I've read multiple threads on this topic but still have some confusion. Maybe reading so much has lead to confusion.

I drive a '96 Civic DX and my son drives a '98 Civic LX. Both have the D16Y7 engine with the one piece exhaust manifold & catalytic converter. Both exhaust manifolds are cracked.

Regarding California:
Assuming all the work is done properly, is a full DX/LX exhaust system conversion to EX legal in California? If not technically legal, do smog stations let the visual inspection slide?

Regarding welding as a solution:
A muffler shop that my son has gone to in the past has an excellent reputation. The shop is owned and operated by one man with over 30 yrs experience. He claims that he has had good success welding cracked manifolds compared to other shops. The shop is near my son but 400 mi from me. Is this solution worth a try or doomed to failure?

Regarding replacement as a solution:
Anyone have long term success with a CA legal aftermarket part? If so which specific one?

Thanks and sorry for laying out a dead horse.

 

Anyone have experience or an opinion on the following CARB legal, direct fit manifold/converter units? Which are likely to last a long time and not throw random codes?

My impression (only from the photos) is that the Magnaflow and Bosal header sections look like they are not likely to crack. They may have other problems I am not aware of. The Catco and Dorman headers look like a design similar to Honda's original. (Click to slightly enlarge)

Magnaflow 56029


Bosal 0899100


Catco 612340


Dorman 673439


Honda 18160-P2E-A12
(you know what this looks like)

 

Magnaflow is usually OK quality.

I'm pretty sure an EX conversion is legal, of course you must use only stock or CARB-approved parts.

 

Thanks for your feedback. That's the one I'm leaning toward.

On further (but not final) research, my reading of the "new" 2009 CARB laws are that the EX conversion would not be legal in CA (see below). That said, I contacted CARB to ask them. I will post the answer if I get one.

 

Even I think so that both the Magnaflow and Bosal header part looks as if it will not crack easily. I agree to the point what Ski - T says and it's just the assumption made. Further I would like to go for the details. Please do mention in details.

 

For some cars, such as my '96 Civic DX and '98 Civic LX, Magnaflow makes 3 different grades of catalytic converters, a standard grade, an OEM grade, and a CARB grade.

From their web site:
I asked Magnaflow if the CARB grade was as good as the OEM grade. Basically they said that it is the same converter, but has obtained CARB approval and has the proper CARB identification stamping.

 

I decided to install a CARB legal Magnaflow 56029. I haven't received it yet, but it is supposed to come with the upper and lower gaskets. When I remove the old manifold/cat are there small rusted or damaged parts that I am likely to need to replace? For example, the nine nuts (#12) shown in the figure below? How about the three bolts (#5)? Are there nuts that go with those bolts? How about #1, #11, #14 and #15? Thanks.



To finish a previous post in this thread, I never heard back from CA Air Resources Board about the legality of installing an EX cat in an LX or DX. However, after reading their web site more thoroughly, I'm pretty sure it is not legal. That said, the smog check station I talked to said it was unlikely that anyone would notice unless the exhaust was loud or attracted visual attention.

 

You're almost certainly going to need new studs at 5 and nuts. There is also a gasket there where the converter attaches to the first pipe. The ones at the top (12) where it attaches to the engine may be reusable. All those parts should be available at any local parts store.