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Thread: LFX Cam tuning

  1. #1
    Advanced Tuner
    Join Date
    Sep 2013
    Posts
    427

    LFX Cam tuning

    Hi there, was wondering has anyone had any great success in tuning the V6 With cams etc..Have any pointers or any guides to have a read through etc..

  2. #2
    i have the mace file they sent was supposed to be best for NA

  3. #3
    Tuner in Training
    Join Date
    Jul 2017
    Posts
    22
    I gleaned a clearer understanding of the cam timing by first knowing what the GM specs for the camshaft are. For example, the intake cam for the LY7 and apparently for the LLT which I'm working with, starts to open the intake valve at 14 deg ATDC and close the exh valve at 9 deg ATDC according to the GM shop manual. That is apparently from the parked position. In my graph logs in the scanner, the cam angles are absolute values, there are no negative values listed. In the tune however, the intake values start at 7 deg and progress from there toward 0 deg and beyond that are negative in the table. The exh values already being ATDC, all remain positive in the tune tables.

    I then noted in my efficiency graphs, that peak efficiency and power is always consistent with an intake cam angle of 15 deg and an exh angle of 5 deg. I interpreted that to mean that the intake camshaft is parked 14 deg from the straight up camshaft position and the negative values are to indicate the crankshaft degrees it is advanced beyond TDC. The +/- deg I'm seeing relative to stock may be because of a difference in the specs between the LY7 and LLT camshafts, and possibly a little compensation for 25k miles of timing chain wear since replacement.

    I understand the LFX intake camshaft has a little more duration than the LLT camshafts, but obtaining the specs would be helpful to you as GM did not update all of the specs between the LY7 and LLT motors as can be seen in my 08 shop manual, which appears to be a copy and paste as it lists the same compression ratio for both motors which is incorrect and cam specs.

    The LGX boasts an intermediate point locking camshaft actuator, perhaps that's the 14 deg advanced equivalent for the predecessors which all use the same actuators, parked 14 deg ATDC. The LFX uses a different PCM and as you may be aware of, a different table layout from the LLT.

    Once you sort out the table meaning, you can manipulate the overlap points in small increments to change performance and monitor it by setting up appropriate graphs for performance comparisons in the scanner.

    Hope this helps:

    https://www.performancetrucks.net/fo...-551391/page2/

    https://forum.hptuners.com/showthrea...VT-Tuning-info
    Attached Files Attached Files

  4. #4
    Potential Tuner
    Join Date
    Oct 2021
    Posts
    3
    do you still have the file?

  5. #5
    Potential Tuner
    Join Date
    Jul 2022
    Location
    Australia
    Posts
    1
    Quote Originally Posted by tlavoie87 View Post
    i have the mace file they sent was supposed to be best for NA
    Are you willing to send me the Mace file you have for me to have a look at please.
    Thanks in Advance

  6. #6
    Potential Tuner
    Join Date
    Oct 2022
    Posts
    3
    You speak about LFX, i have a gmc terrain v6 lfx and i want to know if someone have tunes the transmission with a switch to 6t70 to 6t80 ???