I got a 99 lx and i want to add some 4-1 header. But there are only made for ex. I have order a high flow converter that an ex one. Has any one ever changed their catalyic conveter out for an ex one? what mod did you have to do?

 

Basically you have to get a cat for the EX.

The whole thing is you will be running an EX exhaust pretty much. However, relocating the Cat is illegal (in Cali and New Jersey that I know of) and 99.9% of the muffler shops out there won't mount your universal cat unless you already have the ex exhaust on the car.

 

I relocated my cat and passed the visual and emmisions inspection. I also live in NJ.

 

cat??? you don't need no stinking cat j/k

 

If you take it off yourself (the old one) they should give you no problems. What you do is this:

Buy header and exhaust for EX.
Buy either universal cat or direct fit cat for EX.
If universal, have muffler shop weld flanges on for you.
You might have to lengthen the O2 sensor wires so they fit. I know you can buy an extension for an EX that goes from the harness to the secondary O2 behind the cat. I think the primary plugs into most of the headers out there.

Done!