idyfohu

Simple question.

Anyone have any issues passing emissions with Dundon Headers (to note, I'm running the OEM exhaust)? Quick drive thru test took 5 minutes on my wife's car, so the shop isn't putting the car on a lift etc. The system of course is catless, but couldn't remember if the OEM exhaust system had cats.

Hoping I don't have to spend the money to uninstall the headers, just to test, and then pay install to put them back on.

TIA!

Last_935

I'm not sure about passing emissions, as we do not have testing where we live. However, on the GT4 the cats are in the headers not the exhaust system.

Todd

cooler2442

What kind of emissions testing do they do? Most headers throw a code(I know a guy with Dundon on his GT4 that has a code) and if you get that code/they plug the car in then you will fail. Other emissions do a sniff test and if they sniff your exhaust then you will fail since the Dundon headers remove the cats.

If they don't do a sniff test and you have no code/check engine light then you should pass.

Errsomeone

Yes, I was failed. Local emissions are done every other year in my location, and even the annual tech technically requires a visual inspection. While the computer would have been fine, and know another local list member that passed on such basis, mine failed on the inspector being thorough enough to perform a visual verification as required to sign off on being done. There are ways that could have avoided such and expected to run into such but I decided to simply remove and comply.

TDT

OEM yes - Cat are integrated in to the header.

Dependant on your aftermarket header design... cats CAN been separate from the header and placed in a different location in the exhaust tract.
You could then make the cat module with bolt or v-band flanges that make it straight forward to remove and refit without unbolting the whole exhaust system or removing the header.
If so desired, you can then choose to run the car with a straight through test pipe for track, and put the cats in for street and emissions.
No Cats = code/cel unless you map it out.

Last_935

Agreed. Cargraphic makes a system that allows you to remove the cat portion of the headers and replace them with test pipes without removing the complete header assembly.

ajw45

I have no issues - DMS race headers passed OBD2 inspection scan with stock exhaust and GT3 exhaust with 3.8L and 4L engines.

brewerbry

It really depends. I have race headers with 1 O2 bung so to get around the CEL, I have an aftermarket tune. That tune puts the secondary O2 sensors in standby (not ready) mode; when I had emissions testing performed via the OBD2 reader, the testing system noted the senors were not in ready mode and did not pass the test. If you do not get a cel with the Dundon headers (which most don't because of the second O2 sensor bung) and you have a stock tune, you have a good chance at passing otherwise you might have to load a stock ecu map or install stock headers.

Good luck-

iammacey

I live in Georgia and had to get emissions done for the first time last November. I have the Dundon tune and headers. They plugged in the OBDII reader and performed a gas cap pressure test.

There was an error of some variety thrown, but he didn't state what it was for. Regardless, it passed.

Very state, county, and shop dependent. Especially in a state that is supposed to visually inspect for cats.