I took about 4 hours (total), polished and gasket matched the intake pipes, head and Y pipe of my srt and wanted to pass on the steps. This was easy work with a die grinder and air compressor without getting under the car. Basically I wanted to reduce the restrictions and improve the flow of air in the intake system. I will break the process it into different threads to provide more detail. Y pipe, Air Boxes, and Heads.

Photos attached:

Y is the view of the inlet "from the compressor" showing a 1/8" step, this was tapered and smoothed

Y3 shows the interior of the Y

Y5 and Y6 show the smoothed interior after using an abrasive drum.

The work is done in about 5 minutes after the y coupling is off the car. The TRICK here is to use a drum sanding roll and UNWRAP about two turns of the sandpaper so that the material flaps against the interior of the pipe. By unwraping the roll; the paper spins outward and rapidly smooths the interior while following the contour of the pipe. Wear safety glasses and dust mask.........

I used 80 grit to start and you can finish up with a smaller grit like 240/320 if you wish, this is to reduce friction and turbulance of the air flow. There is no reason to try to OPEN UP the passage as this the output of the compressor and there is plenty of cross section here, so don't over do it, just think "reduce restrictions and rough spots" to minimize turbulance.

Sanding rolls are cheap and available from companies like Summit and Harbor freight. An air grinder is faster but a drill will work also. If you use a carbide cutter as I did, the aluminum will clog it often, this can be removed rapidly by running the tool against a wire wheel to clear the 'teeth'.

Wash the Y before you reinstall it to clear all grit. When you remove the Y from the engine be sure to carefully remove the air sensor from the middle of the Y. The Y is connected to the car with three hose clamps tightened with a 9/32" or the metric size that is equivalent. I had the inlet airhoses removed to get the Y more easily. Iam also posting 2 more threads on cleaning up the inlet and heads which I also did in this 4 hours effort. Woody