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Thread: LML Will not build over ~22PSI of boost

  1. #21
    Lifetime Member Mitco39's Avatar
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    Quote Originally Posted by GMC-2002-Dmax View Post
    I have seen avg vane% of 74% to as low as 45% and meets target boost, but at WOT it still drops to 0% vane but does make boost.

    I am not too concerned with the 0%, I am loading a new tune now for 35psi and we will see what that makes vs. vane %
    The 0% is exactly what you want once it has made its goal boost. No reason to increase drive pressure for nothing after the fact. I look forward to hearing what you find.

  2. #22
    Lifetime Member GMC-2002-Dmax's Avatar
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    I just tried a 2011 a 2012 and a 2013-2014 OS and they all goto 0% at WOT.

    So I don't see any difference between how they run at wot.

    I still think we have some tables missing for vane position control beyond what we have.

    Tony
    www.ridgerunnerdieselperformance.com

    tony@ridgerunnerdieselperformance.com

    Tuner of many, many Duramax and Cummins Diesels.


  3. #23
    Lifetime Member Mitco39's Avatar
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    Tony,

    Have you tried maxing out those efficiency tables under the misc folder in the turbo section? Doing this I was able to get up to 30% at WOT.

  4. #24
    Lifetime Member GMC-2002-Dmax's Avatar
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    Without a drive psi gauge we have no idea if that is causing excessive drive psi.

    If I have time I will play around some more with it.
    www.ridgerunnerdieselperformance.com

    tony@ridgerunnerdieselperformance.com

    Tuner of many, many Duramax and Cummins Diesels.


  5. #25
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    I don't see any explicit table that is pushing the vanes to 94%.

    I will keep picking through the binary though. Seems like the vane position you guys are logging is a result of a calculation that is not directly calculating position- but maybe shaft speed or EGT or something...

    It makes sense that the vanes would open at WOT- to avoid high shaft speed and high egt. I would think making these tables one constant value- pick one- any one- and logging to see what's up would work. Put a low value in and see if it won't build boost anywhere- then keep upping the value and see if you can surpass your previous road block.

    Just an idea.

  6. #26
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    Quote Originally Posted by Mitco39 View Post
    The 0% is exactly what you want once it has made its goal boost. No reason to increase drive pressure for nothing after the fact. I look forward to hearing what you find.
    are you sure this is correct?

    I feel like once you are at target boost you want to vary compressor flow with RPM- so even at target boost vanes(shaft speed) should still be moving to adjust for RPM changes. No?

  7. #27
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    another thought- can calculated shaft speed and/or EGT be logged with desired boost and actual boost?

    That would tell us quite a bit.

  8. #28
    Lifetime Member Chavez91's Avatar
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    Quote Originally Posted by RADustin View Post
    are you sure this is correct?

    I feel like once you are at target boost you want to vary compressor flow with RPM- so even at target boost vanes(shaft speed) should still be moving to adjust for RPM changes. No?
    I believe this is correct. There are alot of variables such as the compressor map and drive pressures that would need to be considered to find the ideal Vane position. 0% isnt just "what you want".... When pushing the limits of the charger, Target boost may need to actually be lowered in psi at higher rpms (As cfm demand increases) so you can keep the compressor in its map.
    Josh
    '04 LLY
    LML Hybrid with Built Trans
    500K Miles

    '05 LLY
    *Built Trans & Tune Only*

  9. #29
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    why dont you guys change B1204 and relog.

    that will show if the truck is limiting explicitly to 94% or 0% or whatever- basically show if the truck is limiting vane percent. We know 0 volts is 0%, but if you lie and say 1 volt is 0% then the truck will command ~20% in actuality when it thinks its commanding 0%. This should lock in more boost unless something else is limiting. that will at least cross off vane position being explicitly limited- I think so anyways- thoughts?


    does anyone still think the truck is simply limiting mass air flow?


    Also- dumb question but has anyone made sure the boost sensor can read higher than 34psi?

  10. #30
    Lifetime Member GMC-2002-Dmax's Avatar
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    I believe there are temp ad-on tables or limiter tables, in the testing I did, at least for idle the vanes will go-to the Open Loop Targets under 155-160 degrees, at some point around 160 degrees on the 2012 OS they add vane% to target in the Open Loop tables, also in reverse when load increases the vanes will then reference target in the open loop tables.

    I also used my TECH2 to do a full VVT Vane relearn and drove the truck, still saw 0% at wot.

    We are missing tables, I know in BETA one of the other testers was trying to tune a twinned LML with what we have and commented that he also though we needed some more control over the vanes, but with everything else going on it was not revisited.

    I am going to see if I can do some more testing by increasing the % closed in the Open Loop Tables for VVT control, but when I check with the tech2 the learned position min/max matches closely to what I see other than in idle/park or idle/neutral.

    Maybe a VVT Target position in idle ???
    www.ridgerunnerdieselperformance.com

    tony@ridgerunnerdieselperformance.com

    Tuner of many, many Duramax and Cummins Diesels.


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