Ok from the fcatory, where the y-pipe goes into the converter, is it just connected with a clamp or is it welded? My clamp is like gone and it just looks like its rusted on.

 

You mean whether the cat converter is welded on or clamped on ?

 

On my dual-cat car, one of my cats is stock (ask and I'll tell you how bad it gets): the 2 1/4" pipe goes straight into the front of the cat and is connected to the f-pipe by a bolt connection. The non-stock cat is welded in the front to the downpipe and is u-clamped at the rear to the f-pipe.

If you are replacing your stock cats (hopefully you are) then you can cut the pipe from the cat. I will be replacing both of my cats and may be using band-clamps front and rear.

BTW, anyone know where I can get 2.5" N10 downpipes? I've checked Summit, Edelbrock, Jeg's, Dynomax, Muflfex.....I'm thinking I'm gonna have to fab them from the Dynomax assortment of mandel pieces.

 

I think catco makes a N10 replacement dual cat setup that contains two high flow cats, and 2.5" piping conecting the cats to the manifolds.

 

Here's the link:



It's expensive



The part # is CTO-4153 I can't get the link above to work.

 

Holy crap, that's SOO close to what I need! I don't think I can thank you enough SGM. Hope I can be of some help to you someday.

THANK YOU..Eric

 

You make me feel special

No prob,

Campi

 

Geez, get a room!!

 

 

Ok ok, since it appears I have created a love-fest, I'll put a stop to it. I'm still gonna piece together a full 2 1/2 " setup. I was gonna try and do true dual, but a few factors killed that idea. So I'm gonna stick to my plan-b here w/ 2-2 1/2" from the headers out to the cats then out to a 3 1/2" Mufflex w/ spintech, out to 3" tailpipes.

Good times in the garage to come.......

 

I'm jealous. Nothing better than lying on your back welding and a hot molten piece of metal rolls under your back!! Ahhhhh....good times!! Good luck with the project.

 

Oh no..I am not going to weld, got no idea how to do that. Notice I said "piece together". I'm gonna let a pro weld it up for me after I'm done.

I did some more digging and found out that those 3 1/2" Mufflex's are only after the f-pipe behind the cats. I'm confused as to how effective that really is. I'm under the impression that the f-pipe isn't 3 1/2" around..maybe 3"? I dunno, I wouldn't think that going 2 1/2" thru cats, then out to 3" (or whatever), then out to 3 1/2" is kind of counterproductive. Please enlighten me.

 

When you say f-pipe what do you mean. Stock y pipe can be 2 1/2 or 3" into cat and either 2 1/2 or 3" for the intermediate pipe to the muffler.

 

I neglected to mention I have an N10 car. I am talking about the pipe AFTER the 2 cats that merge into 1 and then go into I-pipe. My thinking was that it seems to be the prevailing logic that the best flow would be achieved from a single pipe diameter all the way through as opposed to 3 different diameters, steadily incresing from the headers out to the muffs.

 

Not necassarily. If you look at a "stepped header" this type of exhaust works very well. What you really want to look at is the cost of going with the larger pieces and how much of a performance gain you will get by increasing the diameter as you work backwards. At the end of the day you will see minimal gains by going larger than 3" past the converter. You will see gains, just not earth shattering gains. So how much is it worth to you? Only you can decide that.

 

You're right about the cost vs. gain. I calculated all I was gonna have to do for the 3.5" cat-back set up and how much my true-dual would be if i DIY it. I was kind of surprised that the DIY true-dual will end up costing me less. So, back to plan-a.

I had never heard or read anything about the progressive pipe diameter. Glad I asked.

I also found a puncture in one of my cats yesterday. Another reason I can't wait to tear the exhuast out of this car. Pipes flattened. Bends flattened. Crinkle-bent pipes. 1 stock cat, an aftermarket cat 1/2 the size of the stocker. Welds that look like they were done in shop class. AIR system going to ONE HEADER....and that's all. I am happy w/ my exhaust sound, but form must indeed follow function. Yeah, we're goin true-dual!