Straight pipe instead of new CAT

[alkemist]

Hey,

My 96 Buick Rivieras CAT began to rattle recently. It sounds terrible when I give the car some gas.

Considering I will not have a problem obtaining inspection in the future... and to same some dough, should I replace nthe old CAT with a straight pipe?

[GreyGoose006]

you could, but it would probably be illegal, and cause you to fail emissions

[turtlecrxsi]

It will most likely be louder with just a straight pipe.

[UncleBob]

aftermarket high flow cats start around $50. Assuming its a replaceable type cat, I can't say there's a good reason not to just replace it.

btw, if you do gut the cat (or replace it with a straight pipe) the check engine light will come on and stay on.

And also: badly burned out cat like you discribe, usually points towards a long term runability issue, such as misfires

[curtis73]

I agree with UncleBob. Buying a new cat is often the same as having an "export" pipe fabricated to fit in its place. On almost all cars after about 1989 have honeycomb style cats that usually don't cost a single HP, but they do incredible things for the atmosphere. I'm not one of those super-conspiracy pollution freaks, but I'd rather do the "right" thing instead of finding out later that car emissions really were a big deal and I should have left it on.

Can't hurt, not much money, legal, I suggest you do the cat.

[UncleBob]

hehe, I won't bother preaching about emissions. Really, I think its a question of price. There are some cars/trucks that its $1500+ to replace a cat, and if your state/county has no emission testing, heaven knows *I* wouldn't replace it if it was my vehicle.

We all have our breaking point.....

But if its cheap, easy, and the same amount of work either way, then its simply the right thing to do. Cats DO clean up the emissions significantly. They don't have much effect on performance (although many believe otherwise) there's just no good reason not to replace them....when its reasonable.

This state/county though, you wouldn't be able to get your tabs like that, so you wouldn't have any choice here, even if the cat cost $1500+ to fix.

[curtis73]

I have to laugh also at OBD2. I have a 96 Impala SS which shares the same exact cat as the 94-95 OBD1 SS's. I can buy a 94-95 cat for $125, but to get the part number that carries an OE exemption number is $649... And in CA, I'm not technically allowed to swap them until they've made me fail emissions, and THEN I have to to to a test/repair station and have THEM do the work.

I don't know which side of the fence to be on right now, either. I do believe firmly that fossil fuel emissions are a problem, but evidence suggests that vehicles aren't the main issue. I do have a problem with dragging HC from under the surface and vaporizing it into the atmosphere, but its actual effect is vastly different depending on who you talk to.

But I ramble

[alkemist]

Guys I really appreciate this in-detail info.
If theres not much price difference, Ill do the right thing... I plan to sell the car in the future anyways.