Dude, are you SERIOUS?? I specifically SAID multiple times that I am NOT against catalytic converters, and never tried to prevent anyone from putting a cat-back on his car (now who's making things up??).
That's nice that you've "been here" but I have lived here for a half a century. I guarantee you didn't bring an air quality sniffer with you. What you were "seeing" was DUST. It is very dusty here. You cannot see carbon monoxide, hydrocarbons, or oxides of nitrogen. It is a FACT that we are in the TOP TEN in the U.S. for clean air. That is not some statistic I made up.
You could easily look it up yourself. It's funny that guys here want to split hairs & nitpick that we're not number one or two (or number 8, apparently), as if they really "got me" making a erroneous claim.
They ABSOLUTELY discontinued emissions testing here in 2006 or '07 because the air is CLEAN and therefore it's an unnecessary expense and annoyance for car owners. It wasn't for any other reason. It wasn't out of the kindness of their hearts. Other parts of the state still have it (like Denver), maybe due to greed (they like that revenue) although I admit Denver's air is not as clean as ours.

You guys are funny LOL!!!...

 

Girls, you're all pretty! Now play nice

 

Simplest explanation
It's because of the mountain range. The easterly air flow acts like air flowing over a truck bed going down the road. The trash just keeps swirling around instead of being diluted into fewer ppm.
My solution, cut the mountain down to ground level in certain areas to let the flow through. Wouldn't need those overbearing policies then. (Not saying its ok to trash the place, but they could definitely ease the pain)

 

Bingo. Someone "gets it". That and the population density. Same w/the SLC Valley.

 

​​​​​​​Tom, have you found a cat that will fit your car yet?

 

But my clean air goes to 11!

 

Its not "as if" we really got you. It is there written and quoted multiple times. Your very first comment in this thread is, by every definition known to man, you making an erroneous claim.

 

Yeah? Well top ten is CLOSE ENOUGH.
Close enough that emissions testing has been proven unnecessary...

 

QUOTE=T.L.;6583678]Yeah? Well top ten is CLOSE ENOUGH.
Close enough that emissions testing has been proven unnecessary...[/QUOTE]



only top 5 states have the testing eliminated.

 

only top 5 states have the testing eliminated.[/QUOTE]

I am in Texas, they only test vehicles 2-23 years old and even then only in a handful of counties. Dallas/Fort Worth was an emissions area when I lived there. They so not even do emissions dyno testing on OBD2, just plug into the OBD2 and go. Having driven by it daily, the North end of DFW International was the smoggiest area in DFW. The smell alone would gag you. Commercial aircraft were the gross polluters not the average vehicle.

 

Testing is mandatory in VERY FEW places anymore. VERY VERY few. It's mostly managed at the local level; counties & cities. States have mostly got out of that since it's paid for at the municipality level, not the state level. I doubt there's many at all left that mandate anything about it, I'd bet no more than 10.

Meanwhile, it has NOTHING WHATSOEVER to do with "clean", as has repeatedly been ignored above. It's all about MONEY vs IMPACT, as has also repeatedly been ignored above. Plenty of places, like Grapevine as Fast mentioned, have decided that in spite of swimming around in POOP air non-stop, they can't be bothered spending the money to police it. Dallas itself is just as bad. Doesn't matter though, money is tight.

D00d, you come across like an 8-yr-old on the grade school playground, with that. When you get caught MAKING STUFF UP, just admit it, apologize, and move on. After all it's just the Internet, it's free, and nobody gives a crap anyway.

 

Jesus H. Christ you guys still going on about this?

It's like teenage girl drama up in this thread now.

 

I'd still like to know if Tom has identified a cat that will fit his situation, once we can get all the rest of this out of the way.

 

Good question. As you pointed out earlier, the bigger the cross section, higher the flow.

There is a complete take off exhaust system including cats for a C5 Z06 on our local classifieds. I'm going to buy that system and use those cats and the h pipe.

 

I think that's a great idea. Let us know how that goes. I'm curious where you get the cats mounted.

 

only top 5 states have the testing eliminated.[/QUOTE]

It was eliminated in my county almost 20 years ago...

 

Yeah, those Einsteins don't wanna let it go (LOL!!!)...

 

Except I didn't make anything up. I never claimed we were "number one" for clean air, just among the cleanest in the U.S., which is a FACT.
Apparently, some people here care enough to keep arguing with me about it (LOL!!!)...

 

It was eliminated in my county almost 20 years ago...[/QUOTE]


the top 5 states comment was sarcasm, cause this got crazy.

But, apparently we're all pretty, so i feel better now!

I am curious about how the cats get mounted though. Its actually something that I've considered on a few vehicles. Hell, i had a older deleted diesel truck i was thinking about putting a cat on to help w the smell.

 

Man, my head hurts and I started skimming about 1/3 of the way through.

Carb cats are just converters that someone put in the $$$ to get CARB tested. They cost more because of the testing so they have the number and can charge more to people that need them to be legal. There is no intrinsic design difference, though it is possible that some non CARB cats might not pass CARB tests but it's not likely that we'll ever know, care or matter for most of us.

Manaflow (there used to be other name brands like CarSound... they might still be around, not going to take the time to look right now), "high flow" cats started out as late 90's GM truck cat designs (OE and then later replacment), which were the first at the time that when used as a pair on what was even a healty V8 only cost typically 3-5hp.

Pellet bed cats were used well into the 90's by many manufacturers. I have the cat off my '92 Chevy K1500 Blazer in the bed of my dodge right now that is a big old pellet cat. F-bodies had them into the mid-80s, and they sucked.

The bullet cats, some of the metallic cats... anything that looks like a resonator... is mostly designed for difficult packaging, and if they flow OK they don't work great.

My $.02- get any straight through, late 90's or later cats off of a performance car or full-size truck, and a pair will likely only cost you a couple of HP each. For a while, I accumulated a lot of 4th gen parts and did a few exhausts with pairs of 96 and up passenger side cats (the driver's side bolted to the manifold and was a pain to use, but the passenger side was a nice, easy to use shape with a thick body and it sounded good. Something like a Magnaflow high-flow cat will be similar.

As far as the rest of this, no place has gotten rid of testing because their air was too clean (cleaner?), or not had testing and has cleaner air because of that. Clean air is mostly a factor of population density interacting with geography/weather, and not much else. Testing is largely a political and economic question and as far as I know tailpipe testing has mostly gone away because since '96 (95 in CA) OBDII has existed that pretty much reports if the O2 and converters are working, if the engine is putting out emissions within spec, so it's cheaper to just plug in a code scanener and if there are not set codes/flags and enough run cycles you pass. Less equipment to maintain and you can hire a burger filpper for barely over min wage and have them do it with almost no training. Now in many areas they make you self-test (MD does and has for years now), you scan your notice at a kiosk, and then plug the cable into your car and you do all the work, pay your test fee and you're good for X years.

Now if Tom wants to run cats what the heck do you care? Some people don't like the smell of uncatted cars, some have a sense of social responsibility not to add to the problem, and a well-designed exhaust with cats will cost less HP than most of us could feel or prove at the track. I myself have 2 3rd gens without, a '71 Mach 1 and Cummins that never had them, and then a bunch more with them. Reasons... I've considered putting a cat (or at least something that looks like one) on my TA just to save myself from headaches. I'm not sure that I could come up with a real performance justification for removing them in most applications in the future, but possibly financial, packaging, or possibly a SHTF justification.

 

The 1989 CAT's, or even 91 & 92, or they ceramic core? I can't imagine ceramic core rattling around so much. Sounds like metal, not dinner plates.

 

FWIW, I've owned 3rd gens since... heck, I got my first on in 1991 (no, I'm not that old) and my favorite exhaust was headman "shortie" (we used to call them 3/4 length, shorty headers are stock mustang 5.0 and corvette headers) into 2 "high flow" walker converters (basically late 90's chevy truck converters), flowmaster y-pipe, 3" pipe over the axle splitting into 2, 3" tailpipes... I don't know how many times I got "DOES THAT THING HAVE A BIG BLOCK IN IT?" about the sound the little crossfire 305 made... and that was well before LS swapping anything was a thing.

 

I've never seen an OEM cat that isn't ceramic, but I also haven't seen a bunch of stuff that's from the last few years. The only metal core ones that I've seen are aftermarket bullet style cats. The ceramic core is hard. Unless it's been severely overheated for a long time, it's not easy to break; it's more like hammering on a rock than on a dinner plate. The only reason that people manage to hammer or drill through them without using something like a jackhammer is that they are a square honeycomb, if that makes sense.

 

Oh, by the way, this might help someone:
Walker
Dynomax
some (a lot) of OEM stuff

It's all the same.

If you have access to the right catalogs, you can cross-reference them.

Weird facts there:
- Range Rover used to use Dynomax super turbo mufflers OEM but they were sold under a Walker part number, some years had dynomax on the case (turned up so you couldn't see it without cutting it off)
- Lincoln Town cars, some Crown Vics/Mercury Grand Marques, and GM B-bodies (Caprice, Roadmaster...) used the same Walker over the axle/tailpipe on one or both sides, depending on year and rear suspension version. You used to be able to get it as both a Walker and a Dynomax part number.

 

Car mfrs (GM, Frod, Xler, Toy Oatie, Honduh, Benz, ALL of em) are alot more just ASSEMBLERS these days, than MFRs. They DO make their own sheet metal and seats and stuff like that, butt things you can't really see and that don't really set them apart from other mfrs, they outsource. Even audio systems; Bose, Infinity, etc., the auto mfrs let them handle the details. Cheeeeeeper, more reliable, less trouble all the way around, to do it that way: let the specialists handle it. Brakes, exhaust, suspension parts, basically anything that doesn't provide "brand differentiation" in and of itself, is fair game for outsourcing. Consider TIRES as the perfect object model.

Dynomax is just a brand name that Walker uses for their "performance" aftermarket product line. Printing on a box, nothing more. Which of course is why if you look at a Walker catalog, it has a Dynomax section.. It's not as though Dynomax "sold under a Walker part #"; Dynomax IS Walker, just like Chevrolet IS GM or Lincoln IS Frod, so ... yeah.

The distinction between "metal" and "ceramic" is kinda a very fine yet very blurry line. The various elements (platinum, palladium, rhodium, etc.) that perform the catalytic function, don't combine into molecular forms, which of course is what "ceramics" are. Ceramics are mostly oxides, nitrites or nitrates, carbides, titanites, silicates, etc. of various metals that readily combine with other ions, such as aluminum, sodium, calcium, lithium, magnesium, occasionally silicon or barium, etc. In a cat, the "ceramic" or metal is only the substrate onto which the catalytic metals are deposited. AFAIK most "stock" converters, as well as nearly all "replacement" ones, have a ceramic substrate. The precious metals themselves aren't really "metals", in the chemical sense; they're transition elements, somewhere between "metals" and "halogens". Even common things we all like to think of as "metals" like iron, gold, silver, copper, zinc, chromium, ... to a chemist, aren't "metals" at all even though they kinda "look" metallic to the eye. "Metals" in that sense are mostly the elements in the first coupla columns of the periodic table.

That does seem to be true, for whyever... they're not hexagons like beehives or something. Not sure why. And yes, they are HARD. Which is probably one reason they're used; they won't melt, won't bend, and they're REALLY resistant to crushing.