first time reader, first time poster...i've done research and havent really come up with a solid answer.....

so, as for my opener, i've read that there's two catalyst converters --- one in the exhaust manifold and the other downpipe of the manifold...now, if i remove the downpipe one, i've read that my baby wont pass exhaust tests. anyone know for a fact i wont/will? now, if i replace the downpipe cat with a higher flow (not test pipe) one, will i pass or have issues? also, if i get a new exhaust manifold (one without a cat....here i am assuming they all dont have cats or, atleast, all lancer exhaust manifolds dont have one), but i have stock cat, will i be ok?

to sum that up...
no exhaust manifold cat + stock/after-market downstream cat = pass?
exhaust manifold cat - stock/after-market downstream cat = pass?

also, off topic yes, but does anyone know how reliable this is .pdf is http://www.mivec.co.nz/tech/4G9x_Engine_Manual.pdf ? seems it, but i dont feel much like tearin into my engine and testing it...

so, back to topic, anyone know where i can get a cheap catback (ok, im not 100% sure if im usin catback properly...im assumin it means catalyst converter and back....haha, but for us lancer drivers, that means more then others, right?)? whether it be online or some place like autozone/pepboys/something like that...

i live in VA Beach, so if any other VAB locals know a local place or are willing to help in anyway, PM me, por favor...thanks for reading my novel, i'll be around to sign covers....

 

Taking away either one of the cats, will more then likly set a CEL and you wont pass emissions. Your car looks at your O2 sensors in the exhaust to see how well your car is burning up that fuel/air mixture, and without the cats, it will see that something is not "in-spec" within the PCMs range. They do make "CEL" eliminators for your O2s, which from what I gather is just a spacer for the O2, sometimes they work, and sometimes they dont. But if your state uses a pipe sniffer for emissions, you would more then likly most def. fail, we used pipe sniffers on OBD1 cars here in mass up until last year, and they're pretty brutal

 

no known bypasses? like, getting a better cat at the mid-car point and maybe getting a different O2 sensor and the header O2 (i've read there is one, i could be wrong and if i mean, feel free to tell me) get a different one or remove it or something that will not get the CEL goin? i probably sound like an idiot and that's fine...haha, just curious and wondering if anyone has thought about or tried this...i'd prefer to have one cat, not two and willing to be a mad scientist to accomplish this, not have CEL on and pass the test....

hmmm, so, if i get a new mid-car cat, i'll be fine...

 

Well, if I'm not mistaken, the 2nd O2 is a Cat Moniter, montiers how well your cat's are working, so it may not work

 

both sensors are located before each cat
sensor 1 takes a reading
sensor 2 takes a reading and compares it to the reading of #1
if the 2nd reading is lower, it's all good and no cel.

Now remove the first cat
sensor 1 takes a reading
sensor 2 takes a reading and compares to reading #1. Oh oh... both readings are not identical... boom... cel

To get around that... flip your second cat so the sensor reads after the second cat instead of before. The readings are going to be different meaning no cel. It's been tried before and it worked.

Doing so means you'll have to extend the second sensor wires because they were meant to be in front, not after the second cat.

As far as emission tests are concerned... there is only 1 way to find out. Try it out. If you don't pass just put your stock parts on and go at it again. It takes what? 30 minutes to swap a header/down pipe combo? To save you the trouble if you have to install stock parts, don't put the lower left nut on when you install the stockers. You'll save 10 minutes on the install time, and another 10 minutes when comes time to take it back out.

 

I'm running a turbo manifold and I'm catless, I just get a cel for the second cat being out, but I clear it with evoscan.

I'm in Newport News, do we even have emissions testing here?

 

hmm... im catless, but no CEL!

 

thanks all, for the help...i was thinking about if it would work to extend that second o2 sensor, so you answered before i asked, thanks, Blaze

Thunder, im not even sure, honestly...i've never had a vehicle long enough to need to go into the shop and get it checked, haha, my step-dad says we do...so as far as i know, we do

does anyone know if the road race motorsports' header has a cat in it? (http://www.roadracemotorsports.com/s...loads=0&page=1), seems like it doesnt...but wanna see if someone here knows for a fact...

 

After market header don't usually have a cat converter. The cat restricts the airflow and that's the main reason people go aftermarket.

If you wanted to save a few bucks, you could even hollow your stock header and see similar performance you'd see with an aftermarket header such as RRM. Someone in Toronto tried it and the difference between the hollowed stocker and RRM header was slim to none on the dyno.


Anytime mate. This place thaught me alot so I try to give back whenever I can

 

haha, one more question...what would be the best way to hollow it out? just shove the wooden handle of something down there or what? there an easier uninstall for the pesky cat? im assume mitsu didnt have a dirty reason for putting it in there, too....

 

really only if the cat is causing a restriction in the exhaust will you pick up power and i have my stock front cat in 120k and after that it goes to 2.5 borla and i did a exhaust back pressure test from the front o2 sensor port and i had 0 Hg of backpressure at idle and 0 Hg at 2500 so unless your cat's are bad which cause a restriction you really wont pick up any power from changing them. but that just my .02

 

I'm agreeing here. I just got rid of mine b/c I needed to change my exhaust up a bit when I did my turbo install and didn't have enough money at the time for a HFC.

 

Yeah they did.
It prevents pollution.

 

i know it helps to prevent it..but i mean one in the exhaust manifold...as far as i know, mitsu's the only one that does it...

 

Plenty of manufacturers do it.