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25mm top and bottom spacers

Discussion in 'Mace Engineering' started by daniel199260, Aug 19, 2016.

  1. daniel199260

    daniel199260 Member

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    I know a lot of people run 12mm plenum spacer and 25mm manifold insulator, but have not seen or read of anyone running 25mm top and bottom? Wondering what the go is there. Is it do able or?
     
  2. commodore665

    commodore665 expat Saffa

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    that combination would work best only in forced induction , IE supercharged or turbocharged , you'd lose to much bottom end torque otherwise .
     
  3. MACE

    MACE Well-Known Member

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    Hi daniel199260,

    Thank you for your enquiry.

    "I know a lot of people run 12mm plenum spacer and 25mm manifold insulator, but have not seen or read of anyone running 25mm top and bottom? Wondering what the go is there. Is it do able or?"
    The reason is that for NA (naturally aspirated) applications, ideally you would want to run a 25mm manifold insulator and 12mm plenum spacer. Otherwise, if you're running some form of boost, we would recommend a 25mm plenum spacer and 12mm manifold Insulator as the thicker plenum spacer offers even greater air distribution between cylinders when dealing with greater air flow. On this note, if you attempt to run a 25mm plenum on a NA ecotec, it will impair driveability and performance.

    If you have any other questions, please do not hesitate to ask.

    Kind Regards,
    Michael
     
    steve. likes this.
  4. 1997 VT Calais Series 1

    1997 VT Calais Series 1 New Member

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    Just not a good cobination, it also implies that you need to add or make other changes to your sytem? Like a larger throttle body or twin throttle body, I did read somehwere that adding a larger throttle body fixes the issue with the 25mm top and bottom, but why I don't know?
    I think the standard throttle body opening is not large enough and it is choking the airflow, but that is just a guess. Common sense tell me that if you add a larger throttle body more air will be allowed to flow and thus fixes the issue.
     
  5. MACE

    MACE Well-Known Member

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    To further add to what 1997 VT Calais Series 1 has written, basically, the larger throttle body, fills up the larger plenum chamber volume quicker than the standard throttle body.
     

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