A while ago I recieved some advice about a custom exhaust and while I have done a little more research I still have a few questions.

My plans, front to back are:
SR 4-2-1 Headers
Car Sound 2.25inch cat
48 inch perforated core resonator
2.25 inch pipe
magnaflow muffler

Q1. I know the first O2 sensor goes in the headers, and the second goes behind the cat - but where would I put it? Should I

a) get an OBD2 style cat so I can screw it right in.
cool.gif Put a hole in the resonator
c) ????

Q2. What is a perforated core resonator? Is it the same as a glass pack? How much should I expect to pay for one?

Q3. Which model muffler should I get. I'm going for a pretty quiet sound and I drive an 5 speed Elantra GT, so you cant really see the muffler. The stock muffler (shell) is 18 inches long, 7 inches tall and 10 inches wide. I assume getting a bigger muffler means it will be quieter. Is there any benefit to getting a single in and dual out muffler?

 

#1. the first o2 sensor should be as close as possible to the junction of the 2-1, but AFTER that junction. It would work to put it after the flex pipe, but right after the joint from the header to the flex pipe would be ideal. The second should go as close as possible to the cat, but AFTER the cat. (no more than 6" after). DO NOT install the o2 sensor in the cat, or in the angled sections after the cat. Only install it in straight pipe.

#2. There are 2 types of Resonators/glasspacks. Louvered core, and perforated.

Louvered core means there are u shape cuts in the inner metal tube and the flaps are bent up into the air flow. You can either install them so that the exhaust gasses flow Up the louver like a ramp (the right way) or install it so that the exhaust gas is forced to travel down the louver into the outter chamber (the wrong way to install one).

Perforated core means that there are holes drilled in the inner tubing. There is no right or wrong way to install a perforated core unit. The holes are NOT directional.

Some companies have recently started doing louvered core glasspack/resonators with the louvers bent away from the inner core into the fiberglass packing. These are better than normal louvered core, but still not as good as perforated core.

#3. I reccomend Magnaflow. Deep rich sound that is not loud. Muffer size does not always equate to noise level. Some small mufflers can be rather quiet...however, they tend to be restrictive. There is no real benefit to single in dual out other than appearance.

 

So the second O2 sensor needs to be installed in
-a small piece of straight pipe between the cat and the resonator, or
-can I put it IN the resonator, perhaps on the end that gets welded on?

How much should I expect to pay for a 48 inch perforated resonator?

 

That rules out resonator. You should put it BEFORE the resonator but AFTER the cat.

 

Are you doing this yourself?

Most muffler shops will know where the sensors need to go and put them accordingly. The one I went to was way informative and told me basically everything in this post.

Is Tsudo a brand of mufflers? That is what it is called, right? That is what I am looking at getting. A very deep, viper sound, no fart, but a little loud. So i'm going to toss a resonator in the middle so it isn't quite so loud.

 

Okay, nobody, and I mean nobody does mandrel bending in town. I've asked about ordering the mandrel bent pieces and having them welded together, but I've been told it's expensive.

So, if I can't get 2.25 inch mandrel bent tubing should I go with:

A. 2.5 inch crush bent tubing
B. 2.25 inch crush bent tubing
C. 2.25 inch flexible exhaust tubing

 

i believe with what i have read before, that you would want to go with the bigger pipe for crushed, that way it is closer to what you want. say you want 2.25, get the 2.5 cause when it is crushed itll be about the 2.25. it will be more what you want throughout the exhaust. if anyone needs to correct me go ahead, but that is what I remember.