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25mm manifold and 12mm plenum spacer

Discussion in 'Mace Engineering' started by DevilDRake, Sep 8, 2010.

  1. DevilDRake

    DevilDRake Braaaap

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    Hey guys,


    I was wondering, How much difference would this make as in Dyno results, or take off (with roller rockers 1.98:1) ? My car i'll be getting will be dead stock, and with all of this + it being a manual and maybe 3.7-3.9 gears, would it be very quick changes also?

    AND will it fit under the engine cover??
     
    Last edited: Sep 8, 2010
  2. chevy_big_block_bro

    chevy_big_block_bro New Member

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    Well from experience I can say that you will notice a fair mid range gain with the rockers. Its not diff snapping power but its noticeable. As for the manifold spacer, Its bolted down to the top of the plenum so it will rise with the spacer if its the 12mm one but I cant speak for the 25mm one. IMO i'd take the engine cover off and polish the plenum lid.

    The longer runner length with the spacer did gain a little torque but your main benefit is the cooler plenum and therefor cooler intake air. I had a twin TB manifold on at the time when I fitted the spacer but there was still a small noticeable gain.

    The best mod you could do to the V6 is the diff gears. That will show the most results when it comes to takeoff
     
  3. DevilDRake

    DevilDRake Braaaap

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    Yeah i know about the diff gears, I've got a list of Dif gears + manifold 25mm + 12mm spacer + throttle body + 1.98:1 rockers.

    I just wanted to know if they'd fit under a engine cover as i'm a p plater.
     
  4. old mate

    old mate New Member

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    yep, will fit under the engine cover.
     
  5. MACE

    MACE Well-Known Member

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    Hey DevilDRake,

    In regards to your questions/statements…

    “I was wondering, How much difference would this make as in Dyno results, or take off (with roller rockers 1.98:1)?”
    The spacers won’t improve a great deal top end (couple of kws) where they really shine is down low, by they I mean they can improve low end torque by around 15% which is definitely noticeably on the road and track.

    “My car i'll be getting will be dead stock, and with all of this + it being a manual and maybe 3.7-3.9 gears, would it be very quick changes also?”
    Given it’s a manual the shortest I would probably go would be a 3.7:1 gear ratio.

    AND will it fit under the engine cover??
    You best bet would be to take a couple of measurements just to make sure as every car is different; fitment summary from experience for your car is as shown below.

    • Raising manifold by 12mm: Cover will go on like factory
    • Raising manifold by 25mm: Cover will need to be trimmed around the alternator or bonnet liner needs to be removed or trimmed. Otherwise cover will rub on bonnet liner
    • Raising manifold by 37mm: Cover will need to be trimmed around the alternator and other parts along with the bonnet liner needing to be removed. Otherwise cover will rub on bonnet liner/possibly not close depending engine mounts
    • Raising manifold by 50mm: No hope of keeping cover without some serious bonnet mods. Will still require bonnet mods without cover
    Hope this helps :)

    Cheers
    Steve
     
  6. DevilDRake

    DevilDRake Braaaap

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  7. MR_VX

    MR_VX Forced to be Fast

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    would it have any effect if the motor is supercharged ??????
     
  8. TI3VOM

    TI3VOM Active Member

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    It sounds like you have it around the wrong way the longer runner length is what made the difference not the insulating properties of the manifold. The air in an engine never sits there long enough to heat up.
     
  9. habs420

    habs420 New Member

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    i got the 25mm plenum the other day, very noticable in the low end!
     
  10. DevilDRake

    DevilDRake Braaaap

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  11. MACE

    MACE Well-Known Member

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    These work well on NA, turbocharged and supercharged cars, as shown in the link below.

    http://forums.justcommodores.com.au...3-manifold-spacer-ecotec-wow.html#post1643637

    The insulating properties do help but the main reason is because of the increase in runner length.

    Glad you’re happy with the gains Rhys :)

    If habs420 is in fact who I think it is then he got the 25mm manifold insulator otherwise I just looked like a goose LOL :p
    Cheers
    Steve :D
     
  12. DevilDRake

    DevilDRake Braaaap

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    Haha :D. i'm looking forward to these, just gotta sell my ute and get the car first ;D
     
  13. menace2sobriety

    menace2sobriety New Member

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    25mm Manifold Insulator and 12mm Plenum Spacer fitted the other day, took roughly 35 minutes all up ( no dicking around ) + a bit longer to let the GOO set, no need for instructions, everything is very basic

    Now at idle with the bonnet open the whole plenum is cool to the touch even when the engine is hot-hot, obviously with the bonnet closed this heats up but is still a lot cooler than the intake

    Bottom end torque has increased and has also seemed to increased throughout the entire rev range, if I have the wheels on any angle while taking off with anything over quarter throttle it will start to spin the wheels

    No modification was needed for my bonnet

    Quick and easy mod to do, for the extra low down torque you pick up, it is worth the money

    Cheers
     
  14. MACE

    MACE Well-Known Member

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    Thanks for the constructive feedback menace2sobriety. Glad to hear you're happy with the products

    Best Regards,
    Steve
     
  15. aza03

    aza03 New Member

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    I had these spacers on my vy they are great well worth the money
     
    Last edited: Mar 6, 2012
  16. HoldenOn

    HoldenOn New Member

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    im considering picking up a plenum spacer and manifold insulator next week for me n/a ecotec. Would a 12mm spacer and 12mm insulator be a good mix? or should i go 12mm spacer and 25mm insulator?
     
  17. MACE

    MACE Well-Known Member

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    Hey HoldenOn,

    An ideal combo would be a 12mm plenum spacer and a 25mm manifold insulator, if space or budget permits. Otherwise you'll be happy with a 12mm plenum and a 12mm insulator

    If you have any more questions please don't hesitate to ask.

    Cheers,
    Steve
     
  18. mr calais 5.0

    mr calais 5.0 New Member

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    Sorry to dig deep and find a old thread but is there much difference between 12+12mm and 12+25mm spacer set up? Looking to order 12 plem and 12 manifold or 25 manifold spacer.. Prob in the next 2 weeks and maybe a cold air intake as well..
     
  19. vyseriesII

    vyseriesII The Blessed Hellride

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    Better to 12mm plen and 25mm insulator. Other way round for supercharged engines. But in saying that, i run 12mm plen, 25mm insulator and its now supercharged and i have no issues.
     
  20. mr calais 5.0

    mr calais 5.0 New Member

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    Cool thanks for the help.. Not looking to charge it for a while yet but 1 day maybe.
     

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