Hello everyone just got a question as always, i recently got my 03 civic ex going and went to smog it, it fail the visual test for the cat not having any numbers on it, but the dude was cool and pass the vehicle. I know the 7th Gen civics have a garbage exhaust the only good thing is the header, when i remove the header i notice the there is no inner lining in the down pipe so its not the honda piping, also i didnt mesure but it looks like its a 2.5 inch opening and goes all the way to the cat and out the back to were i can see the pipe is smaller to the muffler. I will be taking it to find any markings on it but would like to know if anyone here has one.

 

Inner lining? The factory downpipe doesn't have an inner lining. If you're referring to the heatshields attached to various spots on the outside, that's possible.

 

It is well known that all 7th gen civics have a super restrictive exhaust, because of the 'padded bra' the 2.25 in. exhaust goes to 1.7 in., I don't know who called it that but ive gone to pick and pull and seen the the inner lining, my current down pipe doesnt have it so that is why i ask.

 

I have no idea what you're referring to with the terminology "padded bra", but there's no inner lining to a stock catalytic converter/downpipe. At the flanges, you may see the piping due to the fact that the flanges are welded around them, but there definitely is only one layer of metal to that tubing.

The removal procedure here: showcases what a factory downpipe/catalytic converter should look like (with minor exception to the fact that the factory heat shield around the converter itself has rusted off its hardware). Here's the part number for the downpipe/catalytic converter assembly: 18160-PLR-A00

If your car has something different then what is being removed in this video, then you have an aftermarket component. Honestly, though... the aftermarket options can sometimes last a lot longer then the factory catalytic converter on the D17's.


Just for future reference, there's really not a performance gain from replacing the stock exhaust components with "high-flow" alternatives... so its not really as restricted as you may think. The biggest numbers I've ever seen replacing the exhaust, intake, and running a tune... has been less than 10whp, which is entirely negligible (especially if you consider the cost).

 

Yeah im just talking out my butt cheeks about the Patted bra, thats what the 7gen guys call it, but its true these are doubled wall, the downpipe only not the cat, although it does double again after the cat.Ill get some pics later in if you or anyone cares lol, also i think your too generous with the 10hp gains, also im not too concerned about the cat, it works fine and looks pretty new plus ive already pass my emission test, but as stated it fail the visual and here in cali thats automatically disqualified, and green peace comes and hits me with a penguin, like i said im just curious if what i got is a High flow or not, guess only way to tell is actually going down there, if it is yay if not what Chinese junk do i have?, love the video ty, ive pass it several times lol

 

There are several options out there for aftermarket catalytic converters. If the shape doesn't emulate the rusty one in the foreground of that video still, then its definitely aftermarket. It'd be hard to tell what brand if there wasn't a label of some sorts. The only "performance" brand I've seen that makes a bolt-on option for the D17A2, is Magnaflow.

 

thats what im hoping lol.

 

well after a good inspection i can confirm several thing, i now have a true 2.5 inch exhaust system,dc header, although i think the stock one was better and a 2.25 magnaflow street muffler, my cat has no numbers except for some faded marker numbers, and that it looks like it was fab up nicely, looks like the real deal and i think its hollow so yeah.