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Thread: Vortec 454 w/ cam, injectors-timing help?

  1. #1
    Potential Tuner
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    Aug 2015
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    Vortec 454 w/ cam, injectors-timing help?

    Hello all,

    I was hoping not to post until I was a more informed poster, but things didn't work out that way. I come now for hopefully a "yes/no" the tune is safe to go pick up my 5th wheel and pull it 1.5hr home, and maybe some guidance for changes. The trailer is light, 5500lb, but will load up the engine well due to the wind. I pulled a heavier trailer with a fullsize van on it (6.0, 2wd 4l80e ) and logged that run so I have a good log to show. My tune isn't as refined as it should but it hasn't been top priority as my mom just lost her fight with cancer.

    The engine is a 99 Vortec 454 in a K2500. It has a Comp Cams 01-415-8 (218/224 .500 lift 113LSA), comp cams valve springs, 29lb/hr ls1 injectors and an 0411 pcm. The MAF is set to fail on first code, Fail freq=0 for VE tuning yet.

    I was not sure what was a good timing table to use. The 8.1 seemed very high. I took the 5.7L tune and added 2 degrees across the board. This seems to compare quite closely to a stock 7.4 timing table (which is MAP vs RPM not g/cyl vs RPM). I had forgotten to make high and low spark tables equal at the time of the log.

    On my logged run the engine does a few funny things. At one point (frame 8611) KR ramped up to 6 degree, tps was constant 33%. That was the bigger KR spike, a few other cells hit KR=1. This is around 1500-2000rpm and 0.3-0.6 g/cyl

    I have the Engine_general_Type as 8.1L. 7.4L is not an option in the pulldown menu. Should this have remained at 5.7?

    Other spots in the log show the timing dropping by 30 or 35 degrees to 4.5 and 0 degrees respectively. Frames 6500 and 6770. Is this DFCO effect or something else?

    I attached the tune, the log and the config although I just used default metric.

    Thanks in advance, I'll check back often in case I missed providing any other data. I would like to go for the trailer within the next few days, rent on the site expires this month.
    Attached Files Attached Files

  2. #2
    Tuner in Training
    Join Date
    Nov 2014
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    12
    so how did the dragging back the 5th wheel go?

    would like to see more on vortec L29 7.4's with 0411 swaps as i will be doing the same to my personal truck

  3. #3
    Advanced Tuner AutoWiz's Avatar
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    Aug 2015
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    South Florida
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    That main spark table sure does look smooth. Now if you could just do that for the main ve table, you will be in good shape

  4. #4
    Advanced Tuner
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    Nov 2015
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    To answer your questions:

    The timing dropping to near 0 is almost certainly DFCO, the conditions looked right for it with your settings.
    The minor 'blips' in KR I wouldn't even care about, 1 degree is neither here nor there, so long as its just momentary, as yours is, and ramps right back down.
    But the one 6 deg. event is a bit odd, you can see your fueling went dead lean for about a second, even though your TPS etc. was unchanged, it was (apparently) in a "steady state", constant speed and presumably load... not sure why that was!

    One more thing, at the end you are idling and the idle is cycling (up...down...up...down..) thats a sign that the idle setup needs adjusting a bit.
    99 TA, Texas Speed LS376, PRC heads, 233/239 cam, Fast 92mm, 95mm TB, card style MAF, Tick TR6060, Strange 4.11 12 bolt axle & clutchpack diff, Strano springs/dampers, Vette 18" wheels, Vette disks, CTS-V calipers, 16lb flywheel, long tube headers, no cats.