Yep, here is "ANOTHER" stock airbox that has been modified with a cold air intake set-up.
The hole in the box is 3.5". The part attached to the box is a 4" Closet Flange (or toilet flange) with 3" PVC attached (cemented) to it. These parts are solid and will not come apart. I set it up so that the air is being picked up right about mid-way along the frame rail.
Total cost in parts was about $11.00 with the hardware.
I'm also running an aFe ProDry S, gutted baffle, and the turbo silencer "fell out".
Performance wise, little faster spool-up and maybe 1-2 mpg. But the sound... priceless!

 

Cool Sean. Great work and excellent pics. Sounds pretty good hugh?

 

That is the exact same toilet flange I used. I meant to put some flex tubing on it and direct it down to the ground like the PSM cold air intake does but I never got around to it.

I have the Diesel Power Products cool hose along with an Amsoil nanofiber drop in filter, but I haven't removed the silencer ring.

I didn't experience any change in mileage with these mods but did notice a lot more noise, but thats ok. Spool up to me was a little quicker.

I keep a detailed spreadsheet for my mileage using hand calculations and the only thing so far that has improved my mileage significantly enough that I could notice was the timing advancement provided by the Smarty.

 

That looks great. Been thinking about adding that to my intake set-up. Why didn't you put an elbow at the bottom to ram the air in? Would that make it better or would it be too much? Do you have any issues with water from puddles or flash floods?

 

Nothin' like plumbing fittings for the airbox mods! Cool! Hopefully nobody tries to take a dump in your airbox! jk

 

No issues, that's why it's not ram air.
Test: I cleaned off the inner fender well in the location where the "down tube" would end up. Then I drove up to the mountains while it was snowing. When I came back I checked to see how far up the water/road grime got on the inner well. That is where I ended the tube.

It makes a nice back up when you can't find the "facilities"!