cats vs. no cats

[94ponform]

I was just wondering what the difference is between running an ory or running your cat. How much more do you actually gain by runnin the ory. Logic says that with no cats, it would be a more free flowing system. I plan on gettin those LPP headers and y, so i'll be getting rid of my cat anyway. Just wondered what the gains are for the ory over the cat.

[YZF]

Cat... uh... what's that? Er wait.... nope.. never had one lol.

[Z28pr0jekt]

for most people, it just depends on their state regulations... i personally dont run any

[HoLLo]

There's not gonna be a difference in performance that you are actually gonna feel. Right now I am debating whether or not to actually add cats or just weld some heatshields to my ORY to pass emissions..

[94ponform]

well i knew some people have to pass emissions. thanks HoLLo, that answered my question.

[YZF]

Man it would really suck to have to pass an emissions test. In MO, we are required to have a cat in every car made after 1981.

[jaysz2893]

Sorry for the long winded answer..

WARNING: Federal law makes it illegal for ANYONE to tamper with, disconnect, remove or otherwise render inoperative ANY emissions-related control device. The Environmental Protection Agency and most states have actually been rather lax about enforcing this rule on motorists, but they haven’t hesitated to nail professional service facilities that have been guilty of tampering. Even so, the fines can be hefty. A violation may make you liable for up to a $2,500 fine!
No Tampering

The federal anti-tampering law does not, however, apply to race cars that are not operated on the street, other full-time off-road vehicles, show cars that are not street driven, or vehicles not factory equipped with emission controls (most 1967 and earlier vehicles). So that exempts all antique cars, and most classic cars and muscle cars.
Revisions to the Clean Air Act in 1990 further broadened the definition of emissions tampering to include virtually ANY type of engine or exhaust system modification that alters what comes out the tailpipe. That means any nonstock aftermarket part that is installed on your engine must be EPA-approved and emissions legal (except on the exempt vehicles previously noted).
Before the law was revised in 1990, it was only illegal for professional mechanics to remove or disconnect emission control devices. There was nothing to prevent a motorist from tampering with their own vehicles. That loophole has since been plugged.
What Is Emissions-legal?

Any of the following may be considered emissions tampering and get you into trouble:
Removing the EGR valve or plugging its vacuum lines
Removing or disconnecting the PCV valve
Removing the stock air cleaner and heat riser duct plumbing
Removing the catalytic converter
Removing or disconnecting the air pump
Removing or modifying the stock distributor vacuum advance/retard
Altering the stock ignition advance mechanism or timing curve
Replacing the stock distributor with an aftermarket unit that is not emissions certified
Modifying, removing or replacing the stock computer or PROM chip with a non-certified component
Blocking the heat riser duct under the intake manifold
Knocking out the filler restrictor on the fuel tank inlet pipe
Replacing the stock non-vented gas cap with a vented cap
Removing or disconnecting the fuel vapor recovery canister
Changing the idle mixture or stock carburetor jetting
Removing or modifying the carburetor choke
Modifying or replacing the carburetor accelerator pump with non-certified components
Installing an intake manifold or racing manifold that lacks provisions for the stock EGR valve and/or a heat riser duct
Installing a carburetor that lacks the stock emission hookups
Installing non-certified fuel injectors
Installing a long duration "racing" cam that is not emissions-certified
Installing exhaust headers that lack provisions for a heat riser valve, an air cleaner preheat stove or fittings for an oxygen sensor (if required)
Installing valve covers with open breathers or no fittings for a PCV valve
Installing any induction, fuel or ignition system component that is NOT emissions legal
Aftermarket parts manufacturers who make nonstock performance parts for engines, the fuel, ignition or exhaust systems must apply for special certification for any parts they want to sell as being emissions-legal. The California Air Resources Board (CARB) has been the leading government body in this respect, so most submit their proposals to CARB.
First, they must submit detailed proof in the form of laboratory dyno test that document their part does not have an adverse effect on exhaust emissions. These tests are very expensive and must conform with specified test procedures. CARB then reviews the data and may or may not ask for additional information and/or testing. If the product meets CARB’s criteria, CARB issues an "executive order" (EO) number (also called an "exemption" number) certifying that the part is in compliance with the applicable clean air rules.
An EO number means the component can be legally manufactured, distributed, sold and installed on a street driven vehicle in the state of California. It also means the component is legally acceptable in all 50 states because the federal Environmental Protection Agency also recognizes the CARB exemption program as meeting their "Memorandum 1A" requirements for certifying emissions legal parts.
Buying Emissions-legal Parts

Virtually all stock replacement parts are emissions-legal regardless of who makes them. But if you’re buying any nonstock performance parts, heed the following to make sure you’re "safe" from an emissions standpoint:
* Look for wording on the box that says the product is emissions legal or emissions certified for street use in compliance with the EPA and/or CARB rules.
* Look for the EO (executive order) exemption number issued by the California Air Resources Board on the box, product or in the catalog. Remember, the product must have an EO number to be street legal.
* If there is no EO number and one is required to be street-legal, it cannot be legally installed on a street-driven vehicle. Period.

[joelster]

Lol, there's the politically correct post.

I live in NY, and OBDI cars go through a "visual" emissions check only, no sniffer, no plugging into the computer, etc....

Any car '96 and later must get plugged in where I live, different states will vary, but trust me, EVENTUALLY all of the states with relaxed-requirement will follow, it's only a matter of time.

As far as performance is concerned, you will gain a few ponies, nothing drastic, but it is free. I did one time see a back to back dyno run, with a catted car then a hammered out empty cat, and it picked up 2-3hp iirc. I did it to my car when I first bought it, and I can tell you one thing for certain, The sound was amazing compared to how it was with the cat in place. This was stock manifolds, going through the stock cat-back. My car sounded great. It's so easy to do, only takes about 30 minutes. Plus with it still up there, my car will pass a visual emissions check.

[Z28pr0jekt]

Lol, there's the politically correct post.

I live in NY, and OBDI cars go through a "visual" emissions check only, no sniffer, no plugging into the computer, etc....

Any car '96 and later must get plugged in where I live, different states will vary, but trust me, EVENTUALLY all of the states with relaxed-requirement will follow, it's only a matter of time.

As far as performance is concerned, you will gain a few ponies, nothing drastic, but it is free. I did one time see a back to back dyno run, with a catted car then a hammered out empty cat, and it picked up 2-3hp iirc. I did it to my car when I first bought it, and I can tell you one thing for certain, The sound was amazing compared to how it was with the cat in place. This was stock manifolds, going through the stock cat-back. My car sounded great. It's so easy to do, only takes about 30 minutes. Plus with it still up there, my car will pass a visual emissions check.

Unless you have friends at the shop... lol i have no egr/air no cat and just the slp bullet muffler with race longtubes... :-D i love passing ny inspection lol

[joelster]

Unless you have friends at the shop... lol i have no egr/air no cat and just the slp bullet muffler with race longtubes... :-D i love passing ny inspection lol

x2, how do you think I get mine to pass? ;) Friends at the shop can help with an OBDI car but there's nothing they can do about an OBDII car that gets plugged in and fails.

That's why I recommend ANYONE who is looking to buy an LT1 car to try and find a '94 or '95 first.

[Masoch]

What I've found is that cars with cats generally have less rasp and sound a little more elegant vs cars w/o cats that have a larger amount of rasp and a more "all American" noise to them. So I s'pose its a matter of taste in terms of sound.

As far as gains, yeah a few ponies. Right now my 383 has a hi-flo in it and I really only keep it because it keeps the car from breaking noise ordinance, lol.

Hollowing may be in my future because I have no friends, lol.

[Camaroz2894]

What I've found is that cars with cats generally have less rasp and sound a little more elegant vs cars w/o cats that have a larger amount of rasp and a more "all American" noise to them. So I s'pose its a matter of taste in terms of sound.

As far as gains, yeah a few ponies. Right now my 383 has a hi-flo in it and I really only keep it because it keeps the car from breaking noise ordinance, lol.

Hollowing may be in my future because I have no friends, lol.


yep i have no cat.. and it's sounds alott better... deeper sound better flow HP gain ah... sure how much though dont know... :)

[McCauleyWB]

I hate you guys.

Sorry, I take that back. I hate California...I envy you guys.

[landstuhltaylor]

It's all about finding the right shop. Here in MA it's supposedly pretty strict but my car still passed because I went to a lazy shop. I have longtubes, ORY, !EGR, !AIR, a check engine light, as well as low coolant and oil lights staring me in the face. If you find a shop that lazy, you don't even need to throw them a $20.

[squeals99]

if i were you i wouldn't do it if you just have the stock piping and just want to hack it off... thats how mine was, except i had a hooker muffler in place of my stock one and it sounded so raspy and terrible that i couldnt stand it and had a glasspack welded in its place till i could afford the magnaflow catback... and that replaced my pipe after the cat from 2.5'' to 3''

[bricez28]

Any of the following may be considered emissions tampering and get you into trouble:

....i am in so much trouble lol.

[bricez28]

when i bought my car some guy hacked the cat off and put in some crappy pipe, thats why i barely have exhaust cause i wanted all his shit goneeee

[Neil350]

In Texas no one cared for a long time, now they are trying to flex nuts, modified cars are easy targets for no cat tickets. It's even harder to get a smog sticker then it used to be.

[bricez28]

yea, my car goes on a dyno and its a 94 and i live in new york. but i to have a friend at the shop, who will scan my registration, and then run a different car on the dyno.

my last car i just unbolted the exhaust, took a big screw driver and hammer, and smashed the fuck out of it till it was empty lol

[Fixxer99TA]

The Hawk will have LTs/ORY next season with the LE2 Heads/847 Cam, only because my friend does the emissions for me....

MA is pretty strict with the emissions stuff, but theres always a way around it. Only thing I have to worry about is running into a cop that minds the noise :D

EDIT : Yes, my car also has to go on the Dyno, but I passed fair and square this year with the Hotcam and Mids/Single cat. Next year wont be so easy though, might have to put a new Silverado or something on there for me :D

[22lambo]

I hate you guys.

Sorry, I take that back. I hate California...I envy you guys.

LOL, I know how you feel. I live in CA too :cool: