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Installing CF airbox...description

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  • Installing CF airbox...description

    Ok guys, Im getting a bit bombarded with
    install questions. We should probably supply
    very detailed install instructions with pictures,
    step by step. I apologize for the inconvenience.
    As with many things in life, its really easy once
    youve done it atleast once.

    instructions on how to install the airbox:

    -- remove the old plenum, runners and airfilter housing
    together with the AFM. remove the snorkel
    protruding thru the front frame. now is a good
    chance to clean up the area if it needs cleaning.
    remove any strut brace.

    -- rotate dipstick forward toward the alternator.
    be careful not snap it off at the base! It will be
    a PITA if you snap it.

    -- take the PS resevoir bracket and rotate 180
    mount it onto the airfilter-housing support.
    you may do some trimming to length if desired.
    some people also just make themselves a new
    bracket. This will move the PS resevoir forward
    and out from the airbox.

    -- decide where you would like to have the
    new brake fluid resevoir mounted. Most
    people mount it onto the strut tower. It needs to
    be mounted away from the airbox.

    cut brake hose to appropriate length (supplied)
    to run from the master cylinder to your new
    brake resevoir mounting position (on strut tower).

    remove the old brake fluid resevoir from the
    master cylinder. install the 2 new rubber
    grommets (supplied) into the master cylinder
    ports. install the 2 90-deg plastic elbows
    (supplied) into your brake hose and then insert
    into the master cylinder.
    The rubber grommets provide the seal.
    connect the other ends of brake hose to the
    new brake fluid resevoir.

    you may reuse your old resevoir cap which
    has a floater. if the new resevoir is not mounted
    to far forward you can hook up the cable again
    (low brake fluid indication).

    -- cut the ICV hose near the T-junction (do not
    cut off the T). mount the airbox and measure
    the length of hose you need to splice in
    between the ICV and the forward airbox port
    (there are 2 ports located underneath the
    airbox). Newer kits have a different hose
    supplied with some different splices, but the
    procedure is the same. The curved end of the
    hose goes onto the airbox port.

    Use the supplied clamps to clamp either end
    of the splice and to clamp the hose to the airbox

    The goal is to get the hose running horizontally
    between airbox and ICV without any kinks in
    the hose.

    You should have some short length of hose that
    is left over as the supplied hose is longer than
    necessary. You need this in the next step...

    -- Splice on the short length of hose from above onto
    the oil separator hose. The oil separator hose
    runs from the oil separator to the rearward port
    on the airbox. With the airbox mounted
    measure the length of splice that you need.
    Make sure that the hose is not kinked --
    if you stretch the hose too much it will kink near
    bottom at the oil separator port.

    Some of us dont use the rear port. It gets
    capped off (Jimmy convinced me of that).
    Reason: no blow-by gases get recirculated
    into engine intake and it is not possible
    to "burp" oil into the airbox, should the oil
    separator act up. Besides, there is really
    no vacuum in the airbox to speak of as
    the airbox is in front of the TB plates and any
    vacuum is behind the TB plates.

    If you intend to do this, then get yourself
    a tiny K&N airfilter, cut the oil separator hose
    to an appropriate length, install K&N into hose,
    mount the K&N somewhere appropriate.
    The K&N should have a stud with nut on the
    top. I just mounted mine in horizontal
    position right to the oil dipstick bracket, so
    it is only a short length of hose from oil
    separator to the dipstick bracket.
    Some prefer to mount theirs in vertical position.
    If you use some silicone spray on the inside
    end of the hose, you can insert the K&N with
    ease. The silicone disappears and leaves you a
    tight press fit.

    -- now mount the airbox and torque the acorn nuts
    the kind with washers underneath.
    just moderately more than finger tight.
    7-10 Nm is more than sufficient.
    if you use a short ratchet you
    are less likely to overtorque. Connect all
    the hoses and tighten the clamps.

    the throttle cable braket obviously goes under
    3 of the acorn nuts. Mount your old throttle cable
    bracket (remove from plenum) on top of the
    new one (supplied). Adjust play in throttle cable.
    Make sure other end of throttle cable is firmly
    seated in the firewall (you may have pulled this
    out). If your cable is old with worn grommets,
    you may just want to buy the entire cable new.

    NOTE: Before the airbox is mounted, you have
    the chance to confim that when you push
    on the throttle lever (not the pushrods!)
    that the throttle plates (butterflies) are
    horizontal when the TB stop is engaged.
    (there are measurements for correct distance
    above and below the butterfly when in the
    WOT position-->search). You can also
    check with a dial guage that you have
    0.15 mm opening in the idle position. If anything
    if off, its time to make adjustments to the TBs.

    With airbox mounted: confirm that when the
    gas pedal is in the WOT position, the throttle
    lever contacts the throttle stop. If this is
    not the case, your throttle cable requires further
    adjustment or the screw under your gas pedal
    is misadjusted. Properly setup: later when
    alpha N is installed and you do the TPS adjustment
    you should be able to see a TPS reading of
    12% at idle position and 94-96% at WOT
    (tested with alpha N online and engine off).

    -- now you can mount the snorkel to the
    front frame and install the large 120 mm diameter
    airhose between snorkel and airbox.
    I tape my airhose. Some people use band clamps.

    -- if you have a CF airfilter housing which mounts
    inside the front bumper, there are additional steps
    before mounting the snorkel. In brief:

    remove front bumper

    relocate the electric fan toward the passenger
    side (2-3 cm). I did it the easy way: rotate
    fan 90 degrees and bolt thru the frame. I
    used rubber isolators. Then I re-bent the top
    mounting brackets appropriately. Of course,
    if you have an electric puller fan, then this is
    a non-issue.

    I used sealing tape between CF airfilter housing
    and front frame wall and also between snorkel
    and frame wall. Bolted thru frame wall using
    2 bolts (drill and paint to prevent rust). Clean
    the area well so you get a nice seal.

    You have to also drill the appropriately located
    holes into the CF snorkel, because the snorkel
    is bolted from the engine bay side thru frame
    into the CF airfilter housing.

    On the right side of the airfilter housing are
    3 threaded fittings -- just bolt the CF snorkel
    straight into the airfilter housing (there is no
    frame inbetween as this is open space next to
    radiator). Sealing tape is used between these
    two pieces.

    To get the airfilter housing in position, slide
    housing in sideways with out any filter attached.
    Bolt it all together with the snorkel, then insert
    the filter and lock it down with the top plate.
    Dont torque the top plate too much or youll
    just squish the filter gasket.

    It is helpful if you pull the radiator up and tilt
    it away toward the engine to gain easier
    access during install.

    Try to get the snorkel mounted HIGH because
    once its in position, you will see there is not
    too much clearance to the power steering pump.
    Also, when it is mounted high, it should be in
    a straight line with the airbox intake when viewed
    from the rear or from the side. If its not lined up
    the snorkel hose will look a bit kinked.

    anyway, once finished you should have
    airfilter housing-->seal tape-->frame-->
    seal tape-->snorkel and all of it should be
    very flush.

    If you prefer, you can install a deflector
    shield (not supplied) next to the CF airfilter

    NOTE: I use a M3 K&N panel filter of stock size
    (roughly 18 cm by 32 cm). Dont over oil it
    as the excess will just get all over your airbox.
    With the filter located in this position, you will
    have to clean it more often. I clean about twice
    per year, but this depends on your usage.
    You dont have to worry about the rain.
    The filter will get wet, but it causes no problems
    with your airbox or engine and does not
    effect engine performance.

    As a final touch, install the "BMW Motorsport" logo
    on the airbox (not supplied).

    I hope this helps. If you still have questions, email
    me as always.


  • #2
    here you go...


    • #3
      I had no idea it was so much work to fit one of these. What about the 320is cars which dont have the M3 front end?


      An[email protected] | H23-is | S14 | Ceccoto #270


      • #4
        I have not worked on a 320is. you would have to post up some pics with the bumper removed
        so I can see it.

        the airbox install is not that hard, it just sounds like a lot to do. I can take my airbox off
        in about 3 minutes and reinstall it in about 5.



        • #5
          It most likely took you longer to write this up then to R&R your airbox !
          Thanks a lot for the post this will be helpfull for all the guys that just bought the CF airbox.

          Thanks Thomas


          • #6

            If you get a chance Id get some pics up. Just helps when visualising.

            Good description though.


            • #7
              well, if any of you guys would like to snap a few pics while you install and post here that would be
              nice. I dont have any install pics unfortunately. the only think I could do is remove my airbox
              snap some pics and install it and snap a few more. all the hoses are already cut and in place
              so you wouldnt really see what was done on install