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Thread: Slowly learning - critique my dontbsme tune

  1. #1
    Tuner in Training
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    Slowly learning - critique my dontbsme tune

    2002 RCSB Silverado. Pretty much copied the dontbsme combo
    Stock unopened 4.8, Sloppy Stage 2 cam, PAC1218s
    80E/HD2 with a Jake's 3200 street series converter, 4.10 8.8
    Billet 7875, VSR 44mm WG, no BOV, Deka 80s
    0411 PCM with 3bar MAP, no MAF

    Still working through VE tuning at cruise and part throttle, but my WOT seems okay in the mid 10s.

    I am still fighting a stumble on startup (more BRAF?) and some lean spikes during steady state cruise. My other "project" is working on adding some timing to all the non-boost cells as it's kind of a dog until the boost comes on. I think some added timing below 3000 would help the turbo light off sooner too. I've attached a "draft" tune with the stock timing copied over into the cells .5 g/cyl or lower, haven't tried it yet. Other than that it actually drives very nicely.

    Feel free to critique. I am a total newbie at this and am open to constructive criticism.
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    The open loop eq ratio should not be 1.00 for every cell. It's not ideal for the computer to command stoich when the engine temp is well below 100 degrees. There is a reason that the factory have the open loop eq ratio richer as the engine warms up. Partly for emission and most engines run better when it's a little richer on cold starts. You just want it to lean itself out to stoich past 130 degrees.

    Try to smooth out the VE to reduce the lean or rich spikes. The VE has pretty choppy when looking at the 3D graph.

    Try the new tune with more timing and the open loop EQ set back to a more stock like table and see how it is. Also remove the 1 bar MAP channel from the logs, you don't need it.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    Tuner in Training
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    Quote Originally Posted by 5FDP View Post
    The open loop eq ratio should not be 1.00 for every cell. It's not ideal for the computer to command stoich when the engine temp is well below 100 degrees. There is a reason that the factory have the open loop eq ratio richer as the engine warms up. Partly for emission and most engines run better when it's a little richer on cold starts. You just want it to lean itself out to stoich past 130 degrees.

    Try to smooth out the VE to reduce the lean or rich spikes. The VE has pretty choppy when looking at the 3D graph.

    Try the new tune with more timing and the open loop EQ set back to a more stock like table and see how it is. Also remove the 1 bar MAP channel from the logs, you don't need it.
    First off, thanks for your input, it's appreciated!

    VE definitely needs work. Still chipping away at that.

    It should be mentioned that the truck is fully open loop with no O2 sensors. Strictly using the wideband to tune VE. I will look at the OL EQ to try to richen it up for cold starts. Definitely has an issue always starting cold after a day or two.

    I've since removed the 1bar MAP in the scanner it was freaking me out watching boost peak at 105kpa while the gauge went to 8psi, lol

  4. #4
    Tuner in Training
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    Now that I have most of the mechanical bugs worked out I took it out tonight for some hits in Mexico. It seems to take forever to spool up and doesn't actually make peak boost until 4800. I'm wondering if that has something to do with it blowing through the stock muffler.....

    Stepslide Turbo Rev 9 wot TUNING.hpt

    big hits.hpl

  5. #5
    I responded to you on LS1tech. Shoot me a pm if you need some more help. there are quite a bit of things that need changed for it to run like it should.