<center><img src="http://pictureposter.audiworld.com/711/airin1.jpg"></center><p>with a Dremel, hacsaw blade, half-round file, rat tail file and some sandpaper.

In preparation for the Stage 3 cold intake I have to get the stock airbox flowing absolutely as much air as is possible so that when I supplement with the lower cold air intake I can keep as much of it's diameter as possible opened up to match the upper intake tract.

Just flowed this modification on the bench and picked up 4% more CFM@10" water. The flow dial registered 280 CFM on the stock airbox then 291.2 CFM with this mod and nothing else. Not a bad gain for an hours work.

Fist pic is of stock intake male flange area that cold air supply elbow slips over. You can see from the pic that all the leading edges of the stock airbox male fitting are thick, flat and with a large center reinforcement running thru the center and down into the airbox. Do NOT grind away this center reinforcement entirely as the flange will collapse over time due to heat and warpage. I left 1/2" at the thinnest area.

<center><img src="http://pictureposter.audiworld.com/711/airin2.jpg"></center><p>All straight edges were were tapered to a knife-edge with the various tools mentioned earlier. Most of the center rib was eliminated and ground into a contour on the bottom. The remaining rib is then ground to a knife-edge on it's leading edge (top) and radiused in the under side. Note: only inside edges are tapered except on center reinforcement wedge where both sides are done. Outside circumference is not touched as that would be counter-productive.

All sharp edges leading into the airbox are radiused and smoothed to allow less turbulence and easier transition into the main section of the airbox with no "steps" to encounter/overcome in it's path.

After everything is ground smooth it's then lightly dressd with a file then sanded to contour all it's ground leading/trailing edges to eliminate "threading" of plastic (little slivers of plastic hairs that want to remain).

This pic is of finished inlet ready to have hose re-attached.

<center><img src="http://pictureposter.audiworld.com/711/airin3.jpg"></center><p>Just another shot of finished inlet.

Nex I move forward to the CAI diffuser. I'll experiment with this in the CAI assembly, out of the assembly, modified with radiused inlet tapers and bored completely out if flow bench shows benefit. If that turns out to be the case I'll likely chamfer it's leading edges and remove all the diffuser vanes and just use it as a coupler for the intake duct-to-intermediate pipe as it's too weird a configuration to make easily or cheaply out of another material. But first I have to go mail a boatload of Stage 3 stuff at the post office &amp; UPS.

I'll post later on diffuser experiments.