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Thread: Silverado 6.2 and WBO2 worth doing?

  1. #1
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    Silverado 6.2 and WBO2 worth doing?

    2011 Silverado 6.2, stock exhaust and CAI, been playing with the tune and would like to hook up my NGK AFX, is it worth doing?

    Reason I ask is I'm still running factory exhaust. As we all know, NGK states to place the sensor a minimum of 10 exhaust pipe diamaters from the engine, and there is no way to do this with factory exhaust. And placing it after the cats is a big faux pas...

    My gut tells me that since I'm mainly going to be looking at WOT the cats won't be doing much anyway. According to NGK, having the thing too close to the engine will skew it as much as 2 points lean, I'm guessing that putting the thing after the cats at WOT, the reading won't be skewed as much as trying to place it before the cats.

    Lastly, is there even enough gain to be had to do this? I've already leaned up the PE AFR, is the rest of the tune bad enough to warrant this?

    Thanks,
    Brandon

  2. #2
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    Use a narrow band o2 location for your Wideband while tuning the WOT

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    And yes, putting it after Cats is pointless because you will have incorrect readings

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    From NGK's manual:

    The sensor should be mounted at least ten exhaust diameters upstream of the exhaust exit (ex. for a 3” exhaust pipe, that is 30”). If the sensor is mounted between one and ten exhaust diameters from the exhaust exit, the AFR measured will be leaner than the actual AFR by as much as 2 AFR at low engine speeds (i.e. less than 3000 rpm).

    So, it seems to me either way you're screwed, since the NB is about 8" away from the engine.

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    I am not sure what the question is? The NB is 8 inches from the engine and at least 10 exhaust diameters from exit?

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    Quote Originally Posted by brandonleg View Post
    From NGK's manual:

    The sensor should be mounted at least ten exhaust diameters upstream of the exhaust exit (ex. for a 3” exhaust pipe, that is 30”). If the sensor is mounted between one and ten exhaust diameters from the exhaust exit, the AFR measured will be leaner than the actual AFR by as much as 2 AFR at low engine speeds (i.e. less than 3000 rpm).

    So, it seems to me either way you're screwed, since the NB is about 8" away from the engine.
    upstream - exit
    I read that as from tail pipe etc
    If you have 3" pipe, it must be Atleast 30"s upstream from the exit/tailpipe

    Use the NB or weld in a new bung.

  7. #7
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by brandonleg View Post
    From NGK's manual:

    The sensor should be mounted at least ten exhaust diameters upstream of the exhaust exit (ex. for a 3” exhaust pipe, that is 30”). If the sensor is mounted between one and ten exhaust diameters from the exhaust exit, the AFR measured will be leaner than the actual AFR by as much as 2 AFR at low engine speeds (i.e. less than 3000 rpm).

    So, it seems to me either way you're screwed, since the NB is about 8" away from the engine.
    key word - upstream

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    ahhh

    It's funny how the mind gets fixated on one thing - I was reading it wrong, taking it to mean exhaust exiting the engine not tailpipe.

    Thanks for beating me over the head on this until it sunk in.

    So, moving on now lol...

    Is it even worth doing on a basically stock truck like mine? Anybody done one of these and seen enough gain to justify the work?
    Last edited by brandonleg; 06-09-2012 at 06:49 AM.

  9. #9
    Senior Tuner Higgs Boson's Avatar
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    yes it is worth it even on a stock truck.