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  1. #21

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    hahaha... wow, you are thick-headed...

    when doing around town/dity driving, you are not meeting the criteria long enough to either - #1-get into 4cyl mode at all, or, #2-if you happen to, it's not staying in it that long before it switches back to 8 cyl mode anyway... going into 4 cyl mode for 5 seconds then switching back to 8 cyl mode right away, isn't going to do **** for helping mpg...

    on the HIGHWAY is where it helps... long, steady driving, where it stays in 4 cyl mode for substantial amounts of time...

    ugghhh... I give up... you win....

    whatever...
    06MonteSS


    2014 Camaro SS - 2SS, RS pkg., short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake

  2. #22
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    Quote Originally Posted by 06MonteSS View Post
    hahaha... wow, you are thick-headed...

    when doing around town/dity driving, you are not meeting the criteria long enough to either - #1-get into 4cyl mode at all, or, #2-if you happen to, it's not staying in it that long before it switches back to 8 cyl mode anyway... going into 4 cyl mode for 5 seconds then switching back to 8 cyl mode right away, isn't going to do **** for helping mpg...

    on the HIGHWAY is where it helps... long, steady driving, where it stays in 4 cyl mode for substantial amounts of time...

    ugghhh... I give up... you win....

    whatever...
    If trying to understand flawed logic, is being thick headed, then guilty as charged.
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  3. #23
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    Quote Originally Posted by 06MonteSS View Post
    hahaha... wow, you are thick-headed...

    when doing around town/dity driving, you are not meeting the criteria long enough to either - #1-get into 4cyl mode at all, or, #2-if you happen to, it's not staying in it that long before it switches back to 8 cyl mode anyway... going into 4 cyl mode for 5 seconds then switching back to 8 cyl mode right away, isn't going to do **** for helping mpg...

    on the HIGHWAY is where it helps... long, steady driving, where it stays in 4 cyl mode for substantial amounts of time...

    ugghhh... I give up... you win....

    whatever...
    Just trying to understand myself, while what you say makes sense for city driving (that the AFM does not have the time to help your mpg) what I am not following is how there was an improvement by turning AFM off? I can follow how AFM does not help with city driving but how does it hurt you compared to staying in 8cyl mode all the time?
    Tony - Pittsburgh
    '09 Sierra SLT Crew 5.3L

  4. #24

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    I don't know enough about it to really know for sure but I'm wondering, since city driving causes a constant switch from 4cyl to 8cyl mode, if that constant switch (alone) actually decreases gas millage. Not to mention the fact that city driving is going to lead to decreased mpg anyway. Especially when compared to highway driving.

    So, I would imagine that in all actuality, the city driving was not effected by a difference in mpg (but was already naturally low) and highway drivers certainly saw a decrease in mpg by having AFM deactivated.

  5. #25
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    Quote Originally Posted by Vincennes02261897 View Post
    I don't know enough about it to really know for sure but I'm wondering, since city driving causes a constant switch from 4cyl to 8cyl mode, if that constant switch (alone) actually decreases gas millage. Not to mention the fact that city driving is going to lead to decreased mpg anyway. Especially when compared to highway driving.

    So, I would imagine that in all actuality, the city driving was not effected by a difference in mpg (but was already naturally low) and highway drivers certainly saw a decrease in mpg by having AFM deactivated.
    Possibly but again it doesnt make sense, I mean if you think about it this is like saying someone who is trying to lose weight and alternates between drinking a diet coke and a regular coke would actually lose less than someone who just drinks regular coke (everything else being equal of course). I mean if I would put my truck in neutral everytime I coast and when im sitting at a stop, would this hurt me gas mileage compared to keeping it in drive all the time...it does seem like flawed logic.
    Last edited by toleo; 10-11-2010 at 07:56 AM.

  6. #26

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    Haha.. I had to re-read your diet analogy a few times to get where you were coming from with that. But I follow you now. And I think you're right. If it's going to help you on the highway and not hurt you in the city, why disengage it altogether? You may not be getting improved mpg in the city, but you're not getting decreased mpg in the city by having it activated. Unless there is something regarding the AFM system that I'm missing here....

  7. #27
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    Ahhh Vincennes,& Toleo the voices of reason, & rational.
    I didn't want to get involved in Monte & Bears pissin match by asking this before, but what about being in 4 cyl mode when you're pulling a hill? What parameters does AFM use for determining how soon to switch back to 8 cyls?
    If it switches back too soon, mpg is lost by going back to 8. If it switches back too late mpg is lost due to speed loss & wasted fuel lugging it. How can this system be so precise as to know exactly what to do & when?
    1988 Chevy C-3500 2wd (no pic)
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  8. #28
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    Quote Originally Posted by stephan View Post
    Ahhh Vincennes,& Toleo the voices of reason, & rational.
    I didn't want to get involved in Monte & Bears pissin match by asking this before, but what about being in 4 cyl mode when you're pulling a hill? What parameters does AFM use for determining how soon to switch back to 8 cyls?
    If it switches back too soon, mpg is lost by going back to 8. If it switches back too late mpg is lost due to speed loss & wasted fuel lugging it. How can this system be so precise as to know exactly what to do & when?
    In your example I actually don't think anything is "lost". Keep in mind that the benchmark for all this is staying in 8 cyl mode all the time so I would look at it as perhaps "less gain" but even so its still better than staying in 8cyl all the time. Not sure if this really answers your question though, I will be the first to admit that the only thing I am 100% sure about is that I am not even close to being an expert on all this so in the end perhaps it is my own logic that is "flawed". I don't think AFM was designed to give you the absolute best gas mileage possible so must likely it is not that precise, perhaps its similar to a 4 and/or 6 speed transmission that moves to a lower gear when going up a hill which would mean your foot on the pedal would also have an impact on when this occurs, which sort of brings us full circle to the original analysis, my guess is that all things were not equal when Monte did his comparison (although in his defense he most likely tried to do every thing he could to keep it equal), I think other conditions probably impacted the results that he was finding when testing AFM on then turned off.
    Last edited by toleo; 10-12-2010 at 09:59 AM.

  9. #29

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    I have this AFM crap. Does any programmer out there allow for calibration of the AFM.
    Example: adjust Throttle position, RPM, calibrations.

    Just to throw my 2cents in:
    From my understanding from talking to dealer AFM is disabled if Throttle is +6% and/or RPM is over 1500 (almost exactly 45mph on my vehicle) as its for light driving condition only.

    Following this logic, how would AFM even help in hwy driving conditions? Just to show how pointless the factory calibration is,, in the city you are in alot of stop in go traffic, rarely do you get to steady your throttle position or rpm for more than a min, So really what is gains in city driving.

    I really believe GM has sold some very bad snake oil to people in regards to AFM

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  10. #30

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    As I mentioned in other post 98Hotrod98, both the Diablo trinity and Preditor can turn off the AFM/DOD.

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