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Thread: G8 L76 Tuning

  1. #1
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    G8 L76 Tuning

    Ok so I've got my G8 L76, Custom CAI, 1 7/8" Primary long tubes, cat-delete, 3" magnaflow cat-back, LS7 MAF, Cam 218/232 @ .050 .596/.608 lift. Car is running great except for it will occasionally stall when coming to a stop and I just can't seem to figure out how to tune it out. I'm relatively new to tuning with HPtuners and could use some input from the tune gurus here and I'm attaching my latest. Help?
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    Last edited by G8orade; 03-25-2021 at 12:29 PM.

  2. #2
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    So I've been tweaking the tune the last few days, even managed to get an engine stall recorded. Stall only occurs when returning to idle, any thoughts would be appreciated.
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  3. #3
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    The primary issues are that the target idle speed is too low and the Base Running Airflow table is just too low.
    I would typically start around 700-750 rpm with a cam of that size, and base airflow needs to be at least 20-25% higher as well.

    A couple more tips for you...
    Your target AF ratio at WOT is pretty high. Once you install a wideband, you can get it dialed in pretty well. Around 12.8:1 actual AF ratio will be a good number for your application.
    You might disable the brake torque management too. That'll make it fun to drive.

    Your WOT shift rpm is a bit too aggressive with that cam. I would drop it down to around 6500rpm.

  4. #4
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    Quote Originally Posted by kevin87turbot View Post
    The primary issues are that the target idle speed is too low and the Base Running Airflow table is just too low.
    I would typically start around 700-750 rpm with a cam of that size, and base airflow needs to be at least 20-25% higher as well.

    A couple more tips for you...
    Your target AF ratio at WOT is pretty high. Once you install a wideband, you can get it dialed in pretty well. Around 12.8:1 actual AF ratio will be a good number for your application.
    You might disable the brake torque management too. That'll make it fun to drive.

    Your WOT shift rpm is a bit too aggressive with that cam. I would drop it down to around 6500rpm.
    I don't know why it took me 3 days to notice this but thank you for the tips and I'm currently applying them to my tune. Hopefully this solves my issues.

  5. #5
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    Hey there ever figure out the stalling issue I'm having the same problem

  6. #6
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    idle airflow. idle rpm. base idle spark, startup rpm. and airflow. along with throttle follower torque must be increased in order to prevent stalling. Try a little at a time until you have suitable idle stability when coming to stop.

  7. #7
    Advanced Tuner dhoagland's Avatar
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    Quote Originally Posted by G8GTAldog View Post
    Hey there ever figure out the stalling issue I'm having the same problem
    If no body responds, Create a new post with your tune file and a log
    2011 Camaro 2SS Convertible L99 Bone Stock for now
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  8. #8
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    brought up my idle to 725 and adjusted up my idle air flow by approx 30%. I'll attach my latest tune if you want to look at it. No stalls with this tune.
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  9. #9
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    Glad you were able to make progress, looks decent. If any stalls appear after the tune settles in, raise the min airflow table in small amounts, in the rpm area that your idle is set for

  10. #10
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    Yeah it's running a lot better now. I haven't had a stall in 2 weeks, what I'm working on now is trying to figure out why I can't seem to get my car to let me do a burnout. The brake torque management is turned off and I set the table to what I would think should have allowed me to overpower my brakes but the car limits me to around 30% throttle electronically. Any thoughts on that would be great. It's a daily driver but who doesn't love burning off a pair of shoes when you buy a new set?

  11. #11
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    I have left the Brake Torque Management enabled but the Brake Torque Limit table is completely maxed out. No burnout issues here!

  12. #12
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    Max TCC limit and stall torque settings in the transmission tables and try to do your burnout, also disable fast torque exit in engine torque management area

  13. #13
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    Between turning brake torque back on and maxing the tables and adjusting my TCC settings we have a solved problem. Last concern in a slight burble where I'm getting thrown into spark KR coming off idle with heavy throttle. It's way better than it was but could that very well just be a need to retard my timing some more? Thoughts?

  14. #14
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    Bumping because I still have that burble coming off idle, current tune attached.
    G8R Tude MK LXXVI.hpt

  15. #15
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    Did you tune the vve tables? they seem lean. Also raise the high octane spark timing tables in the 600 to 1200 areas, add about 4*. Your over/under spark tables can be cut in half for all modes too. Max throttle opening rate in all gears
    Last edited by FASSTRUK; 05-05-2021 at 08:42 PM.

  16. #16
    Quote Originally Posted by G8orade View Post
    Yeah it's running a lot better now. I haven't had a stall in 2 weeks, what I'm working on now is trying to figure out why I can't seem to get my car to let me do a burnout. The brake torque management is turned off and I set the table to what I would think should have allowed me to overpower my brakes but the car limits me to around 30% throttle electronically. Any thoughts on that would be great. It's a daily driver but who doesn't love burning off a pair of shoes when you buy a new set?
    Press tc switch (turn traction control off). Put trans in manual mode but do not tap up or down- just move shifter right and it will auto shift.( if you tap up or down, it will go full manual)- ---- BURN EM UP
    its actually the brake signal that limits your throttle rev to 30%.
    Last edited by goodwrenchdave; 05-09-2021 at 07:21 PM.

  17. #17
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    Yeah I got that all figured out and fixed a couple weeks ago, still having that burble off the line but at least I know what's causing it now. When I step on the gas hard from idle i have an AFR spike up towards almost 23:1 and it's causing my spark to knock and go into retard until around 2k and then it's smooth as butter and power all day. My interpretation of this is that my fuel is lagging behind my airflow for a second. Any thoughts on correcting that concern? Tune and log attached. Just a quick couple of throttle hits but it illustrates the concern adequately.
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  18. #18
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    Problem solved guys. I had apparently completely overlooked making adjustments to my Idle Throttle Follower coefficients when adjusting my idle airflow last month. Throttle response in crisp and sharper than ever. Thanks for the help guys.

  19. #19
    Senior Tuner TheMechanic's Avatar
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    Quote Originally Posted by G8orade View Post
    Problem solved guys. I had apparently completely overlooked making adjustments to my Idle Throttle Follower coefficients when adjusting my idle airflow last month. Throttle response in crisp and sharper than ever. Thanks for the help guys.
    Do you mind showing your after fix .hpt?

  20. #20
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    Yeah, absolutely. I still may tweak it one or two more times but this is the current tune that has eliminated the concern.
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