anewstatic

I'm considering removing the cat converter from my 80 and replacing it with a bolt-on test pipe. I live in Idaho and cars built before 1981 don't require an emissions test (score).

My question is this... Is there any legal consequence for removing my cat converter? I know shops can't legally remove cat converters because of federal law but I'm wondering if I could be in any hot water doing it anyway. I'm not afraid of federal agents inspecting my car or anything but is there any risk involved at all?

Also, I know removing the cat can produce a slight increase of HP and mpg. I've read other threads of some of you being pleased with the results. But are there any negative consequences?

Only thing I read in the thread had to do with sound but I have two flowmasters on my car right now. I love the rumble and don't want it to be lessened. Any risk of that?

Thanks!

Easy Mike

Check with your DMV. They should be able to give word on the legalities of removing an emissions device.

rcread

If you do any traveling, some places are now doing random smog checkpoints. I know California is one of those states, and within reasonable driving distance from Idaho.

82CFI

If you did, I wouldn't announce it. Like on any public forum.

Disclaimer: I'm not an attorney ... just another fellow citizen with a little common sense.

States penalize residents for not passing smog tests by denying them a vehicle registration. Without the registration (license plates), you wouldn't be able to drive your vehicle too far on the roads/highways. Seems that you're exempt in ID.

If you visit CA from ID, you will be waved on to bypass the "surprise" check station by the officials standing there because they will see your out-of-state plates. This is what happened to me with my NV plates although I did still have my CAT.

One last thing: I wonder about public admissions on the Internet regarding violations of Federal Law and how the NSA is gathering everything on the Net ... simple for the federal attorney to just dial into the database and get your "confession" for a successful prosecution when it's discovered (and reported) that your vehicle doesn't have the CAT anymore. Hate to be a Debbie Downer on your question.

Roughrider

You can always install a modern performance cat...they're not that expensive and don't restrict flow like early ones did. Check with Summit Racing or Jegs and see what's available.

scottyp99

I'm not advocating doing this, but let's say, hypothetically, you were to remove your cat, ya know, to inspect it, and while you were inspecting it, you accidentally jammed a big pipe into it. Let's further assume that you are very clumsy, and accident prone, and you kept accidentally doing this, over and over, until all the guts crumbled and fell out of the cat. Then, maybe you went back in the house, cleaned up, made a sandwich and ate it, watched some tv, and forgot all about the accidents with the cat and the pipe. Then you went back out into the garage and re-installed the cat, because you didn't remember that it was just a big, empty shell now.

If this particular series of events were to take place, then you would have a more free flowing exhaust system, which would be just a hair louder, and anyone who looked under your car would see the original cat sitting there, just as pretty as you please. No one would be the wiser. Not even you, because you forgot all about it. All hypothetical, of course. I would never advocate doing anything illegal. I'm a good boy. I drink the Kool-Aid, just like I'm supposed to.

Scott

doorgunner

As much as I despise Cats (because the older ones do rob performance).....I installed dual exhausts on my '34 SBC truck and also installed (2) hi-flow Cats designed for a 3.0 Liter engine...(3.0 liters per bank on the SBC) to keep V.P. Gore's atmosphere clean.

I ended up NOT needing mufflers...imagine that.....the sound is deep, but not loud....no problem hearing the radio....the intake can still be heard on moderate acceleration (all bets are off on hard acceleration though )

anewstatic

I like where your head is at.

Snoopysvet

tektrans

Other than the legal downside another downside is the damn fumes.

82CFI

Gotta laugh. Scott can really write a damn good story line, as good as any I've heard and plausible too.

7T1vette

I really don't know what EPA laws are applicable on a 30+ year-old vehicle. But, I believe that removing a CAT for any reason (and not replacing it with a similar item) is still illegal. And, you have to agree that your car's emissions will significantly increase if you do so (and the present CAT is functional).

If you have emissions inspections in your state/county for the C3, then you really HAVE TO replace it with another CAT or you will fail the emissions test (visually and functionally).

If you don't have such tests in your area, then you just have to decide what is important for you.

scottyp99

Here's an article on how catalytic converters work, and what they actually do:

http://en.wikipedia.org/wiki/Catalytic_converter
Even a well-tuned engine will produce a few hydrocarbons and some Carbon Monoxide, and if you have advanced your timing for performance, some nitrogen oxide. Modern catalytic converters convert these into carbon dioxide, water, oxygen, and nitrogen. I' am thinking of installing a couple under my car, even though there is no emission inspection in my state for cars that old.

Scott

doorgunner

Back in the '80s my Cutlass failed the state emissions test.....

I went home/removed the cat/installed a test-pipe......it then passed the test!

I had a new Cat installed the day they went "on Sale".

Capt. Shark

I'm wondering if you would really fail the sniff test with no cat if you cranked back the timing and let the engine idle for a while to heat up a little more. The last few times I got my car smogged, the numbers were well below the max limit.

hardlanding

http://www.thirdgen.org/techboard/ex...catalytic.html

great write up with links to the EPA

hardlanding

Useless piece of info, I am leaving my smog equipment on the car because i think it will effect the value down the road if it is removed

Iceaxe

I bought a Z-28 new in 1980. My first mod to replace the cat with a test pipe. The car sounded better and the performance increase was very noticeable. I'm guessing the 80 vettes and 80 Z-28's had the same/similar cats. Anyhoo.... that was my experience, your mileage may vary.

FWIW: The Z-28 would pass the required sniff test without the cat. At the time Utah law was if you could pass the sniff test you were golden, that law has since changed.

jb78L-82

Here is the skinny:

Removing ANY emissions control equipment including a cat (or non emissions carb, EGR valve, heat riser valve, AIR pump etc) on a car that came from the factory with said emissions equipment is considered illegal under FEDERAL law and of course, each state has there own requirements as well. So even if your state does not require emissions testing, technically speaking a law enforcement officer could break your chops if a cat was missing in a state that does not require testing. Would that happen, probably not but….

As for folks that run dual cats on a dual exhaust system on a car that originally did not have true duals, well that is considered illegal also under Federal law since the car did NOT originally have duals. So folks that run dual cats say on an 80 vette with 2-1-2 exhaust, illegal as well. A little less illegal but still technically illegal.

As others have noted, dual high flow cats on a true dual exhaust system will negligibly effect power but will of course, cost more money since you have to buy 2 high flow cats and have them installed if you cannot do it yourself.

No comments on my 78, but on my 94 Mustang GT Convertible I have shorty headers with a magna flow X pipe with 4 cats (2 pre cats and 2 high flow cats) with magna flow mufflers and the thing screams at high RPM and sounds awesome.

If I lived in a state that required emissions testing, I would put on 2 high flow cats on the dual system and call it a day, except of course if you lived in California or Canada, places that seem to enjoy enforcing the letter of the law.
Your call?

maverickmk

Hmm, this sounds vaguely familiar. Maybe it was a dream?