dcsmith98

I have a 1998 Ford Mustang 4.6L V8 that I've had for a few monthseconds and I want to make some changes to the exhaust. However, I have no mufflers but I have multiple sets of catalytic converters as well as what looks like a set of resonators. I'm not sure what to remove from my exhaust system to keep it legal with one set ofor cats. Any help on what I should remove?

unitedwestang

Technically tampering in any way with the factory cats is illegal I believe. If you live somewhere where you must pass emissions, you may want to leave them be. If all that is required is a visual inspection you can take them all out and maybe put in some high flow cats. If you want REALLY loud, remove cats completely. Offroad or o/r midpipes do not have cats, hence why they are called offroad (meant for offroad use only). Some people chose to keep the factory mid pipe to just swap on before going in for an inspection. As far as mufflers go, pick whatever makes the sound you like. Watch youtube videos to hear what different setups sound like (there's a million of them).

dcsmith98

I am definitely taking all but one set of cats because I do only have a visual inspection I just need to know which set I need to keep. Or if it makes any difference. Like I said I have what LOOKS like 3-4 sets of cats and maybe a set of resonators. Not sure which is which.

unitedwestang

I've never had the stock exhaust on my car. I bought it with already modified exhaust, so I'm not entirely sure. I'm sure the first O2 sensor is probably in the manifolds, or shortly there after. That's really the only one that matters. They tell the computer how to modify air fuel ratio. The second set of O2 sensors just tell the computer if the cats are functioning. You can have them turned off in a tune without any negative side effects. With that said, how man cats are in between the two O2 sensors?