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Thread: Commanded afr not matching

  1. #1
    Tuner in Training
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    Oct 2009
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    Commanded afr not matching

    Hey guys, first off I am very new to this.

    I tried doing a start up tune for my 230/234 .612/.590 spinmonster cam in my 2008 ls3 M6 corvette

    What I have found is a few things,

    1.) is my commanded AFR should be ~12.53, as my multpliers are 1.17, and my stoich is 14.67. However, when i start it and let it warm up to operating temps, the commanded AFR is ~11.90, (actual is around 12.90 as I havent messed with the maf much yet)

    why is this so, I want to command 12.5, and tune to it, and this just seems to flaw my whole understanding of the software.

    2.) my old base header tune, idled great with this cam in, it would purrr at 650 rpm, and when revved it would fall right back to 650. Now that I have increased the airflows, it seems to hang up at 1050rpm, and then dip below 650? Seems like I should have stuck with the non tuned idle settings. does anything look messed here? (probably most of it)

    I have not been able to take the car out of the garage as its still snowing here, the intake temps are in the 45* range, so I figured I gave my multipliers plenty of room.

    Any help would be great. This tuning thing isn't as easy as it sound, does anybody one here do remote tunes for $$?

    2008 LS3 M6 corvette. Headers, no Cats, Airraid intake, 160 degree thermostat, 230/234* cam, 125hp N20 shot

    2006 LBZ duramax 5" exhaust, boost fooler, Bully dog pmt, 6" lift, 37" rubber on 20" rims, and maybe some HP tuning...

    2010 Chevy 1500 reg cab SB 4x4 , 5.3, Magnaflow cat back, 24's, 2" drop, K&N element, custom leather

    1988 S10 Blazer- Vortec 383, built 700R4, doubler, front 3 link with 14" CO's, rear 4 link, 42" Iroks. 35 spline 4340 D60's front and rear.

  2. #2
    Senior Tuner DSteck's Avatar
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    I might have a chance to help you this weekend. That shouldn't be a hard cam to dial in at all. As far as commanded AFR, the IVT open loop table is skewing that.

    DSX Tuning - Authorized HP Tuners Dealer
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    Just say no to bull s***.
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  3. #3
    Tuner in Training
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    Still snow here right now, It will probably be a couple weeks before the roads clear up. I will shoot you a PM. I'm in no crazy rush.

    I changed my IVT table to 1 in all cells, I will check that out later. Thanks Dsteck I appreciate it.

    2008 LS3 M6 corvette. Headers, no Cats, Airraid intake, 160 degree thermostat, 230/234* cam, 125hp N20 shot

    2006 LBZ duramax 5" exhaust, boost fooler, Bully dog pmt, 6" lift, 37" rubber on 20" rims, and maybe some HP tuning...

    2010 Chevy 1500 reg cab SB 4x4 , 5.3, Magnaflow cat back, 24's, 2" drop, K&N element, custom leather

    1988 S10 Blazer- Vortec 383, built 700R4, doubler, front 3 link with 14" CO's, rear 4 link, 42" Iroks. 35 spline 4340 D60's front and rear.

  4. #4
    Senior Tuner DSteck's Avatar
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    Mar 2008
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    St. Louis, MO
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    4,860
    I wouldn't change the whole table to 1. You want some enrichment at cooler temps (below 170s or so).

    DSX Tuning - Authorized HP Tuners Dealer
    http://www.dsxtuning.com
    http://www.facebook.com/dsx.tuning
    Just say no to bull s***.
    IF YOU WANT HELP, POST A FILE!