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Thread: LMM Newb questions

  1. #1
    Tuner in Training
    Join Date
    Jan 2008
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    LMM Newb questions

    All,
    I've spent some time going through Roger and Mechanicman's posts, and now I have a few quick questions. When talking about a 20/20 tune is this 20% fuel added and 20% timing or boost added? As for timing goes, correct me if I'm wrong but more timing (to a certain point) = more mpg/power correct? Why then do the example calculator tables show a lower number in the cruise area than the stock table? I have an 08 LMM that I am looking to just add timing and possibly 5% fuel or less. I don't need another rocketship, I just want driveability with some more bang for my buck (MPG's). I am familiar with LS1 HPT stuff and am familiar with the older cummins stuff (VP44), but this whole duramax thing has me a bit confused . Any insight into this would be helpful. Also, could someone clarify exactly what the timing calc does when you enter 50%? Would this be like adding 50% to the table or what? Thanks for your patience in advance!

    Mike
    1998 Camaro M6 - 99PCM, Darton sleeved ls1 427, PRC 2.5 LS6 heads, LS7R cam, UMI goodies, Baer Brakes, Trans by Tick, Waiting for rear end to go bye bye

  2. #2
    Advanced Tuner ajamesbond007's Avatar
    Join Date
    Dec 2010
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    Near Wilmington, OH
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    50/50 timing is splitting the injection pulse 50% Before Top Dead Center, and the last 50% is After Top Dead Center. a 55/45 will give you slightly better economy, and a 40/60 split will give you slightly better power
    Andrew
    andrewjamesbond1@gmail.com

    2006 Duramax ECSB - Banks Monster Dual Exhaust, Tie Rod Sleeves, Kennedy Twin Deluxe Lift Pumps, Edge Insight CTS with Pryo, EGR Blocker Plate, PVC Reroute, Suncoast Stage 5 trans with 1056 triple disk converter, Cognito Steering Braces, PPE Race Valve, LML driver side exhaust manifold, AFE Boost Tube, Stock Drop-in BatMoWheel, ProFab Performance 3" Downpipe, Other mods along the way, TUNED by ME... Way too much fun

  3. #3
    Tuner in Training
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    Apr 2007
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    LA
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    You can also do a "multi-timing" table, where as you use more timing 55% in the cruise areas i.e. less than 45% throttle up to 1900 rpm and then get more aggressive as you throttle more.

    I believe that either Roger or Mechanicman had a snapshot picture of what that the timing table would look like.

    I built one for an 09 truck and it works nice so far, its only a few days old and the driver hasnt taken his foot out of it long enough to get some MPG numbers, but scanning and testing while cruising showed real nice trends.

  4. #4
    Tuner in Training
    Join Date
    Jan 2008
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    Ok, Got the table and followed mechanicman's tutorial.... but my question is, when copying the table's on an lmm, do I copy the base pressure low alt lo, and the default low alt lo for the timing as well? Not sure which to use to input into the table. The tutorial was done with an LLY I believe which has some different tables to copy.

    Thanks!
    1998 Camaro M6 - 99PCM, Darton sleeved ls1 427, PRC 2.5 LS6 heads, LS7R cam, UMI goodies, Baer Brakes, Trans by Tick, Waiting for rear end to go bye bye