idle, even with the car in open loop, tells me your timing is still too "cliff" like right above idle (guessing your are around 14 commanded at idle but prob near 20 at 1200), might want to smooth that out. You also need to loosen up your throttle proportional gains in your electronic throttle tab if you haven't already, the proportional in p/n and in drive should cut in half on the throttle side.

    The going lean north of 1.0 pressure ratio is also all just fuel tuning, need to get aggressive and with your VE table in the transition to boost area of your tune. Its really hard to tell because you are in neutral and not driving, but you should be tipping into WOT fueling with how far you are leaning into the throttle.

    Is everything ok mechanically with your bypass? I have never seen a car make that much boost just free revving in neutral. Very good chance you are simply blowing out your spark plugs with that much boost so low in the rpm range. Blow out will read a false lean, as well.
    I think I'm on board with your line of thinking. I started upping the VE to richen up the fueling overcome the lean out, but then the idle went all to hell. I'd dropped the timing to 14 around the idle area after seeing others have success using that to tame a larger cam since the higher timing would overreact and overshoot the target TPS.
    I got into a whirlwind of cause/effect and not exactly knowing which was which.

    I'll be switching out the injectors for the ID2000 units here soon. Then I know I'll have solid injector data to work with.

    As far as the mechanical bypass, there isn't one. The 6-71 setup never had one other than a burst plate in case of a backfire between the blower and the valve. So, that boost is just from moving that much air I suppose. I believe a 6-71 displaces about 426ci per rotation and I'm just a touch about a 1:1 ratio on the pulleys.

    I just realized a possible "DUH" moment, my base timing table only goes up to 105 kPa. I thought it would just carry the highest row of numbers past the top axis, but that may not be the case.
    Here's a snapshot of my base timing table for reference...

    ABom_LSFO_007J.jpg

  15. #55
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    You are def tripping into WOT timing, which means itll follow the WOT base timing table, which should be scaled out past 105kpa.

    Your VE needs a heavier ramp vertically, not horizontally. You are going from top of the grid to the bottom within a few columns. Focus your tweaks there.

  16. #56
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    Quote Originally Posted by Mattechperf View Post
    Yes, the primary TB is DBW like stock and a slide type link bar attaches the two with different ratio arms on each
    I am at a loss for what is going on with your car, but I will say the throttle body adapter and linkage is awesome looking!!!

    Mike

  17. #57
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    Quote Originally Posted by 06300CSRT8 View Post
    You are def tripping into WOT timing, which means itll follow the WOT base timing table, which should be scaled out past 105kpa.

    Your VE needs a heavier ramp vertically, not horizontally. You are going from top of the grid to the bottom within a few columns. Focus your tweaks there.
    WOT Spark goes up to 150 kPa, so we're good there. (Pic below)
    I'll bring my idle RPM up, bring the VE up, and see how she rolls.

    ABom_LSFO_007J_WOT Spark.jpg

  18. #58
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    Quote Originally Posted by 06300CSRT8 View Post
    You are def tripping into WOT timing, which means itll follow the WOT base timing table, which should be scaled out past 105kpa.

    Your VE needs a heavier ramp vertically, not horizontally. You are going from top of the grid to the bottom within a few columns. Focus your tweaks there.
    Well, to everyone who put their money on lack of fuel, you win the pot!
    I ramped up the VE table in lower left corner, raised the entire table by 10%, and then backed down 5%. The idle will need some work, but that damn cut out is almost eliminated.
    It started doing an odd thing where, after a good throttle pedal stab, the commanded TPS would give it another stab, almost like an echo, which would send the RPMs way up.

    I'll attach the latest tune and log, as well as a pic of the throttle anomaly mentioned . I'm going to install the ID2000 injectors and rebuild the TB airflow tables with the numbers I calculated for the dual TB setup.

    MattL 2006 300c ABom_LSFO_008a.hpt
    A-Bom_LSFO_007j_13 VE Lowered all 5%.hpl

    A-Bom_LSFO_008a_Throttle Echo.JPG

  19. #59
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    That echo is all in your airflow settings. Try your min airflow settings, try lowering them. It doesn't know you've got two throttle bodies worth of air and the system is designed to "catch" the rpms with a min airflow as the rpms fall. Its the same "coasting rpm" issue manual cars have when you stab in the clutch while coasting and the rpms will suddenly rise out of no where. Self cruise control some call it.

  20. #60
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    Quote Originally Posted by 06300CSRT8 View Post
    That echo is all in your airflow settings. Try your min airflow settings, try lowering them. It doesn't know you've got two throttle bodies worth of air and the system is designed to "catch" the rpms with a min airflow as the rpms fall. Its the same "coasting rpm" issue manual cars have when you stab in the clutch while coasting and the rpms will suddenly rise out of no where. Self cruise control some call it.
    Good call. I'll give it a try.
    Regarding "min airflow" settings. Do you mean Desired Airflow Minimum or did you mean the lower voltage area of the ETC Throttle Body Airflow table?
    Also, I assume I'd be looking at "Total Airflow" in my logs when looking at this, correct?
    My last log has the Total Airflow of 57.5 g/s at 2042 RPM, but goes right to 0.9 g/s at 2317 RPM.

    Here's what I have for the Desired Airflow Minimum:
    ABom_LSFO_008a_Desired Airflow Minimum.jpg