N-Tech High-Flow Catalytic Converter

This product replaces the main catalytic converter on the car. I have not installed it yet, but I wanted to share the pictures and some other information about this part. It is almost entirely stainless steel, I think only the heat shield is not stainless. I was pleasantly surprised with the high quality and attention to detail in the flanges and welds. I was not expecting such careful construction at this price. It weighs 11.6 pounds, which is undoubtedly a good bit lighter than the stock piece. It comes with what appears to be stainless steel bolts, nuts, and lock washers for all the connections.

I added two stock gaskets (purchased from Mazdatrix, but also available at the dealer), which have only a 2.75" inner diameter, where 2.825" would be perfect. At first I was little alarmed at the sizing, thinking that I was going to hurt flow with some stupid gaskets, but then I realized that it doesn't really stick in that far and I was not going to find any higher quality gaskets. And I had heard that the stock main cat has a 2.2" section at the inlet and outlet, so it seems clear the decrease in flow resistance will be significant, even with the slightly undersized gaskets.

I also got a piece of high-temperature silicone hose from Baker Precision to hook up the air pipe. As you can see below, the N-Tech cat has a port for that connection, but comes with a plug screwed into place. I plan to cut the flange off the stock cat, and use the silicone hose secured with hose clamps to make the connection. I got some 5/8" hose, but I think that might be too big. I will have to try it out and see. 1/2" hose might be a better fit.

Updates July 27, 2001:

Don't bother trying the silicone hose. It did not last long, so I ended up having a shop weld the connection for $25. It didn't cost much and has held up well.

I thought I had clogged the cat due to running really rich and running synthetic oil, but the cat looks great. I had low boost, so I installed a mid-pipe to see if that would fit things (it didn't). The brick inside the car looked brand new.

I just barely failed my California emissions test with a downpipe, mild street port, and this cat. I reinstalled the pre-cat and it passed with no problem. I bet a car with stock porting would pass with a downpipe.

Here are a bunch of pictures, I apologize for the focus and I hope see everything you wanted to.

cat_hardware.jpg (12448 bytes)