What is a test pipe?

[KCz Eclipse]

Okay, the title pretty much says it all. Does a test pipe go inside the cat? What is the purpose of the test pipe? Don't you have to have a cat to pass inspection?

 

[stacked1G]

a test pipe, also known as a "straight pipe" goes in place of the cat..it helps free up restriction in your exhaust.

yes you need a cat to pass inspection, unless you know someone or your car is a 94 or earlyer i think, they dont needa do emissions anymore(atleast here in MA)

 

[IrishBeatdown]

Does a test pipe go inside the cat?
No it replaces it.
What is the purpose of the test pipe?
More flow instead of a restrictive cat
Don't you have to have a cat to pass inspection?
Yes, but there are way to tune around the cel and items like this to get around the visual:
Catalytic Converter

 

[victorious420]

A test pipe replaces the cat, and has no restrictions like the cat does. The purpose of the test pipe is so you can have a full exhaust without having a cat causing exhaust restrictions. A test pipe won't pass smog, many people keep a cat around and switch it with the test pipe only on smog day.

 

[BogusSVO]

A test pipe is just what the name implies, it is only for testing pourposes.

It is used to check for a clogged cat.

1)Remove cat from car
2) install the test pipe in car
3) check for drivabilty issues that a clogged cat would cause ( excessive back pressure)
4) Remove test pipe, either install the old cat back in car if the test pipe did not help, if it did, install a new cat.

Now... since you are your own mechinic, it is up to you how long you need to have the test pipe in place to do the tests to confirm if you do have a clogged cat.

But by federal law, every car made after some time in the 70's is supposed to have a cat installed if used on public highways and roads.

 

[Bud92gsx]

^ I think it's 72. My buddy has a 72 dart swinger, and it does not have a cat on it. As far as we know besides the paint, the whole car is origanal.

 

[victorious420]

Google is your friend. It will help you get rid of those red chicklets. Google is way better than "I think...."

Catalytic converter - Wikipedia, the free encyclopedia

 

[KCz Eclipse]

Why couldn't you just get rid of the crap inside the cat and weld it on just as you would when it was normal?

 

[BogusSVO]

Why couldn't you just get rid of the crap inside the cat and weld it on just as you would when it was normal?

Beacuse it would be illeagl.....

But I am sure there are a few cars on the road that have a hollowed out cat...

 

[Bud92gsx]

Google is your friend. It will help you get rid of those red chicklets. Google is way better than "I think...."

Catalytic converter - Wikipedia, the free encyclopedia

I think I was 3 years off, on something that has nothing to do with our cars.Ours "have" to have a cat by law


I'm not sure I know too many people that still have a stock cat. I've also never heard of a policeman looking under a car for a cat.

And we don't have emissions, So that could be why I've never heard of it here.