I have some questions and need some advice/direction. I have a custom 2.5" exhaust on my EK with the stock header/cat up front. I was thinking I would relocate the cat to under the car like the B-series engines (I have a D16Y7 but did the mini me swap) and have been dragging my feet on the header because I want to eventually go turbo (thus the 2.5"). I don't believe they make a D series header w/ a 2.5" collector so I will have to get what I can for max size.

Now for the questions.

should I go to a cat (magnaflow 2.5" in/out) or a test pipe?

Can I still maintain the two O2 sensors?

Will I throw any codes with either one of these?

Which will yield the best power?

Would any one of these increase the loudness?

Also, I'm still confused about backpressure and all that if it's good or bad.

Summary, header-->2.5" Cat--->2.5" pipping to an exhaust
or
Header-->test pipe--->2.5" pipping to an exhaust.


Any info would be greatly appreciated.

Thanks in advance.

 

run a cat

what would be the sense in running 2 O2s if they won't read anything different?

no cat would throw a code

no cat will yield a hair more power with the cost being more noise and more pollution (IMO not worth it on a street car)

backpressure is a myth, look up pulse tuning

did you google anything?

these are seriously noob questions 101

 

I appreciate you comments. In response to your answers/questions:

1)My car is OBD2 so I they have one O2 sensor prior on the exhaust manifold/cat (one piece on the Y7) and one after the cat. I can't afford to throw a code so I want to put back what I originally have. I need the two because they check before and after to make sure the cat is running alright. I don't know if all aftermarket Cats (magnaflow/carsound) have an O2 port or not. I found some pics showing the bung hole and some don't and I want to make sure I get the right one (if there is such a thing as one without).

2)I definitely don't want to add noise and I heard (famous hear say) that even with messed up cat's or no cats, honda's produce next to nothing for emissions/smog tests.

3)I never heard of pulse tuning, I will have to check that out.

4) Yes, I always google before I post but this car/setup is specific and I want to make sure it's apples to apples.

5)Noob questions or not, I would rather hear feedback/comments then go out and spend a few hundred and regret it. No offense taken or meant to be given.

 

i remove da cat on my moms car no extra noiseor codes runs a bit faster, but on my gf integra the size of the pipe is what made the extra noise and power, too big not good, what do u want like stock or some power, cause would go with some new headers no cat and still keep the two 02 sensors, i mechanic told me the second is there 2 check if the 1st is workig properly and if not to take over its role till it is fix mind u i was told this dont know if tru or not