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Air Intake Duct R170 4 Cylinder.

Discussion in 'General Mercedes-Benz Related Discussion' started by RhodiBill, Sep 10, 2019.

  1. RhodiBill

    RhodiBill Senior Member

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    Your Mercedes:
    Mercedes 2003 R170 SLK230K
    I have a question concerning the size of the Air Intake Duct that sits behind the Grill of the 4 Cylinder R170 SLKs.

    I noticed when doing my Grill that the Air Intake Duct that sits behind the Grill that feeds the Airbox is, in my mind, absolutely tiny compared to the Tubing behind that leads to the Airbox and the rest of the Intake Piping.

    Unfortunately I did not take a photo myself but have found a Generic one that will serve for the purpose of illustration.

    It measures approx 4cm across by 6cm high whereas the rest of the piping is approx 8-9cm in diameter! Surely this cannot be right? I liken it to breathing in through your nose with one side blocked - not good!

    Every other Mercedes and other cars where there is an Air Intake behind the Grill might not be exactly round but is more or less a similar overall area as the rest of the Tubing it feeds.

    Please enlighten me someone as to why this is?

    To be honest I was contemplating removing this and just extending the Pipe it connects, (which is easily twice its size) out to the same point.

    [​IMG]
     
  2. OP
    RhodiBill

    RhodiBill Senior Member

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    Mmmmmmm. 36 reads and no opinions...??? Come on, one of you must have had done Physics at school - you know, that big building with lots of windows and screaming kids and a Deputy Head walking the corridors with a cane!! :D
     
  3. LostKiwi

    LostKiwi Senior Member

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    Probably something to do with accelerating air into the filter box. Air drawn through a smaller orifice travels faster gaining inertia in the process. That inertia can be used to create high pressure zones on the top of the filter element. Even at 4x6 it's bigger than the exhaust.
     
  4. OP
    RhodiBill

    RhodiBill Senior Member

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    Your Mercedes:
    Mercedes 2003 R170 SLK230K
    I would understand that if it was feeding directly into the throttle, like a venturi, but it isn't. And seeing as there is about 300mm of piping with 2 bends, then a filter followed by quite a bit of piping and other paraphernalia, then a supercharger followed by more piping, intercooler, more piping before it gets anywhere near the throttle body, that theory just doesn't hold water I'm afraid....

    But even if the aperture was an exact rectangle, which it isn't, the area of the aperture is almost a 1/3 less than the exhaust. (I measured it).

    Anyway, I have removed it and extended the pipe that that joined on to with a slightly funnel shaped one of the same size of my own.

    Thanks anyway for the input - appreciated. :)
     

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