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Thread: Check this tune please

  1. #1
    Tuner in Training
    Join Date
    Apr 2019
    Posts
    13

    Check this tune please

    I have a 2000 firebird with an ls mix. Lq4 block, eagle forged crank, Gen4 rods, Custom 10.5:1 pistons, Lunati 243/259 651/651 112lsa cam, Edelbrock super victor intake, FAST 4150 throttle body, SVO 42# green top injectors at 50 psi fuel pressure deadheaded with no return line, Ported and polished 823 heads with BTR 660 dual springs, 1 7/8 long tube headers dumped at the rear axle. Innovate Motorsports wide band.
    The issue I have is the previous owner just track raced the car with a 150 shot. He pulled the kit prior to me getting the car. The tune runs strong above 2500 rpms, but is a slug down low and has bad idle issues. Local tuners have not tuned this intake combo before and have no idea where to start. I have bought a HP tuner and am going to try to weed this out myself. I will attach the tune. The VE main table just doesn't look like any others I have seen. Any help as to where to look idle wise would be appreciated.
    Attached Files Attached Files

  2. #2
    Advanced Tuner
    Join Date
    Feb 2015
    Location
    Perth, Australia
    Posts
    974
    I can fix it for you and point you in the right direction but I'd have to license the file which I'd rather not do.

    few things.

    you'll need to log TPS% so you can confirm o% at idle and 100% at WOT.
    that cam is large and will likely idle with much more stability at a richer AFR like 13-13.5
    the timing at idle is huge meaning it has no resolution to work with for addition and subtraction to control idle. I would personally want to be around 15ish at temperature
    your idle overspeed spark correction table is adding from 50-100RPM error when it should be subtracting. this will cause erratic idle as the corrections are making it worse.
    it needs more base airflow
    good chance it wants more air mechanically by adjusting the throttle stop and re calibrating 0% position
    the VE table looks like he's tried to correct for incorrect (lean up top) nitrous fueling with the PCM calibration.
    the IRF vs manifold vac table data looks too big by about 20% hence large VE table numbers for N/A
    turn EGR switch off
    its getting quite warm at idle 106C coolant.

    I wouldn't expect the most responsive engine below 2500rpm with a cam that big.

    what driveline? what cubes?

  3. #3
    Tuner in Training
    Join Date
    Apr 2019
    Posts
    13
    He said stock 6.0 bore. TH 400 reverse manual valve body with trans brake. 9 inch with 4.10. Not sure on converter but feels like 3500 stall. It has a lingenfelter 2 step that is set to 3400. I have only driven it a little. The mid range and up is crazy responsive. Motor is very strong there. It just wants to fall on its face at idle. I will look over the tune and see if I can understand what your seeing and make the adjustments along with a new log with tips percentage. Thanks for the help as this is all new to me. I can carb and distributor tune, just need to understand how the adjustments are made this way.

  4. #4
    Tuner in Training
    Join Date
    Apr 2019
    Posts
    13
    Egr switch is on as that's where I have the wide band reporting. I will see if I can adjust the idle timing and move forward from there.

  5. #5
    Tuner in Training
    Join Date
    Apr 2019
    Posts
    13
    The IRF table you mention, Is this the injector flow rate table?