What does it do whats its purpose can i go with out it? does it give more power.

Catalytic converter....considered "emissions crap"
What it is "supposed" to do, is block harmful chemicals from the exhaust getting into the atmosphere...
Will it give more power...eh......no....
The only reason I can think of taking off the catalytic converter is if you wanted to add a flamethrower system, you have to take off the catalytic converter for one of them....

TOC Admin
Brando

the only reason to leave it in is if you have to pass an emissions test.... you would have a less restrictive exhaust if you ran without one, but you probably won't pass inspection. I don't run one in my olds, but my car didn't even come with one, and I don't have to pass emissions because it's over a certain age.

In my truck I have a Magnaflow Hi-Flow cat.... keeps the exhaust more open, while still gettng you to pass inspection. Works pretty good. If you have to replace your cat. converter for whatever reason I'd go with one of those. But they're not cheap, so I wouldn't recomend doing it unless your old one is junk.

Its also illegal to remove a Cat (shorten version of catalytic converter) on emission control vehicles. I luckly don't have one my 442. They make the exhaust more resticive thus taking away power.

They are majorly restrictive, and as they age it gets more blocked up. (its like a honey bee's nest inside) On an olddd car with an original cat, a new one would make a noticeable difference. Taking it off completely, is yes illegal but it will make a really notice able difference, if not noticeable, the 1/4 will prove it. My car is 19 years old, i passed emissions in January with flying colors!! it came out better than my dads 98 Astro Van, Now its considered a "classic" so i dont have to test it anymore, off comes the original cat this summer

The catalytic converter gets a bad rap because of the early style pellet units. The modern OEM and aftermarket converters are not restrictive. I had a high flow converter on my '87 and there was no difference in the ET between no converter and having the high flow on there.
If you know your converter is junk then I would replace it with an aftermarket high flow model. If not then I would just leave it alone.

There were also dyno test done showing the difference between straight open pipes with mufflers and straight open pipes with mufflers and converters. The car (a Mustang) made around 10-15 more hp without a converter but it lost 10-15ft/lbs of torque without one. To me thats not enough to get rid of a converter.

Hey BigBlockOlds what kind of cat do you have on your olds, how much was it, and did it fit right up, or did u have to do some custom work?

I think it was a Flowtech with 3" in and out. The exhaust shop just welded a ball flange on the back to mate up with the Y-pipe and at the front they just clamped it to the stock down pipe.
Back when I bought the converter (mine was shot) I had priced a factory replacement style from Midas and they wanted $350 for the converter and labor to install it. I just went to the local speed shop and ordered a high flow 3-way converter for around $160.

I hear some of the best converter's out there are made by Random technologies. I'm not currently running converters on my car now and thats really only due to the cost since I have dual pipes. It will cost me around $300 to put them on. But I do plan on it because it will help quiet the exhaust down some more.