Question about CAI

Can anyone tell me why on earth what looks like a motorcycle catalytic filter would be in the throat of a K&N CAI? My son just bought his first Mustang and took the filter out to clean it and found this in the throat

That's an air straightener, many new cars use them in the induction tubes. I think it's to make the air less turbulent for the MAF sensor but I can't remember.

edit: Guess I was totally wrong! I couldn't remember.

some early mustangs had this in the intake hoose, sound damping I think, and you can live with out it and maybe get 2 hp extra.

regards Mats

It's actual function is to absorb unburned hydrocarbons that evaporate into the intake tube after the engine is shut down. The early 4.6 3V cars had it in the stock intake tube and any aftermarket intake installed on those cars needs to have it transferred over to be CARB legal. Ford managed to find a way to pass emissions without it on the later cars. Do a search for "2005 Mustang hydrocarbon trap". There are plenty of owners who have removed it with no problems.

Thanks everybody I had never seen this before and I have an 06 and an 07. We did remove it cause when I looked at all the CAI kits on Summit's web site not one of the 54 listed had this part. so I figured it wasn't needed.

I'd suggest getting the car tuned without that in the CAI. These cars are very sensitive about the CAI's.

If you decide to go HPTuners for tuning let me know and I’ll walk you through setting your car up for your CAI.