I recently performed the following mod to my intake box and I feel it has made a noticeable difference so I figured I would share. As you all know the stock intake box that houses the filter has a lower chamber. If you pull the intake box up and out of the car the lower portion remains, bolted to the "framerail" of the car. Basically what I did was unbolt and remove this part from the car. Then I enlarged the existing hole in the bottom of the stock intake box (where the lower chamber I just removed attached to) to fit a 3" diameter pipe. I then attached a 3" diameter pipe to the bottom of the stock box. The pipe was a j-bend that I had leftover from when I turboed my sentra back in the day. I basically cut the "J" in the center of the radius at the bottom, this left me with a section of pipe about 14" long or so with a small 45 degree bend at the end. I attached the straight end into the bottom of the modified stock box. When I reinstalled the box with the attached pipe the bottom of the bend was pretty much centered in the space of the inner bumper area. I figured this way the stock airbox would be able to pull some colder air from the lower bumper area. Like I said the car seems to pull harder and it definitely sounds way louder with the 3" pipe feeding the airbox. I have the newer Takeda intake already that utilizes the stock box so that's why I performed this mod. This mod should make a difference for most people, especially those of you who use the Z-tube and flat panel filter setup, the intake sound will definitely be more noiticable. I will take it apart again to snap some pics if people are interested to see what I did.

Update with pics:
I used some adhesive heat shield tape to seal the small gaps I had at the pipe/box connection. Not required but the hole I made in the box was sloppy and I wanted it to seal a little better.

Here you can see where I penetrated the bottom of the stock box.

This is the view from inside the box. You can't see in the pic but there is a hose clamp at the top of the pipe that keeps it from falling out through the hole

This is a shot to illustrate how the pipe terminates in the fenderwell space.

 

i have a 350z intake airbox listed for sale, you can use this to mod like the stillen intake...

some pics be nice...

 

Sounds interesting, in for pics. I'd be a little concerned about taking in water. I wish I knew why they put those baffles on the airbox and the intake tube, is just for noise?

 

The intake isnt going to pull air from down there since it has two larger inlets closer to the filter. The only way this will make a difference is if you close off all the other openings and manage to "ram" the air in from that duct.

 

Maybe your car is different but the inlets on my stock box are not that big and that's why I did this, I felt the stock box was a bit restrictive. The surface area of the 3" diameter pipe is just as large if not bigger than any one of the other two inlets. Even though it would be nice air would never "ram" in from the bottom, at least the way I have it set up.

 

Post some pics up. I'd like to see it. I just finished putting in a cone filter in my stock box just for the hell of it

 

I did this last week and put in the rev up air box. Intake didnt get any louder although I did use smaller piping. I did put a scoupe (roof pipe flashing) in the bumper to ram air into the pipe. On the highway 80+ mph, she scoots.

 

Hmmm, I couldve sworn someone did something very similar to this a long time ago, perhaps as a DIY. Ill see if I can dig it up.

 

DIY cold air intake
https://g35driver.com/forums/engine-...-new-post.html

 

^ That was it, thanks.

 

Right on! Mine is very similar except the pipe I used is way bigger. Mine also does not make it all the way to the front of the car, it terminates in the fenderwell.

 

Someone did a DIY on something like this. I still have to try it. I don't see how it can hurt. Doesn't rain much in my area.

 

Updated with Pics!

 

I have been running this for about a week now with no ill affects. The throttle is snappier and it sounds great. I wish I would have dynoed this before and after.