Hey everyone, first post, thanks in advance. I wish this wasn't my first post but thats how it goes. I am planning to do some serious traveling to buy an RX8 tomorrow and have some concerns. I have owned an RX7 (FC) in the past and have always been a rotary fan, so this is a nice next step.

So for those who own RX-8's, do you guys ever have trouble passing smog? I have heard that RX8s specifically are actually very good when it comes to passing unless there is a serious issue.

The car in question has under 100k miles with a dealer installed engine with less than 7k. The owner has tons of documentation from the nearby Mazda dealer​ documenting the last 100k miles. Oh, and its a Shinka trim with the black cherry paint.

HOWEVER, the car has aftermarket headers and exhaust that were installed recently and has a CEL. The owner has paperwork proving he had the thing smogged (pre-headers) about 5-6 months ago but lovely CA requires a smog within 90 days to transfer the title. He claims he will have it smogged tomorrow, but it is a 3 hour drive for me and I have a feeling he couldn't swap the manifold that fast.

If the thing wasn't so gorgeous and well documented I wouldn't bother, but I am pretty sure if I don't buy it someone else will. I have an OBD2 code reader so I planned to check the codes to verify it is an O2 sensor that is throwing the CEL, but is there any chance this thing wouldn't pass once a stock manifold is put back on (besides cats being no good)?

 

If you give the CA inspectors a reason to do a visual inspection, it won't pass smog. It will pass the sniffer test if you get a working OEM cat on there, even with an aftermarket header. There is nothing the header does/controls when it comes to the sniffer test. You will obviously need to get the reasons behind the CEL solved, there may be more than 1 code in there. I would have him give you the codes before you travel out there. If he isn't able or willing to get the specific code numbers, then it's a huge red flag to worry about.

The OEM cat is $300-$500 on here if used, otherwise $1,300+ at a dealer. I am not aware of any specific aftermarket cats that could make the RX-8 pass a sniffer test in CA, though there might be some. Front O2 is ~$250, rear O2 is ~$150. Those codes are really important though, since by definition they are what you need to solve.

 

I'm unfortunately clear on the smog laws in CA having had many cars and several that wouldn't (or never) passed smog. Most cars 2005 and later don't even get a tailpipe test, just a visual and a CANBUS scan.

So although the lack of a cat should make it fail a visual, in the end it's the CEL that will make it fail. Assuming it can be traced to the o2 that should be an easy fix.

Also, I would like to point out I have no intentions of trying to fake the system here. My intent is to put the manifold back to stock so I don't get the CEL in the first place.