Air Intake Silencer Mod
This tech article was originally posted at FordF150.net. It is primarily intended for 1997-2003 Ford trucks but most likely also applies to other Ford vehicles.
This article was originally put together by Marc "BadAngler" Adams. I would encourage you to read the entire instructions before performing this. Enjoy. This is a relatively inexpensive modification which may increase air flow into the throttle body. If nothing else, It makes a cool sound.
Disclaimer: I made this mod to my truck of my own free will. If you make the mod and screw something up, don't blame me. Also, this mod was not my idea. I found out about it by reading an invaluable forum. I simply put pictures with instructions I gathered from the F-150 Online message board f150online.com.
This modification may void your warranty. If in doubt, check with Ford or your local dealer. Perform this at your own risk.
1. Disconnect the positive battery cable (this will reset the computer to adjust for any increase in air flow which may result from this modification). You will need a 8mm wrench for this.
2. Remove the throttle body cover by removing the three 10mm bolts. (One on passenger side and two on the drivers side of throttle body. Drivers side seen here)
3. Loosen the clamp holding the silencer assembly to the throttle body.
4. Remove the silencer assembly from the throttle body and then remove the two vacuum lines from the silencer assembly near the throttle body (the 2 tubes just below & to the right of the clamp in the above photo)
5. Loosen the clamp holding the silencer assembly to the air filter box and remove the the silencer assembly.
6. Rotate the silencer assembly so as to expose the intake air temperature sensor and unplug the sensor.
7. the entire silencer assembly can now be removed from the engine compartment.
8. Remove the AB flex connector from the silencer assembly by CAREFULLY inserting a long, thin blade screwdriver between the flex connector and the silencer assembly and carefully separating the two. (Caution should be taken during this step to ensure that the screw driver does not penetrate the rubber flex connector and the mechanics skin!!). This part of the process will take the longest, as the bond is quite good!
9. Using a Dremel tool with a standard cutting wheel, carefully make a cut inside the silencer assembly at the larger end. Be careful not to cut to deep or you may cut the outer housing. (See notes at end of article)
10. Make a second cut around the silencer to facilitate the removal of the silencer.
11. Carefully remove the silencer by grasping and twisting slightly to break the bond of the silencer at the small end. The silencer should just slip out.
12. Using the Dremel tool and a sanding barrel, lightly sand the cut on the modified silencer assembly.
13. Make sure to blow out the assembly to remove any cuttings which may enter the combustion chamber.
14. Apply a coating of black weather strip adhesive to both the inside of the flex connector and the modified assembly and reassemble.
Installation of the modified silencer assembly is the reverse of the above directions. Make sure the intake air temperature sensor is reconnected as well as the vacuum hoses and battery.
Webmaster's note: I performed this without using a Dremel tool. I simply pried and twisted the inner silencer with a pair of needle nose pliers. I have also had one report that you DO NOT need to remove the flexible part of the unit, but rather just need to cut it out from the end shown above.