Cat-less headers and passing emissions
 

I was wondering if anyone has gone with a cat-less header, but kept a cat in the front pipe and relocated the o2s to in front and behind that cat? And if it would pass emissions and or set a cat efficiency code or not?

It'll be close with a quality high flow cat, but it *should* pass a sniffer test. If they do a visual inspection it depends on the state/province laws, up here we're not allowed to remove cats at all (can replace with high flow, but not remove entirely) but I've never seen a tech actually look to see if the exhaust was modified.

If the computer says the car is ok, the tech says the car is ok.

Yeah that's what I'm thinking. I just wanted to know if anyone has tried it and not got codes and if they have checked before and after with a 5 gas analyzer.

I still have a while before my inspection, but I'm running with a high-flow cat in my front pipe, and that's all. I'm a l little worried, since I've no idea what the machine will read, but I've got my stock parts still.

it really depends on state to state but as long as no visual inspect and NO CEL, then you should pass

Have you had any codes set? Did you do anything to trick you're 02 sensors?

I did have codes, but they were from the car running rich. tune fixed that, and cleared it out.

Awe ok, you had it tuned.

The inspector's scanner also checks for readiness, so no CEL does not equal pass.
Someone should offer a secondary cat pipe with a post O2 bung, it hasn't been settled whether ECutek tunes that turn off the CEL actually clear the readiness checks.

Sorry for being off topic but this is one reason I like NJ and having a new car. No inspection required for 5 years :D still have 4 years and 4 months until inspection. Just keep holding on to all my stock parts. Keep them if you can, it'll save you in the end.

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Amazing that PA requires the ODB inspection every year on all cars, stricter than NJ, such a racket. So many poor people around here can't keep their old reliable transport due to stupid OBDII codes. Most of the flags with old cars are just bugs and not causing pollution.

Maybe in 4 years the romraider guys will have an open source flash for these cars that always pass the scanner!

But this platform really ahouls have aftermarket secondary cat pipe with a post O2 bung, would allow catless header and be 100% legal (no "off-road" tune required.) You know those stock manifold cats will be the first thing to go on this car emission's wise, so pay for it a nice catless header/secondary cat pipe now or pay later.

Yeah play later alright. I don't know what the fines are in my state if you personally modify the cats but the fine for a shop to remove, I was told awhile ago it was like 10,000 fine to the shop. Really would have to look up the current laws to be sure tho

Its different here out East, they just scan the ODBII. I don't know what the laws are out west but I know that with the MR2-Spyder the first mod everyone does is remove the manifold cats as they are prone to breaking down and then the ceramic finds its way into the EGR and the engine. Also the 05+ turbo foresters require the header cat to be removed because they break down and destroy the turbo.

Just two examples of common engine failures due to cats close to the engine.

So it would be nice to have an O2 bung after the secondary cat, that way one can install a header and still of the ECU monitor the condition of the existing cat.