I Had the hi temp black header and downpipe. Yes the first cat is in the stock exhaust manifold and is taken out by putting on the header. The mil is attached to the 2nd o2 sensor and the first 02 sensor goes right into the new header. The mil will clear any fault codes and you should pass without any issues. You can still get the rrm header and it has a nice polished finish even if you don't go turboed

 

or you can turn your cat around...to be rid of CEL without the MIL eliminator

 

?????What you mean...turn your cat around??????

 

turn the cat aorund so the the o2 sensor is after the cat and not before it, and that should take care of CEL.

this has to do with our cars having 2 cats..like stated above....the first cat will clean it so the 2nd o2 sensor is supposed to sense it clean, but if you put a new header in then it gets rid of the first cat and instead ot the 2nd o2 sensor reading clean air is now reading dirty air, so if you turn your cat aound so that that the O2 sensor is after the cat, then it again will read clean air and get rid of CEL

 

Have you done that before? If you have how would I do it?

 

no i didnt do it to my lancer...but im pretty sure a few guys have on here, tho they may no longer be members...to do it you just have to turn the cat around, maybe lift the passenger side carpet to free up some wiring but ya...ill do it when i get my header again

 

So the O2 would come after the header than? Because right now the O2 sensor is before the cat in the header?

 

I have the RRM header and got a CEL light. I had to register my car last week and couldn't pass, so I had to reinstall my stock header, pass the emissions test, then I reinstalled teh RRm header again. I've got it down to only taking me 45 minutes In order to avoid the CEL, all the good suggestions have been made. You can add a MIL eliminator to the O2 sensor, you can switch around your second cat so the o2 sensor is after the cat instead of in front of it. I've heard there is a resistor you can add to the second o2 sensor as well which will get rid of the CEL as well. I'm looking into the third option. One other thing, after I put my header on, I needed to add a MagnaPack resonator to my exhaust to quiet it down. It makes your exhaust way louder and deafening at freeway speeds but after the resonator, it sounds great again.

 

Either one I do....mil eliminator or switching the O2 sensor after the first car will turn OFF the CEL. So then either one I do, I WILL pass inspection then?

 

Hrm.. I was always wanting to buy a header but wasn't sure which one to get. After reading this thread I am gonna go with the RRM. I already have the RRM test pipe, injen intake, and magnaflow exhaust. I am gonna choose the RRM because it doesn't replace the downpipe. Hopefully that will give me a little bit more low end power than the ones that come with the downpipe since the stock one is more restrictive. If needed, then later I'll go buy the Buschur downpipe. My car is kinda loud as it is, but by not opening up that stock downpipe and leaving it alone, it should be a little quieter than getting a larger diameter downpipe.

 

we have 2 cats and 2 o2 sensors

1 o2 sensor is before the first cat in stock header, and the second o2 is right before the 2nd cat.

when stock: the 1st o2 will read diry air and the 2nd will read clean air...

after a header install, 1st cat is eliminated and now both o2's are reading dirty air.
if you turn your 2nt cat around(the only one you can turn around) so that the 2nd o2 is after the 2nd cat instead of the 1st, then your 1st o2 will again be reading dirty, and since your 2nd o2 is not after the cat which cleans the air, it will now read clean air therefor getting rid of CEL

 

now the only way you will pass emission is if your car has been running and has been warmed up...but in most states you will not pass the visual part if you have one...since they will see you have a header

 

^^ Except in Utah - I passed the visual test, just not the OBDII test since I didn't have the sensors switched yet, so I had to reinstall stock header.

 

Thats why buying the MIL, which is not a lot of $$, and you don't have to worry about switching the cat around or putting the stock manifold back on. Then having to go back and put the header back on again. Do you really want to have to do that everytime you need to get your car tested?

 

I see. Makes sense.

Do you have a how-to on this? I searched but could not find. Thanks

Also...it's a direct turn around?...By turning the cat around so the 2nd O2 sensor is after the cat it fits right into place right?