Does anyone know if this is possible with our cars without getting a sensor light on? I've seen it done on other cars and I actually had my cat removed on my 05 Ford freestyle with no problem at all. Just a thought that this would be a cheaper alternative to getting the less restricted high flow cats. Anyone done this?

 

How would you get around our annual state inspection?

High-flow cats are the only way to go that I'm aware of in Texas until these cats get to be 25 years old.

 

Honestly here in south Texas they never even check. Especially the independent shops. Even if they were to look at the undercarriage, there no way of telling if the cats have been hollowed out unless u have an emissions exhaust device. I know in California this would never fly but I'm in Texas; that why I'm asking to see if anyone has tried this.

 

A lot of the Mustang guys do stuff like this to trick the ECU into thinking that the catalytic converters are still in place and operational. In Arizona, they don't smog test cars that have OBDII.

O2 Simulator Mini Cat Cel Fix best oxygen sensor simulator made.

 

I could imagine that! Have been there once. Not as easy in most parts of North Texas.

I've looked into spark plug de-foulers to move the sensor out of the stream and not trigger the codes, but never got around to it (previous car). Although, it was a most amusing experience on the phone with AutoZone asking the guy if he carried them.

"De-flowerers??"

 

I think they would be able to hear that the exhaust had been modified somehow. If they don't care about exhaust modification in general, then that's great.

 

Problem with these are that they do not tell the ECU what is going on with the engine and if your car is running lean and ECU thinks the mixture right, you could burn a valve or worse ruin your engine.

If you put in pipes to replace cats, have a bung welded in for the O2's. Will only cost you about $8-9 per bung and like Fram says, you can pay me a little now or a lot later.

 

How many inspectors know the difference between factory OEM cats and something like the NP cats?

They shouldn't pass the visual inspection, at least here in CA, but the cats are pretty well buried in the engine compartment and do you really think the average smog technician would know the difference? Not likely.

 

Gonna ask my local muffler shop about this. Not sure of the same cat gasket can be re-used if Im just taking them off to hollow them out. When I first asked the owner of the muffler shop about modifiying the exhaust system he suggested the center muffler and rear muffler was the most restrictive. He also said he didnt like messing with things that have sensors like the dual O2s on the cats. Might be out of luck but it doesnt hurt asking...will update if its a go....

 

Huh? The exact opposite on all of this. And maybe it's a confusion due to state, though I can't see how Texas would be more restrict on smog inspections than The People's Republic of California. No inspector on average is going to spot the difference visually, if that's what mattered. I don't know about you guys, but in Texas, vehicles newer than 25 years old get their OBDII ports hooked up and the O2 sensors get scanned annually. A visually legit gutted cat is going to get illegitimate real quick once those sensors report their flow readings back to the inspector's computer screen.

How in the world do you get away with a visual in California? Has the corruption seeped into the local Jiffy Lube now as well?

 

Chris - I don't think everyone is up too par on this OBDII port scan via State sticker inspection. Atleast speaking for south Texas (I just got mine inspected 4 months ago) I have not seen this equipment. Its just the basic check the horn, lights, tires, brakes and take out for a test drive the last time I got mine. Considering the amount of mom and pop mechanic shops here in south Texas, I think Ill be safe for quite a while. Didnt know Texas was doing that already though - good to know. When I lived in Cali (over 16 years ago)- they had this smog device thing that checked your exhaust and it was over if you tired to sneak one by them....

 

Huh? Maybe you should re-read what I said.

I have NP cats and I live in California. Two different technicians had no idea what they were looking at. It's not like XKR's grow on trees here. How is a technician going to tell if the cats have been replaced or not? I guess if you're stupid and he asks and you admit to it....

Tell me how an OBDII port is gonna tell you if you're running factory cats or not?

 

Strange. Are OBDII scans not standard everywhere? Even in California? I find that shocking, as it's certainly strict at least just to that extent in North Texas. If all you get is a visual inspection, you can get away with all sorts of enhancements to the exhaust system. But if you're hooked up to an OBDII scanner without spark plug de-foulers (basically spacers) on the O2 sensors to move them out of the exhaust airstream, it will pick up more PPM or something out of spec than what is allowed to emit, and you'll fail the inspection with a hollowed-out cat (or poorly designed 'high flow' cat). But yeah, you certainly wouldn't admit that if you were engaging in such changes. I've run a nice high-flow cat before on a prior car and it inspected fine, and worked great (best of both worlds if OBDII scans are a part of your annual inspection).

Maybe it's time to start taking annual roadtrips to 'the valley' as we say for inspections...

 

OBDII scans at annual inspection time have been mandatory for many years here in the larger metropolitan areas of North Carolina where airborn pollution has a history of being a problem. Out in the wide-open rural counties where there are more white-tailed deer than people, I understand that OBDII scans may not have been introduced yet. But state law says that you must have your vehicles inspected in the same area where they are registered and taxed, so you cannot drive to the boonies for a quickie visual inspection in an effort to beat the system....

 

Again, how is an OBDII scan going to tell you that you're not running OEM cats? It can't. It doesn't know.

California has an emissions test that hooks up to the OBD port and a sensor that goes into the tailpipe. It tests cars at 15 and 25 mph and reads the emissions at both speeds. Either it will pass or fail. It won't say "hey technician, look at the cats, they've been changed".

 

Agree. Unless there is something really visually amiss like obvious aftermarket headers or pipes not hooked up, most technicians will not catch something relatively innocent on visual. Moreover, I do believe there are those shops that will "work with you" if you know what I mean. When I was considering some mods on the Corvette I used to own I asked the guy at the speed shop how the car would pass the 2-year emission inspection. He said not to worry--he could hook me up with a place that would pass the car. I never did the mods but this told me what I guess I already suspected.

Doug

 

My 97 Suburban has headers. They're CA legal, as far as I know. It was my understanding that headers are fine as long as they have all the smog stuff for that model year... mine only have O2 sensors, but it's passed smog and visual at several different places. Cats are a whole different story though...

The place I go to doesn't really do the visual check. I've been going there for 20+ years. But a new guy did do the visual last time, he hadn't a clue what he was looking at. And he was one of those paranoid techs worried about their license. All I cared about was passing emissions and I did. heh

 

ca. now separates cars to MY 2000 and older. older requires obd2 (if obd2 car)and sniffer test at 15 and 25mph on a dyno, 2000 and newer requires OBD2 scanner test . 1975 and older are exempt.

 

Man, the last time I suggested hollowing, or gutting my cats, I got "jumped on" by a couple of forum regulars for becoming the cause of air pollution across the Mid-West.

I'm still considering it, BTW. Though, I'd like to have input on the way it would sound. I'm concerned that it would sound raspy or tinny rather than throaty like most of us are looking for.

Anybody actually gutted their cats?

 

Where I live near Jacksonville Florida there is no inspection whatsoever, no emissions, no safety, nothing.