The Nissan Path

Looking to replace my primary cats as they have failed, honeycomb has broken into pieces and is stuck in the rear cat / resonator. Looking for a decent cat that you may have had success with and / or brands to stay away from. Also I'm looking to into the DT Mid Pipes (Part Number 83206-B) after the cat and then possibly a gibson cat back. Just looking for some feedback as to how this should work out. Thanks in advance.

- Justin

For catalytic converters, Walker Ultra converters and Bosal are good brands. The DT mid-pipes are good quality and are direct-fit replacements for the rear converters. If your state has strict emissions testing, they may not pass as they are technically for "off-road" use. Removal of converters is considered as tampering with a federally controlled emission device, thus technically illegal for street use. If you inspection is pretty lax where you live, they probably won't give you any problems by having them installed.

Hey SMJ,

So if I went with the Thorley long headers and the mid pipes, I'd have no cats at all, right?

Do they have a bung for the F/A sensors? I don't see one in the pics... (EDIT: I just noticed there is a port for the F/A sensor in a different pic on the long pipes... intriguing!!!)

Hmmm... we don't have emissions here, wonder what kind of performance change I would notice... Or sound for that matter..



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I went with the DT shortie headers and mid-pipes, keeping the upstream converters. If you go with no converters, you'll have to get a custom ECM tune from UpRev for two reasons. First, without the upstream converters, the P0420/P0430 catalyst codes will constantly trigger. Second, without the converters, these engines for some reason tend to run too lean, from what I've read. And, "yes," there are bungs for the O2 sensors.

smj999smj wrote:I went with the DT shortie headers and mid-pipes, keeping the upstream converters. If you go with no converters, you'll have to get a custom ECM tune from UpRev for two reasons. First, without the upstream converters, the P0420/P0430 catalyst codes will constantly trigger. Second, without the converters, these engines for some reason tend to run too lean, from what I've read. And, "yes," there are bungs for the O2 sensors.

LOL I already have the P0420/P0430 codes all the time. Seems my cats are getting old. Interestingly enough, they don't trip the code while cruising, only on cold start when driving in town or short distances. Once I have my cruise set to 70MPH, I can reset the CEL, and it won't turn back on until I stop the engine, let it cool, and restart it.

I probably won't get out of changing the cats, if we keep the truck for too much longer. And you can't buy used cats from the wreckers here either, illegal to sell them apparently.

What I've heard is I could 'trick out' the ECM by using some spark plug anti-foulers on the secondary O2 sensors. This would pull the sensor out of the exhaust stream enough that they don't trip the P0420/P0430 code.

The other thing is that I've never replaced the O2 sensors. I have replaced the F/A sensors, but that was over 4 years ago. Wonder if the O2 sensors are getting weak, the voltage seems to jump around a fair bit, and I've read that they can become lazy, which would also trip the codes I'm seeing.

Sounds like I need to probably fix/replace the cats.

My left bank converter was doing the same thing as yours. I put an oxygen sensor spacer on the rear sensor on that bank and it only trips the CEL about once a month, compared to every 3-4 days without it. I used a straight spacer, but I wonder if a 90-degree spacer might have eliminated the CEL altogether? Anyway, the spacer I got from Amazon was about $10...easier and cheaper than replacing the converter.

smj999smj wrote:My left bank converter was doing the same thing as yours. I put an oxygen sensor spacer on the rear sensor on that bank and it only trips the CEL about once a month, compared to every 3-4 days without it. I used a straight spacer, but I wonder if a 90-degree spacer might have eliminated the CEL altogether? Anyway, the spacer I got from Amazon was about $10...easier and cheaper than replacing the converter.

Thank you so much! It's very helpful!