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Thread: Best way to change air/fuel ratio 16197427 $0D

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    Fuel Injected! Davis_1377's Avatar
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    Best way to change air/fuel ratio 16197427 $0D

    Wanting to run more rich for a bigger cam, what it the best way in tunerpro rt for 16197427 $0D to adjust air/fuel ratio? I know adjusting ve tabels but aint that corrected with the o2 sensor?

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    You running mostly stock? Any issues to make you want to run richer? Need more info. There are quite a few spots to tweak for that.... you could want a richer idle, richer startup, richer closed loop, richer open loop, richer PE/WOT, richer/longer AE if it's going lean on acceleration.... Need to know what's your goal or problem.

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    Fuel Injected! sturgillbd's Avatar
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    It is going to be in the O2 sensor parameters. You are wanting to target a different switchpoint for the O2 sensor. These are vs airflow for off idle and just target voltages for idle. You have a Lean, Mean and Rich for for idle and off idle. See attached screenshot.

    Brian

    Quote Originally Posted by Davis_1377 View Post
    Wanting to run more rich for a bigger cam, what it the best way in tunerpro rt for 16197427 $0D to adjust air/fuel ratio? I know adjusting ve tabels but aint that corrected with the o2 sensor?
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    Super Moderator dave w's Avatar
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    Injector flow is an option, well maybe? For example, lowering the injector flow from 61 lb hr to 59 lb hr makes the computer "think" it needs to ADD / INCREASE the "Injector ON Time" so more fuel is sent out of the injectors.

    Screen shots below are from 16197427 $OD VE Tuning using a plug-n-play AEM 30-4110. Measuring AFR is a GOOD THING!

    dave w
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    Fuel Injected! Davis_1377's Avatar
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    Quote Originally Posted by notime2d8 View Post
    You running mostly stock? Any issues to make you want to run richer? Need more info. There are quite a few spots to tweak for that.... you could want a richer idle, richer startup, richer closed loop, richer open loop, richer PE/WOT, richer/longer AE if it's going lean on acceleration.... Need to know what's your goal or problem.
    No im running a larger cam so i want to run it more rich where it should be for the cam.
    Last edited by Davis_1377; 06-15-2018 at 02:44 AM.

  6. #6
    Fuel Injected! Davis_1377's Avatar
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    Quote Originally Posted by sturgillbd View Post
    It is going to be in the O2 sensor parameters. You are wanting to target a different switchpoint for the O2 sensor. These are vs airflow for off idle and just target voltages for idle. You have a Lean, Mean and Rich for for idle and off idle. See attached screenshot.

    Brian
    Thank you, ill look into that, that seems like the best option.

  7. #7
    Fuel Injected! Davis_1377's Avatar
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    Quote Originally Posted by dave w View Post
    Injector flow is an option, well maybe? For example, lowering the injector flow from 61 lb hr to 59 lb hr makes the computer "think" it needs to ADD / INCREASE the "Injector ON Time" so more fuel is sent out of the injectors.

    Screen shots below are from 16197427 $OD VE Tuning using a plug-n-play AEM 30-4110. Measuring AFR is a GOOD THING!

    dave w
    That would work good, would the o2 correct it tho?

  8. #8
    LT1 specialist steveo's Avatar
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    an o2 sensor is only reliable when targeting a range near stoich (14.7:1 with normal gas).

    playing with o2 switch points might get you a 1% change or something which probably wont be noticeble, any further and closed loop will become unstable

    if you want to run richer than stoich during normal conditions you'll want to run open loop by preventing closed loop from being entered somehow (effectively disabling the o2 sensor) so your fueling changes are obeyed

    a good way to go would be to tune in closed loop so your VE table is correct, then disable closed loop and you can add a percentage of fuel. right now if you just throw fuel at it, it will be all over the place since your existing ve table is probably way off.

    if you want to run richer during acceleration but maintain closed loop during cruise, you're looking for the power enrichment tables

    No im running a larger cam so i want to run it more rich where it should be for the cam
    in my experience most cams are pretty happy with closed loop and 14.7:1 or so, just where do you think it 'should be'?

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    Fuel Injected! Davis_1377's Avatar
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    Quote Originally Posted by steveo View Post
    an o2 sensor is only reliable when targeting a range near stoich (14.7:1 with normal gas).

    playing with o2 switch points might get you a 1% change or something which probably wont be noticeble, any further and closed loop will become unstable

    if you want to run richer than stoich during normal conditions you'll want to run open loop by preventing closed loop from being entered somehow (effectively disabling the o2 sensor) so your fueling changes are obeyed

    a good way to go would be to tune in closed loop so your VE table is correct, then disable closed loop and you can add a percentage of fuel. right now if you just throw fuel at it, it will be all over the place since your existing ve table is probably way off.

    if you want to run richer during acceleration but maintain closed loop during cruise, you're looking for the power enrichment tables



    in my experience most cams are pretty happy with closed loop and 14.7:1 or so, just where do you think it 'should be'?
    Ahh i understand. I just heard bigger cams like more fuel but havnt tried it, i been tuning my ve tables for 14.7:1 so running more rich was something i havnt actually tried other then for a idle. I may stay with 14.7:1 then as it does run good.

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    Super Moderator dave w's Avatar
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    Quote Originally Posted by Davis_1377 View Post
    Ahh i understand. I just heard bigger cams like more fuel but havnt tried it, i been tuning my ve tables for 14.7:1 so running more rich was something i havnt actually tried other then for a idle. I may stay with 14.7:1 then as it does run good.
    I target the tuning for AE & PE for about 12.5 to 13.0 AFR. I target the VE tuning for idle and normal driving for about 14.7 AFR. I do not adjust the O2 parameter.

    dave w

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    LT1 specialist steveo's Avatar
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    Quote Originally Posted by Davis_1377 View Post
    Ahh i understand. I just heard bigger cams like more fuel but havnt tried it, i been tuning my ve tables for 14.7:1 so running more rich was something i havnt actually tried other then for a idle. I may stay with 14.7:1 then as it does run good.
    "it does run good" should be your main goal.

    really big cams (you know, the ones that barely make any power below 5000 rpm) like quite a bit more fuel outside of their operating range to compensate for crazy airflow patterns, you need the extra fuel to keep it from momentarily lean and stumbling all the time, but on these engines closed loop barely works anyway, emissions are out the window no matter what you do, and who cares because racecar

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