Cat Converter

So since I will be replacing my muffler myself.. would it be a good idea to remove the cat converter or a bad one? Also any kind of gains, performance wise or even improved gas mileage by removing it?

Keep the existing one or install a new high flow variety.

Don't remove it, you could get a huge fine ($3000-$5000) and there is no performance difference.

but wouldnt switching the stock to a high flow create some type or performance gain provided it is allowing the high flow?

maybe, but it will be minimal.

wicked thanks man

So since I will be replacing my muffler myself.. would it be a good idea to remove the cat converter or a bad one? Also any kind of gains, performance wise or even improved gas mileage by removing it?

Blazer's right, keep the cat....These vehicles are designed to run with the cat in place....not to mention running afoul with the law.

What year is your truck? Some of the early GM "monolithic" cat converters are very restrictive. These converters have the beads in them and they are fairly large, boxy and have a plug in one side. A new replacement will flow much better. If you trucks got high mileage, a new cat will help...and they aren't that expensive anymore....check NAPA for a price

Cheap catback system: Go to your local muffler shops and see if and what they would charge to bend up a replacement stock system only using larger diameter pipe...say 2 1/2" ID... that will improve flow over the stock system. I would try the smaller shops as opposed to Midas. You'll pay a premium for the gaurantee (on the muffler only) and they may not be interested in "custom" work. The small shop may also let you bring your own muffler....something Midas ain't gonna let you do. If it's okay with the shop to use your own muff, lay hands on a nice, free flow muffler that will fit the pipe diameter...my favorite is the Dynomax Turbo muffler. Its been tested as being one of the highest flowing aftermarket mufflers. It won't rattle the neighbors windows but then it won't turn the cab of your truck into Dr Demento's Resonating Chamber of Doom either.

Good luck...

Mike

Yip, leave the cat on, chances are it is fine anyways.

I just recently replaced my cat. There were pieces of it in the muffler. If yours is bad, really bad, it will have disintegrated and there will be ceramic parts in the rear part of the exhaust system.

Was it rattling in there?

Was it rattling in there?
I have a 1998 Chev s-10 pick up and i just had to knock the ceramic out of my Cat. because it was cloged and before that there was a very loud rattle coming from there.

Illegal.

you also have to remember. obd 2 vehicles check for catalytic convertor efficiency with an o2 sensor behind the cat. if you hollow it out or add a performance (non-50state legal cat) your mil light will come on and your fuel efficiency/performance will be lost.

^^^what he said or you can insert a O2 sensor simulator.

hahaha, that works until its 50 state nation-wide (i don't know about Canada eh) law that your emissions are tested by a machine that connects to your tailpipe.

Not every state does the exhaust sniffer.

i am in tampa and there are no emmission laws. for now!

that's what I mean. Here in Michigan everyone scoffs at the thought of having their vehicle inspected, let alone the dea have their car sniffed. It's safe to say there are a ton of old junkers here that would NEVER pass a real inspection. But hey, it's the automotive capital of the world... right.

I'm from New York where every vehicle needs to be inspected once a year. The sniffer is supposed to come into NYS law very soon. They already have laws that you can't engine swap with an engine older than your car.