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cf Airbox leverweight > gasket damge

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  • cf Airbox leverweight > gasket damge

    As there are interesting discussions about tubing, mounting etc,
    Im asking me i if I am alone in the field with some
    sealing problems on the connection from the throttlebodys to the head after driving a cf Airbox for ~1000km

    I saw that the original plenum was supportet on a mount, wich derives the force from the plenum.
    The cf Airbox now is only connectet to the throttle bodys, wich are connectet to the head.
    To eliminate these forces & oscilations and to preserve my gaskets, I worked out a "force-connector"
    to link up the forces.

    Did you make some experiences and/or worked something out ??


  • #2
    It's sort of ironic if you think about it, one of the main reasons some go to the c/f airbox is to reduce the tendancy of the throttle body gaskets from failing, I figured that there was a separate support for thr "body" of the unit, but the one you made up looks great.


    • #3
      I haven't run into any sealing issues. The CF intake is quite light compared to the stock metal plenum. Between the intake and the TBs are o-rings, at each port. You could add some nondrying sealant if you really wanted to do so. Additionally , there is no need for a super vacuum tight connection as there is no longer any need to create vacuum to make the AFM door to open. In fact there is no real vacuum created in the intake as restiction is so low. There would be some though due to air pulsation and the like. Is the cantilevered weight enough to create leaks at the TB to head area? That's a good question, but in my case it appears to be a nonissue.

      When running A-N, you can only find significant vacuum between the head and the engine side of the throttle blades. Any leaks in any location won't affect fueling as the engine is running off of the position of the throttle shaft. Leaks near the head/TB junction can let in some unfiltered air though, but not much.

      In a stock motor, the vacuum extends from the head to the AFM. It's different before and after the throttles though. BTW the stock plenum can hold about 2 gallons of air, so that is a lot of low pressure air! And part of the sluggish throttle response in high specific output AFM cars. Also, any leaks throw off the AFM's output. Even small leaks are anethama to proper fueling, making the motor run too lean.

      You could also run a brace to the TBs instead if you wanted a steathier install.



      • #4
        Originally posted by Stan

        You could also run a brace to the TBs instead if you wanted a steathier install.

        Thanks for the input Stan,
        -I will fabricate a brace that goes to the TB....:idea:

        my toughs are that vibratons may loosen screws, washers etc, at least the hole airbox thing while driving on the Autobahn. :rolleyes:

        The other "vibration victims" are the Ignition coil conection and one
        Alternator brace. bzzzzzt.

        Last edited by ///M-fart; 01-04-2004, 04:46 AM.


        • #5
          Mine has been fine, the CF box is almost like not running anything on there! I can 't see how it would ruin ht gasket seal.

          But as Stan stated, it really doesn't matter with A/N, but unfiltered air is not all that great either.

          Do not click
          At least it's German


          • #6
            I gotta say this, that is one snazzy looking brace you made....


            • #7
              Daniel did you install some brand new gaskets? die you
              use silicone sealer?

              I havent had any leaks either.