Catalytic Converter and Horse Power. Why more HP? Part 1

When I replaced my catalytic converter it had to be cut out. The new one has to be welded back in. Facing all that work, I didn't even consider cleaning it as seen on Ericthecarguy's channel in this video catalytic converter cleaning. I've seen a lot of Honda's on Ericthecarguy's show and one Honda on an AutoZone show easier to remove catalytic converters with flanges. Theoretically, You can just bolt the new one one. Catalytic converters last too long and exhaust rusts, so "easy" is not how it usually still turns out. How kind of Honda to help make this possible. (Forgive me if I forget that maybe Eric had to add the bolt in flange to make that true?)

Anyway. I bought my catalytic converter (often called a cat) from Auto Parts Warehouse. First and only product I've bought from them, being fans of AutoZone and O'Reilly. I got it for $98. The reason I bought it here was because when I talked to O'Reilly's or AutoZone they wouldn't look at their database without my car in it. So, all they would see is stock cats. Only Auto Parts Warehouse out of 5 stores would work with me to look at cats by their diameter of pipe. I bought an Eastern Cat made for GM cars, which were designed to resist coolant and oil better than other cats since these leaks burned up so many cats on GM cars. It was legal in all but CA and I think NY. Catalytic converters don't have to always be expensive. If you live in CA or NY this article really doesn't apply to you (be sure to check your local laws). Since I thought I had a 2.5" catback upgrade I went with a 2.5" catalytic converter. I wanted a little more power. I went from 59 to 90.1 wHP. Not a little more!

It turns that my catback upgrade of 2.25" exhaust measures 2.5" on the outside, whoops. So, that was also a lot of extra work, but I wouldn't have done it any other way as this reduced back pressure further. Since catalytic converters are the biggest bottleneck on the exhaust getting out of the tailpipe, I figured bigger was better. I had to use pipe conversions from the catalytic converter to the down stream pipe. Plus, the 2.5" OD catalytic converter needed a 2.5" pipe into it, before the pipe converter would work. The converter and the catalytic converter were both 2.5" OD, meaning it fit over 2.5" and was more like 2.75". ID means it'd fit in rather than over. If ID and OD aren't mentioned it SHOULD be actual 2.5", not the case for the catalytic converter.

The worst part of the conversion was going from the 2.5" OD pipe of the catalytic converter to the 1.75" stock down pipe. They don't make a conversion pipe do that all at once. Took 2 conversion pipes and hours of cold steel work with a pipe expander that broke on a 2" pipe to get big enough to fit over rather than under the 1.75" down pipe. (The pipes I bought were 1/8" thick which adds to 1/4" of size for how it fits, but the stock pipe's were much thicker, maybe .375" thick.)

Back to back pressure on part 2 of Catalytic Converters and Horse Power.

by AutoBravado