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Thread: MIVEC kick in

  1. #31
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    In Alex's post #2, watch the video. I guess that video could be from previous MIVEC systems. Or the *VIDEO* be depicting previous MIVEC systems (even though the video says it's the NEW MIVEC system).

    Halfway through the video, at the bottom, the words High lift, Low lift are there. And the valve is shown being PUSHED farther open in one versus the other. And the bell shaped graphs depict TIMING differences. For those that don't follow the graph (with bell shaped curves) so well, (I admit, I don't follow graphs and lines the first time I see them, I have to watch several times and really consider what the meaning is behind what I'm watching), the bottom of the bell shape curves (well, the whole curve too, but to more quickly understand, the bottom of the curves are easier to understand I think) show different points at which the curve moves up/off the horizontal, and then arrives back at the horizontal.

    The differences in the different colored bell shaped curves, in where along the bottom horizontal the bell moves up away from, and arrives back at the bottom horizontal represent valve timing change. The left-right location of the ends of the bell shaped curves. What it looks like is that the opening timing doesn't change much, or at all. But the valve closing timing changes more significantly.

    The overall distance the bell shaped line moves away from the bottom horizontal represents "lift."

    Based on the video, timing and lift are mechanically related. Based on the video, we do got variable timing AND variable lift.


    Last edited by 7milesout; 07-26-2023 at 08:47 PM.

        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


  2. #32
    That video shows a completely different engine. It may as well be an eco boost. The 1.2 doesn’t have rockers or rocker shafts.
    Attachment 25586

    Yeah that video is old and doesn't apply to the 1.2L whatsoever.
    This is a pic that Mitz posted a while back that seems to be the only post showing the actual engine.
    Attachment 25587

    And here's the town bicycle old tech that's been floating around for 10 years. Notice it has one camshaft. Our cars have two. But it's on the internet so....
    Attachment 25588
    Last edited by Fummins; 07-27-2023 at 12:35 PM.
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  3. #33
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    I guess I belong in the retardation chamber.

    I didn't even think about the fact that video was referencing a SOHC. I didn't think about that at all. I guess I was focused on trying to understand what it was showing....

    Is our valvetrain the sheeeeeim under bucket setup? I actually worked on that before, I pulled cams and swapped sheeeeeims out of a racebike (after measuring that they were out of tolerance).

    So timing only huh. Well, that blows my whole 68 mph theory out of the water. I'd like to avoid leeeeeift, but don't care to avoid valve timing changes. Valve timing is more delicious for mpg than is leeeeeift. But since we don't have leeeeeift, there's nothing to avoid.

    I'll go stand with my nose in the corner now. You can tell me when I allowed out.

        __________________________________________

        click to view fuel log View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.9 mpg (Imp)


  4. #34
    No shims, the actual lifter comes in different sizes. If you want to adjust you replace the entire lifter. They're stamped with different heights.
    I didn't catch the sohc part til today lol
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  5. #35
    Mirage videos:

        __________________________________________

        click to view fuel log View my fuel log 2014 Mirage SE wussie cvt edition. 1.2 automatic: 37.7 mpg (US) ... 16.0 km/L ... 6.2 L/100 km ... 45.3 mpg (Imp)


  6. The Following 3 Users Say Thank You to Fummins For This Useful Post:

    Basic (07-27-2023),craigq (07-28-2023),inuvik (07-27-2023)

  7. #36
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    I would like to add some of my findings regarding the increased power people are feeling at 3500rpm or wherever.

    From my data logging using an obd-2 dongle. I've noticed that this engine stays at 14.7:1 air fuel ratio at wide open throttle up until around the time that I feel the increase in power. This is when the afr jumps to around 13.0-13.5. This ratio is more ideal for power production in an NA engine, where 14.7 is the more chemically correct ratio for emissions and fuel mileage. Pretty much any fuel injected engine that I've dealt with from the 90s and 2000s pretty much switches to the richer afr any time about 90% throttle regardless of engine speed. Our Mirage seems to be aggressively tuned for fuel mileage and emissions at lower rpms. I have not looked into ignition timing at this time, but probably also changes as the ecu adjusts the afr.

    Keep in mind that this is strictly at wide open throttle. The air fuel ratio almoat always stays at 14.7 at all rpms when throttle is below 90% or so.



  8. The Following 3 Users Say Thank You to Pimp_Daddy_Patty For This Useful Post:

    BigMW (07-27-2023),Fummins (07-27-2023),inuvik (07-27-2023)

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