I haven't looked but I was told I have 4 cats. Do I need all 4 cats to pass inspection or would 2 be sufficent to pass. I would go look but I'm on the mustang and at the muffler shop so I can make plans to take them off.

 

if you remove all 4 stockers you need to add 2 highflows...

 

I will tell you what I learned after getting a 'smog' inspection here in Maricopa County, AZ, and asking questions of the smog examiner.

According to him, as long as the catalytic converters used to replace all 4 catalytic converters is sold as a 'direct replacement', you are fine (for example, 2 Magnaflow 94106's for all 4 OEM cats), and the O2 sensor is in about the stock location. ONLY after I asked this question did he look under the hood to confirm what was done. When he saw what was done, and how it looked nearly stock, he was happy.

This guy was super cool about the testing procedures and answering questions, and also seemed to know the laws in this county very well.

Check what your local laws are. Some areas, like California, are VERY particular about what you do with regards to 'tampering with smog control devices'.

 

Here some are asses some are cool. But at the shop I was at he said it should be ok. I have two bbk high flows that I was going to use.

 

You can replace the 4 OEMs with 2 hi-flows, but check with your localstation to find out.

 

AZ, what kind of testing procedures did they perform on your truck? We have the OBDII here I think, and I am looking at doing 2 hiflows in place of all 4 cats.

 

OBDII is emissions testing

 

I knew that...but I was wondering if thats what he passed or if it was visual or the tailpipe test.

 

jpf150,

A simple OBDII test. All they really did at the start was to plug in a fancy code reader to see if there were any current or pending DTC codes. Also checked to see if the O2 sensors were on and functioning. After asking about the catalytic converters, then he did look under the hood. It was more of a glance than an inspection, mainly to satisfy his boss. Otherwise, rather painless procedure, no need for a first aid kit, vaseline, or EMT's.

Like someone else previously posted, depends on the person doing the test. The one I got was an older guy (45 to 50 ish), who was an old hot rodder like myself. He was super cool about it, as he said, "I really could care less about what is under the hood, as long as it looks stockish to me".

 

Alright, thanks! Thats exactly what I wanted to hear.

 

Me too! I'm getting them switched asap. Unless the dynomax bullets make it too loud with all 4. Then I'll just keepem

 

Replacing the cats with BBK high flows off my mustangs old x pipe right now. Will post later on any changes.

 

After an hour and a half wait I left... way to busy. Ill wait til I get headers and do it all at the same time.

 

See you have an 04 not sure what body style yours is...

My 06 I crawled under and only have 2 cats...

Manifolds, to cats, to exhaust pipe, to muffler then out...

Which style trucks actually have 4 cats?

 

^ I think it is a matter of when it was built, not what model it is.