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Thread: How to raise the rev limiter on a lmm pull truck

  1. #1
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    Default How to raise the rev limiter on a lmm pull truck

    I have tuned my 1st pull truck and went to the pulls to watch my truck run--
    It is a 2007 LMM and runs in the "modified street " class at 8000 lbs
    Afterwards I spoke to many of the other drivers and it seems ALL of them rev the engine up to 4800 RPM--Ours would only top out at 3800-4000 RPM
    These are all race only dedicated pull trucks and no need to criticize the engine danger this does
    How or what do I need to do in the tune to get the engine to rev up to 4800 initially from the start of the pull ?
    I made all the adjustments in the TCM and ECM I thought would do it but they did not work
    The drivers all run in MANUAL mode and do NOT shift--They run in 3rd gear in 4WD drive low---
    I am using EFILIVE-- Thanks

  2. #2
    Lifetime Member GMC-2002-Dmax's Avatar
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    Maybe the truck is not making enough power to turn any higher rpms ??
    www.mscservices.net


    Tuner of many, many Duramax and Cummins Diesels.


  3. #3
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    I have about a 175-200 HP tune in the truck
    Also I extended all the timing-boost and fuel tables up to the 4800 mark
    In the TCM I also raised all the shift at WOT RPM tables to 5000 RPM
    Still the trk only hits about 4000
    Are LMM's limited somwhere's else or built into the ECM to only rev to 4000 ?
    OR have ever seen an LMM be able to rev higher ?
    Thanks

  4. #4
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    RESOLVED---- We were testing off road in 4WD and low in 3rd gear manual mode and found that the engine did not have enough "load" to rev up past 4000 RPM's But when we took it to the next pull race and under full engine load it did rev up to 4800 RPM's and my driver WON the race !!!
    congrats to Scott Avis from Elk Grove Calif----- 8000 Lb Super Street Class---

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