Wow. resurrecting a 2.5yr old thread..yikes.
It's just you..lol

2 posts above yours....

 

Wow, everyone would just like to be heard 02 Ram... If you don't have something good to say, say nothing... If you want to talk about physics (to sound socially smart) you would have noticed I have a 4" to 3" reducer at the intake and the filter. So physics as you so speak about would prove that when you bottle neck something from two ends you cause a vacuum effect thus creating more volume of air to be pulled though the tube. Soooo if you would still like to disprove this theory Mr. 02ram, go do some research. Or go back to school. Only thing you had right is it does cost more for 4" PVC, but for me it was like a whole 4 bucks for me here where I live. big deal. I still have this mod on and it has proven itself over and over.
Dirty dog is right, it is not necessary to go to 4". He is also right bigger is not always better. There is a limit and I would say 4 is nearing that. However to disprove your theory of not having enough flow going to big, take all of your CAI off and run your truck. HMMMMM, doesn't effect nothing except your at risk of sucking **** into the intake so I do not advise doing this for any period of time or you'd cause harm to your motor. Yes you will not force air into your intake as you would with a CAI, but rather suck hot air from your engine compartment. The whole key here is cold air, and forced cold air.
So if you want to be a Naysayer, or just want to put a piece of verbiage out there so you sound important think twice. Sometimes I feel like some folks just need to be heard like a child. Simply put, unless you are a mechanic and can truly disprove something or feel that something may hurt another persons vehicle keep you lips shut.
I know of at least 50 people that have done this mod and love it. I am buying a 2014 Ram which will be in the end of this month. I will also install this mod again.
Oh so to prove my theory, please start the bashing back or blabbing...... Blaaahhhh, Blaaaahhhh, Blaaahhhh..

 

I don't even know if I updated my intake in this thread......it's been so long. here is the afe I'm sporting instead of the sh*tter pipe.

 

Just to support the 4 to 3 to 4 theory...it's called the venturi affect. I'm petty sure that's grade 10 physics.

 

Why would you use a 4 inch CAI when the throttle body cant handle that much air. Yes, I'm sure it sucks, but will do nothing for your performance, since the TB can only allow what air it's opening size is, so your on overkill, and have improved nothing. My guess is you had to use a reducer to connect that 4 inch CAI to the TB, so you should see that the 3 inch you had was the proper size

 

I know what you are trying accomplish, and even stated the venturi effect as proof of your thought. Now i could be wrong and maybe someone could better clarify things. Venturi effect states that the decrease in diameter of a tube reduces pressure and increases velocity. Your overall design is a 4 inch tube which at the filter end pulls from 3" to 4" and at TB end constricts from 4" to 3" the larger diameter throughout the intake does not create the venturi effect. I do agree if you had a 4 inch overall and constricted to 3" at the TB would create your desired effect. The smaller fitting at the filter end restricts the air-flow into the tube and thus cancels the desired effect. Like I said my thoughts could be incorrect and if they are i'm interested to know what others thoughts are as I am looking to build my own CAI.