what is the purpose of this plenum or whatever it is called hanging off the bottom ? This is the duct that runs from the air filter box to the throttle body on an 8.1L in a 2006 Sierra. I mistakenly got a duct for the 6.0L gas engine which is slightly different shape but that also has a plenum thingy hanging off it.
I am going back to oem configuration on the truck. It came with a K&N cold air kit- cone filter replaced the air box and the K&N duct was just a straight pipe that went from air box & MAF sensor to the throttle body.
So my question is how come the OEM setups have this plenum thingy, what is it's purpose? And why does the K&N setup not have it?
I think the national anthem ought to be sung in English, and I think people who want to be a citizen of this country ought to learn English and they ought to learn to sing the national anthem in English.
It can be used to "silence" or to just cancel out frequencies that are annoying, or to give a cool power sound at WOT (wide open throttle) in the higher rpm ranges.
My gues is all of the above for the one pictured.
FWIW, the principle is the same one CORSA uses on their mufflers to tune the sound.
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