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Thread: Bigger cam and Timing tuning Methodology (4.8 212/218 112 lsa cam)

  1. #1

    Bigger cam and Timing tuning Methodology (4.8 212/218 112 lsa cam)

    Truck has a 4.8 with a 212/218 112 lsa .550/.550, intake, catless LTs. I'm curious to get input on peoples theories on LS timing with a cam. I have read through a lot of post and forums from various sites and some say to throw a bunch of timing, some say less is more. I see a lot of repository tunes where the curve ramps up and levels off. I was under the theory that as the cylinder air increase, timing decreases, thus a timing curve. I currently have less timing then stock because street tuning and riving hills it feels best. feels torquier. Just curious on theories or methodologies for tuning timing curve.

    AJ 6-19-17 2.hpt
    gfkgk.hpl

  2. #2
    Advanced Tuner BigDaddyCool's Avatar
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    Rule of thumb: most amount of timing for least amount of fuel.

    Quote Originally Posted by AJK13 View Post
    Truck has a 4.8 with a 212/218 112 lsa .550/.550, intake, catless LTs. I'm curious to get input on peoples theories on LS timing with a cam. I have read through a lot of post and forums from various sites and some say to throw a bunch of timing, some say less is more. I see a lot of repository tunes where the curve ramps up and levels off. I was under the theory that as the cylinder air increase, timing decreases, thus a timing curve. I currently have less timing then stock because street tuning and riving hills it feels best. feels torquier. Just curious on theories or methodologies for tuning timing curve.

    AJ 6-19-17 2.hpt
    gfkgk.hpl
    Last edited by BigDaddyCool; 06-23-2017 at 07:21 AM.
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  3. #3
    Using a dyno is the best way to determine timing/fueling.
    You can use a time/distance drive to verify your changes.
    How a vehicle "feels" is not accurate and can be misleading.
    You have to give an engine what it wants,not what is supposed to work.
    "Time it for torque, Jet it for horsepower."
    That is an old quote,that is still true.
    Keep watching for knock.That will hurt any engine,if excessive.
    Retarded timing can be harmful by making too much heat in the exhaust.
    That can lead to engine damage.
    These are ideas are based on my experience and should only be used as a guide.
    Last edited by Earwax; 06-23-2017 at 07:27 AM.

  4. #4
    or you cna check the trorque and see ho the timings affect it. It can be that lowering ther timing gives you more torque. if the engine che keep 20 degrees of spark advice without detonation doesn't mean it is what the engine wants.

  5. #5
    I guess with going turbo being so popular I see a lot more talk of boosted timing. And it seems with more air you put in the cylinder, the less timing you want. In my mind it seems linear, but I imagine thats nit always the case. I thought Stock timing curves seem to be so high because stock cams are small and GM likes to wait till the very last minute to dump fuel. I was more of a general thought, i.e. going from stock to bigger cam->might want to pull some timing before peak torque and adjust the curve. I like to tinker and understand how things work, and that's also why I like this forum. Full of info and different ideas.