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Thread: 3A92 aftermarket Camshafts

  1. #11
    Moderator Eggman's Avatar
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    In today's cars: change one thing, affect ten more.

    Older cars one change might have affected only five haha.


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        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.8 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


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    Quote Originally Posted by Eggman View Post
    A new cam is interesting. I wonder how that works with the Mitsubishi MIVEC variable valve control?

    No mention on whether it affects mivec operation from their Facebook post:

    https://m.facebook.com/Msracingcam/p...52383348406812

    More details on the cam specs on this post. Wonder how much power it makes on petrol though.

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    I just chatted with the people who produce the cams.
    They are running individual throttle bodies in place of the intake manifold plus e85 gives them maximum gains in power.
    Mivec operates as per normal and not disturbed.
    If anyone is interested they will be back in stock 15 nov onwards.

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    Moderator Eggman's Avatar
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    I have some questions.

    If MIVEC is built to respond to throttle input (variable valve timing according to engine load,) and the throttle is removed, how can MIVEC continue to 'operate as per normal and not disturbed'?

    Same with drive by wire operation - since the factory throttle body is controlled by the Engine Control Module (ECM) and the throttle body is removed, how does the ECM manage MIVEC control without knowing throttle position (different from accelerator pedal position) and fuel delivery?

    How is the accelerator pedal coupled to the three new throttle bodies and what feedback is provided to the ECM in order to maintain MIVEC operation?

    What happens to the fuel injectors?

    How does this affect spark timing?

    This goes beyond replacing the camshaft if the factory throttle body is replaced by individual throttle bodies. I expect there must be a kit of parts and ECM changes and/or delete too.

    There is more to this story.
    Last edited by Eggman; 10-22-2017 at 01:35 PM.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.8 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


  5. #15
    Senior Member MightyMirageMpg's Avatar
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    Eggman i read they are using a piggyback controller which step 1 of install is pretty much cut your engine harness in 2 and put computer in between. There's likely nothing factory about the fuel/timing/mivec maps.

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    Moderator Eggman's Avatar
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    Quote Originally Posted by MightyMirageMpg View Post
    Eggman i read they are using a piggyback controller which step 1 of install is pretty much cut your engine harness in 2 and put computer in between. There's likely nothing factory about the fuel/timing/mivec maps.
    Then I misunderstood what a 'piggyback' controller is. I thought the term 'piggyback' means it runs on top of and in conjunction with the existing controller.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.8 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


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    Senior Member MightyMirageMpg's Avatar
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    You are right that's exactly what it does. It gets installed in between the ECM and engine and intercepts/alters the signals

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    Quote Originally Posted by Eggman View Post
    I have some questions.

    If MIVEC is built to respond to throttle input (variable valve timing according to engine load,) and the throttle is removed, how can MIVEC continue to 'operate as per normal and not disturbed'?

    Same with drive by wire operation - since the factory throttle body is controlled by the Engine Control Module (ECM) and the throttle body is removed, how does the ECM manage MIVEC control without knowing throttle position (different from accelerator pedal position) and fuel delivery?

    How is the accelerator pedal coupled to the three new throttle bodies and what feedback is provided to the ECM in order to maintain MIVEC operation?

    What happens to the fuel injectors?

    How does this affect spark timing?

    This goes beyond replacing the camshaft if the factory throttle body is replaced by individual throttle bodies. I expect there must be a kit of parts and ECM changes and/or delete too.

    There is more to this story.
    I forgot to mention that when they say mivec is not affected it relates to a stock engine with the aftermarket cams only. With stock and running petrol they told me the gains are about 13% to 17% over stock cams.

    Valid questions regarding the throttle body setup. I also wonder how easy or hard it is to go that route.

  9. #19
    Moderator Eggman's Avatar
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    Quote Originally Posted by Fit View Post
    I forgot to mention that when they say mivec is not affected it relates to a stock engine with the aftermarket cams only. With stock and running petrol they told me the gains are about 13% to 17% over stock cams.
    But the ECM is programmed to deliver fuel according to the amount of air allowed through. If the air delivery is altered, the fuel delivery will need to be altered as well.

    If there is such benefit to this arrangement, why did Mitsubishi engineers not include this in their design?

    An engine can be built for power output or for efficiency and reliability. I am under the impression Mitsubishi chose efficiency & reliability over power. MIVEC already allows gains in both.

    Quote Originally Posted by Fit View Post
    Valid questions regarding the throttle body setup. I also wonder how easy or hard it is to go that route.
    It would require extensive modifications and expense. For a project car it would be fun and expensive though I think the expense would give greater returns spent on another platform. For a grocery getter, it would be a waste of money.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.8 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 59.7 mpg (Imp)


  10. #20
    Senior Member MightyMirageMpg's Avatar
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    The factory ecm can also add or subtract fuel for rich or lean conditions, right? (Top fuel has a nifty link regarding this)

    So like you said, your now filling the chambers with more air and the engines now running lean. The computer automatically adjusts for the added fuel like you said.

    But let's say your injector headway is small (i would presume the mirage uses the smallest injector possible at a high pressure for the most efficient atomization)

    If you have the ability to adjust +/- 10% duty cycle in open loop, you could install 10% larger injectors, and now have a +20 / -0% scale and your car would run like trash closed loop

    Back in the day it was common to "clamp" a map signal voltage, install larger injectors and run more boost in just about everything lol. That's why you would smell brand new (modded) cars running dog rich blowing black off idle but they were much faster up top

    The huge power gains made here is almost certainly due largely in part too huge timing advance allowed by the e85. The cam, itb's and whatever else is cherries on top.

    This setup might be great for racing (autocross in particular where the responsiveness of the ITBs would shine) but the economy would suffer immensely.



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