Hey guys just wondering what exhaust setups you prefer to use in this situation..

I picked up a 98 spec jdm 4-1 header w/ 2.5 outlet. I plan to use the stock usdm 00 exhaust as i prefer a nice quiet ride. any suggestions on the cat? I plan to retain the usdm odb2 ecu so i can't do a test pipe or the jdm cat. I know I can take to an exhaust shop and have something fabbed..

Thanks for the help!

 

Just curious as to why you cant retain the ecu if you opt for a test pipe?

The jdm exhaust and headers might be a bit different in length. You might have to mock it up and measure to see what you got.

 

from the research i've done, the usdm 421 exhaust manifold is shorter than the jdm 4-1.

the usdm cat has an 02 sensor in the cat..i'm not sure if it would freak out the ecu having the o2 sensor in a test pipe..never tried it before, i've only run a test pipe on a jdm ecu that didn't look for the cat 02 sensor. although i would prefer a test pipe it does't have to pass smog, just for no CELs.

 

Yea thats what I have read before.

Ok I see. I have a jdm itr and I installed a test pipe. I just clipped the wire to the sensor in the cat and have had no problems other than the red light for tthat sensor on the cluster.

Research some more on this sensor in a usdm as jdm may definitely be different.

 

To answer the initial question, I used a carsound cat. Don't use one, they suck *** - badly. Might has since fallen apart so it's really an inefficient test pipe at this point in time.

test pipe on OBD2 = CEL, however there are ways around it (temporarily).

O2 Simulators, you will occasionally get CELs, my 97 came with one installed, has a CEL for cat system efficiency.

You can plug the bung in the test pipe, wrap the O2 in tinfoil and pull it into the cabin and cover the hole left behind. Same result as the O2 Sim, you will occasionally get CELs, but it's free basically if your test pipe comes with the bolt, otherwise you can get them locally.

Or, you can ignore the CEL (Cat system efficiency code does nothing besides turn on the light), or take the bulb out (which is what I do, I put the bulb back in to check codes every once in awhile).

 

any alternatives to a carsound (magnaflow) cat? I don't want CELs so a test pipe is pretty much out of the question.

 

JDM cat, maybe the renault cat that hytech sells (you'd probably have to get flanges welded on it).

Personally I'd live with the CEL, it's meaningless in this case.