If you ever wanted a test pipe without the CEL on you OBD II car look here!
Get a test pipe with out an O2 bunge. Take your O2 sensor and wrap it with tin foil. Then wrap it with electrical tape. Zip tie the O2 onto the sway bar.

The tin foil fools the O2! Amazing but it works.

 

sweettttttt

 

u sure it doesnt fool with anything else?

 

hmmm yeah okay many people know about this already, but I myself prefer not having to "jerry rig" stuff like that, nor do I like screwing w/ the environment. I would suggest a Carsound cat which should have places for both O2 sensors if you get it for OBD2 cars. It will flow nearly as much as your test pipe and be alot cleaner and alot quieter, too.

 

Carsounds tend to throw a CEL 67 with OBD2 ver 2s. I guess the newer ecu programs are more strict.

 

I have a Carsound cat also and no cel. But the test pipe isn't loud at all, probably because of my RSR exhaust But the test pipe make more hp in midrange