Cat or Test Pipe?

[drewusmaximus]

Hi all,

I have a 1989 SE hatchback. it's obvious that it's not OBDII. I live in upstate NY. The car is not inspected yet but, I'm wondering for inspection sake should I get a CAT or a test pipe? I called a shop and they said, since it is an 89 the inspection will be based on safety i.e., lights, brakes, signals, etc.

I have a mechanic who has done the inspections on all my cars for years but, I'm just looking for advice on which route I should take.

Thanks in advance.

[JayArr]

Cats are expensive, I think the answer to your question may be a matter of economics. If you own a Cat and it's a high flow type then put it on, it's free. If you don't own one then a test pipe would be cheaper. On an 89 I can't see it making a performance difference.

[drewusmaximus]

I noticed it's not a direct bolt on. The test pipe is 3 inch. The flanges do not match the flanges on the stock exhaust. So, do I have to buy a complete 3 inch exhaust, from the down pipe to the muffler? or is there something I'm missing?
I'm confused. If 3 inch catback exhausts are being sold how are 240sx owners installing them on a stock cat that is 2.5 inch outlet flange?
Now the 3 inch test pipe will directly bolt on to a 3 inch catback exhaust but, it can't directly bolt on the downpipe since it's 2.5 inch.

I apologize for being confused. I'm a noob. I must be missing something.

[GTR PrYdE]

A 2.5" or 3" cat or test pipe will bolt up, the flange outer dimensions are the same. I'd go with a high flow cat, as test pipes stink horribly IMO.

[drewusmaximus]

Agreed. I already have a cat on the exhaust. The PO welded the cat to the down pipe flange. So, I have to cut by the flange because there was a leak at the seam. i'm going to keep the cat because the other side of the cat is in tact and worse case scenario, I weld the cat back on. But for now I'll throw on the test pipe with the catback exhaust that's on it's way.