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Thread: Lacks power in upper RPMs

  1. #1
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    Default Lacks power in upper RPMs

    This is my current tune after completing the AutoVE and posting to my original tune. The engine fires up a lot easier and the power comes on a lot faster but the upper RPMs of power falls off after 4000. I know the VE table has a lot of valley and peaks, but i did drive the truck for almost 20 mins trying to hit as many cells as possible. Seems pretty hard to get all of them to a 50+ count.

    So i have two questions here then:
    1. How do i get all the cells 50+ so i can get a better and more accurate tune
    2. What needs to be done to get rid of the upper rpm drop in power.

    I have posted my tune here and the log file
    Attached Files Attached Files

  2. #2
    Joe (Moderator) joecar's Avatar
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    If you're trying to do AutoVE, your tune file still has closed loop enabled and MAF enabled...

    You logged wideband AFR shows you are quite rich, your initiial bump up of the VE table should have been maybe 8% rather than 15%.

    Try this:
    - disable CL and MAF (go thru the Auto VE tutorial again),
    - smooth those peaks out of the,
    - flash that in,
    - set your cell count to 10 or 20,
    - do another iteration.

  3. #3
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    I did only increase the VE table for the AutoVE procedure by only 8%. The tun file attached is the adjusted file with all of the AutoVE disabled. How else can i accurately hit all the cells and smooth out the peaks and valleys of the new tune file? Do i need to just drive and log a lot more in one trip? Thanks again guys!

  4. #4
    Joe (Moderator) joecar's Avatar
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    Oh, I see...

    Yes, just drive more, manipulate the throttle in a smooth manner (this will cause the BEN transient filter to keep more data)... but watch out (you'll be going pretty fast), set the cell count to say 20...

    The cells you don't hit are ok (you probably won't ever hit those on the street), just smooth/blend them with the rest of the table...

    That flat depressed part of the VE table, is that where your BEN map is hitting...?
    If so, then the initial 8% was maybe too high... what mods do you have...?

    make the surrounding table blend with that flat part, mash the peaks down to that same level, and try again.
    Last edited by joecar; June 9th, 2009 at 06:37 AM. Reason: Typo

  5. #5
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    I see what you are saying. I have noticed that i was able to hit cells by downshifting real early aznd letting the braking force of the engine that i would never be able to touch with just using the gas pedal.

    It seemed that the resultant average of the BEN cells on the map came to a value of 0.8. Almost every cell that was analyzed when driving came to that value. Is there a way to multiply all cells of the original VE table to acquire data relatively close to what it resulted? How do i smooth out the cells?

    Yes, the lower smoother parts of the table are the result of the modification of the VE table.

  6. #6
    Lifetime Member mr.prick's Avatar
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    Log battery voltage at higher RPM and see if it dips.
    512k RoadRunner Firmware 12.14R
    FlashScan V2 Bootblock V2.07.04 Firmware V2.07.22 EFILive V7.5.7 (Build 191) V8.2.1 (Build 181)
    LC-1 WBO2

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  7. #7
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    Battery voltage is good at upper RPMs. What is the best way to get a good result from the AutoVE?

  8. #8
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    Anyone have any tips they want to share on how to properly solve this dilemma? Or how you have made your AutoVE work well for you?? Thanks

  9. #9
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    Hills are good, especially long steep straight ones and so is a lot of weight as it makes the engine work harder. Filling the car with friends, towing a trailer, anything to make it accelerate slower so you can hit more cells while going slower.

    Ira

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