For all the exhaust experts.
 

I had a huge exhaust leak in the flange that connects the pipe going to the muffler and the cat converter. Apparently the gasket was half gone and the threads were actually in 2 pieces on 1 side. I tried to take it off and the nut broke off the threads on both sides and instead of spending the time to try and tap them and deal with all that headache, I just cut off the flange and most of the cat converter so there is just pipe to connect to a new pipe. I am wondering a few things though.

Question 1: I am wondering what this little pipe connects to in this picture. It goes to the cat converter held in by 2 10mm nuts and goes up into the engine bay.
http://i114.photobucket.com/albums/n...2011210530.jpg
Also I am wondering what this does and what to do with it now that the cat will be off of it. Weather I need to plug the hole with jb weld, or take it off somehow, or I have to reattach it in some way, or just leave it dangling there.

Question 2: I see everyone upgrading the headers but when I looked under the car I am used to seeing the cat converter attached to the headers, and all I see is this big ass box that connects to the carburetor. Now this isn't really needed for anything I am doing right now but in the future I plan to get headers for this car. I am just wondering how you go about replacing them and where they are really at? Are they inside this box looking thing and you have to take that off to get to it or what? lol

Question 3: Anyone know around about what degree bend I will need to fit a new pipe on this car? I pretty much need to know the degree bend that the pipe is originally but I am guessing maybe it is around a 45 degree bend.

Also Is a new heat shield necessary? The one that is on it is completely destroyed. It has more holes in it than swiss cheese.

Kinda hard to tell due to the pic being dark but if I had to guess id say the pipe runs to the airpump?

That pipe you are referring to in the picture is an air pipe. Comes off of the airpump and runs to the cat. It injects fresh air into the cat for a more complete burn. You can just follow it up into the engine bay, it should connect to a rubber hose. Follow the rubber hose to the engine side, loosen the hose clamp, pull off the pipe and rubber hose and throw it away. Don't need to do anything else.

Ah it will not cause any vacuum leak or cause the car to run badly with it not on there would it? Would I need to plug anything up or just take it off?

Nope, won't cause any vacuum leaks. You can just take it off, it'll just continue to pump air. No need to block it off or anything.

I assume you don't have any emissions testing where you live. If that's the case you might as well take the time to strip it all off. There is a well done tutorial here: http://maz_tutorials.ten15.net/ . Download it, read it 10 times, then bring your laptop outside with you and get to work. Makes the bay much easier to work in and much prettier to look at..... well except for DivinDrivers bay.

Unless you're removing or gutting the cat, keep the air line from the air pump connected and operable. W/O the air pump feeding fresh air to the cat, the cat will die quicker.

Yeah I am removing the cat and there are no emissions here. The reason for this is the flange that connects from the cat to the pipe connecting the muffler had only half a gasket left and threads on 1 side was in 2 pieces. I tried to take it off and just snapped the threads. So instead of tapping it I figured I will just cut it out and the cat out and attach the few inches of pipe after the cat together to the rest of the exhaust pipe. I was wondering if this car will be possibly louder than it was before with the cat removed but with no leak, until I realized the cat was hollowed out already lol. But now I know that it is still safe to have this air pump unhooked, thanks everyone.

I am surprised at this thing. After a few hours and trips to orilley I finally got a pipe to fit on there. And without the cat the car still sounds pretty quiet and there is no more weed wacker sound coming from it. It is just loud enough to where you can hear it but not so loud that it sounds like a ricer... I do have to say these rotaries have a pretty nice note having stock headers and only some type of 3a racing muffler.. No idea what model 3a but it isn't the tube types, more like a normal muffler with 2 tips coming out of it.

That stock "header" is a large thick, cast iron maniofold and its the reason a lot
of the noise is being muffled. If you went to a real header that muffler wouldn't
cut it at all.

Oh that makes a lot of sense, thanks. I do plan to eventually replace that with the racingbeat header. I always thought maybe that was just some kind of container with the header inside of it. But also wouldnt the big hole on the top of that thing that has a pipe that connects to the air cleaner assembly cause an exhaust leak or something? What is to prevent that from causing a leak?

That is just a casing around the top of the manifold to capture hot air to feed into
the intake for cold start conditions. Under that is the exhaust manifold.

Ah so if my car is having enough trouble trying to start with it being 60 degrees outside then it is probably best to keep it on there lol.

I am running a Universal RB Exhaust on 2 1/2 inch piping. Like yours my car didn't sound loud at all. I eliminated the ratsnest and utilized block off plates. I used the tutorial orion posted and recommend completing it. Simplified everything!