2002 + SE-R Spec V after market Exhaust manifold & O2 Sensor

[Soravia]

Has anyone used an aftermarket exhaust manifold for SE-R Spec V that has no issue with the O2 sensor? I don't want to do the custom works on a manifold and risk messing up. I'm thinking OBX 4-2-1 but not really sure if I can just plug the O2 sensor in and make it work.

I could just drive with the check engine light on but then I won't know if the engine has any other issues. So no go with that.

Thanks

[nametakennow]

Run a search for this. There have been a multitude of discussions on how to avoid an SES/CEL (you're lucky, FL doesn't do emissions testing, though that wouldn't matter either).

The short answer is that any header will work. Plug the first O2 into the manifold and either move the second one back behind the main cat or use a spark plug defouler to make it read clean.

[Soravia]

I've noticed that my car already had the CAT removed by previous owner and it has aftermarket muffler and two resonators. There are no CEL light.Does that mean I don't have to mess with the O2 sensor anymore?It still has the stock Precat and I'm trying to eliminate it along with fixing the butterfly screws. Will removing the butterflies lower my lown end torque?

[Soravia]

Any of those Defouler, O2 Eliminator, etc on the 2nd O2 sensor affect the Air fuel ratio?

[nametakennow]

The main cat has no bearing on the CEL.

You'll need to do the defouler method to avoid a CEL.

The first O2 sensor is what is used for a/f management and it will continue to get the same reading, so you won't have any problems.