Free Ram Air Modification

Tools you will need:
Saw or Dremel Tool
  • Sand paper; 200 plus grit
  • 10 mm socket
  • ratchet
  • 3" extension
  • Circa July 1999
    Car: 1999 Z28 Camaro, 4,200 miles
    Eric and Kelly Barger
    People who helped us from major tech talk to general advice:
    Elmer Boggs (
  • All my buds at

  • Expect approximately 20 – 40 minute install time 
    When purchasing, viewing, using, and/or any other method applied to this publication you agree to the following statements.  You, your next of kin, heirs or assigns release, all other persons associated in the making, production, participation, and sale of this publication.  Rephrased in plain English:  When you purchase this CD, book, or view this web page you, your next of kin, heirs or assigns agree not to sue any associated persons with the publication for any accident or damage in ANY form (mental or physical to your car and/or yourself) because of this publication or your failure to heed proper safety, maintenance and/or modification procedures.  You also agree that your next of kin, heirs or assigns cannot sue all persons associated in the making, production, participation, and sale of this publication.  
    Perform all these installs at your own risk.  Know how to use all of your shop equipment and take necessary safety precautions when performing ANY modifications and or maintenance items to your vehicle.  Seek the advice of a paid professional and do not substitute this publication for the advice of a paid professional.  This product is how we accomplished our installs and is not meant to be carved in stone.  We are not responsible for a mistake, misprint, or any other error found in this guide.  This guide is intended as a supplement and not to be your only source of information.

    Purpose:  This modification will remove most of the bottom plastic on the bottom of the air box.  This will decrease the air temperature significantly giving your car some extra horsepower and better air.  Expect your air filter to get dirtier a lot quicker than usual with this modification.
    Reminder:  Make sure you have the keys out of the ignition.  Why?  When you remove the sensors from the air box lid assembly you do not want to start the car.  You will set the Service Engine Soon (SES) light.  If you do start the car without placing the sensors back in you can easily reset the SES light by following these steps:
        1.  Turn key to the "on" position but don't start car     2.  Pull the PCM BAT and PCM IGN fuses in engine compartment     3.  Wait approximately 5 minutes     4.  Turn ignition off     5.  Replace fuses     6.  Start the car and then make sure the light has gone off
    1.  Open the hood of your car and look in the front and center of the engine compartment.  Locate the air box lid metal clamps (see blue arrows in Figure 1)
    Figure 1

    2.  Go ahead and undo the air box metal clamps (see blue arrows in Figure 2).
    Figure 2

    3.  Now you will have to remove the two plastic pushpins that hold down the air silencers (see blue arrows in Figure 3).  Refer to Figure 4 for the three-step process to remove a pushpin:
    A.  Locate the pushpin on the driver's side of the air box assembly.   B.  Place a flat-head screwdriver underneath the head of the pin while holding down the "collar" portion with your thumb.  C.  Pull pin up and remove.
    Make sure to keep the clips just in case you need to replace your factory air box lid for a trip to the dealer or other need.  If you do break the clips they come in packs of ten (10) and are really cheap.  The GM part number is 12551599.
    Figure 3

    Figure 4

    4.  Locate the intake air temperature (IAT) and mass-air-flow (MAF) sensors (see blue arrows in Figure 5).
    Figure 5

    5.  Remove the two sensors from the air box assembly shown in Figure 5.  You can see an example showing how to remove the sensor connectors safely in Figure 6.  Gently pull the tab out and lift the sensor out of the housing.  
    Figure 6

    6.  Go ahead and locate the rubber flexible hose that runs from the mass-air-flow housing (MAFH) to the throttle body (TB) (see blue arrow in Figure 7).  Take a flat-head screwdriver and loosen the metal clamp.
    Figure 7

    7.   Grab hold of the air box, lift and pull towards you (see Figure 8).
    Figure 8

    8.  Pull out your air filter and then locate your lower air box assembly (see Figure 9).
    Figure 9

    9.  Remove the tray that sits in the lower air box assembly (see blue arrow in Figure 10).
    Figure 10

    10.  You will use a 10 mm socket and ratchet to remove the four (4) screws that hold the lower air box assembly down (see blue arrows in Figure 11).  
    Figure 11

    11.  You will need to cut the air box around the edges of the inside (see dotted blue line in Figure 12).  You can use a Dremel tool or a hand saw (use a fine edged blade).  Just take your time and be careful.  After you cut the air box you might want to sand down the cut edges.  This just makes the cut look better and gives it a sleeker look.
    Figure 12

    12.  Take a look at the air box after it has been cut in Figure 13.
    Figure 13

    13.  Once you have cut the air box you need to cut the plastic air baffle below the air box.  Locate the plastic baffle (see blue arrow in Figure 14).
    Figure 14

    14.  Place the lower air box assembly you just cut back on the car.  Draw an outline on the baffle against the lower air box edges that you just cut.  That way when you remove the lower air box assembly you can see where you need to cut.
    15.  We suggest using a Dremel tool to cut the baffle.  Just be careful and take your time.  You might want to sand down the cut edges when you are finished to clean up the look of the edges.  See Figure 15 below to see what the cut looked like on our baffle.
    Figure 15

    16.  Now you need to reassemble everything.  When placing the lower air box assembly back on, you will need to make sure that you get the rubber supports (back corners) of the lower air box on the radiator shroud (see Figure 16).
    Figure 16

    17.  You now need to replace the four (4) 10 mm screws back in the lower air box (see Figure 17).  We just tightened the screws to "snug".  No need to really tighten them down.
    Figure 17

    18.  Place the air filter tray and air filter back into the lower air box assembly.
    19.  Grab hold of the air box lid (refer to Step 7) and push the rubber boot back on the throttle body.  Make sure you get the rubber boot all the way back on the throttle body.  Then tighten the metal band clamp on the rubber boot (see blue arrow in Figure 18).  
    Figure 18

    20.  Reconnect the wires to the IAT and MAF sensors (see blue arrows in Figure 19).  If you do not you will get the Service Engine Soon (SES) light on your dashboard.  No big deal but it is nice to avoid the hassle if you can.  If you do set the light you can reset your PCM by using the steps mentioned above in the Reminder.
    Figure 19

    21.  Reconnect the metal air box clamps and you are set!
    Comments: At the time we completed this mod we had no other performance modifications.  We could tell a  noticeable difference in throttle response and additional horsepower.  We experienced a slight "whistling" type sound from time to time.  Don't worry about that sound if you experience it.  The sound occurs because we removed the silencers on the air box lid assembly.