What does it do?

 

It is a "resonator".

Not exactly like a muffler, which reduces sound, but rather a resonance chamber that creates and intended sound frequency to cancel out others.

In other words, it used to make the intake surge when heavy on throttle sound like whoosh rather than vrooom. Creates that vacuum cleaner sound so Soccer Moms don't scare themselves when they pass the ice cream truck.

It does so by colliding intake air pressure waves into each other, cancelling out the unwanted "noise" leaving what the engineers' deemed as a more desirable sound. The process reduces intake efficiency in order to create the OEM desired sound.

Simply put, it chokes out some sound at the expense of optimal performance.

 

And you can get rid of that OEM sound by installing an Air Doc cold air intake ;-)

 

You can do the same thing by cutting the resonator off and then covering the hole with plastic, without spending big bucks on the Air Doc.

 

Thanks for the explanation Doc Olds

650Hawk, not a bad option but my engine bay doesn't look like that.

 

You have the I5 then. Don't worry, there are options for it too

 

i once experimented with a piece of rolled sheet aluminum to fit inside, from the input side to the output. nice smooth passage, blocking the res chambers!
no charge!! stock appearance.

 

[QUOTE=650Hawk;343378]You can do the same thing by cutting the resonator off and then covering the hole with plastic, without spending big bucks on the Air Doc.

No thanks, I'm happy with the AirDoc and it doesn't look like it was modified in a third world country.

 

You "could" do this also, but I'd rather have Air Doc CAIs on our Alphas.

 

[QUOTE=RealJeep;343389]Seriously? Well, I disagree that mine looks "third world", and the Air Doc, IMO, is way overpriced for what you get, but hey, it's your truck and your money.

I actually did the mod for access purposes, not noise/performance. I was chasing down a wiring issue, and the resonator completely blocked access to the top of the engine. Removing the intake/resonator would not allow the engine to run since the MAF was no longer in "the loop". Cutting the resonator off allowed access to the problem writing while the engine was running.