Car Inspection
 

Somebody set me straight. I live in Denton county and I want to put headers on my car. Do I have to put cats back on to make it legal? I know I can tune the rear 02s out. But, is that legal? I've heard it both ways. Thanks.

My understanding is that any county that ajoins/touches either Tarrant or Dallas county is in an EPA "non-attainment zone"

means full inspection with sniffer

so that means they are also supposed to do a visual inspection even if the sniffer test gets passed

I live in Hood that (right now) is safety equipment check only

Long tube headers are not legal anywhere. Saying that, I had them on my 99 Z28 with cats and never had a problem. LT's with cats and tuned will pass unless they look under the car.

How are they illegal if it passes the sniff test and the cats are in place?

You have modified the factory emissions equipment.

Sorry but that is wrong. You can replace cats on any car without penalty. If that was the case then you would have to throw away your car when the cats fail or get clogged. You don't have to go back with OEM parts. They do sell aftermarket cats and other emission parts and sensors.

The poster is talking about replacing the headers as well as the cats which in most cases with require a engine computer reprogram to turn off the rear O2 sensors to avoid a CEL and accompanying codes.

All of which is skirting the intent of the Emissions Laws, but like most of us who have done it, like speeding or running without a front plate, we take the chance.

Yes, you can replace them but not modify their location or the way they operate. Like mentioned above, you can get away with it. I never had a problem with mine. Car was tuned and the rear cats "deleted". Per the law that is illegal.

Tom and everyone.

Me I don't like Cats in my exhaust , Cats with Fur, okay !! The hill that I drive up to get home is 3 miles uphill, very winding road, narrow, Deer etc, sparely populated, everyone drives down the middle of this road and moves over when necessary. My now sold HHR Panel, the Cats started Stinking after 40k miles or so, disgusting smell !! Sold it at 85k miles. Several of my friends cars had the same issue. Our newer Dodge 4WD pickup, doesn't smell like the typical diesel exhaust,, more like Hot Horse Piss, seriously... It seems like there's always ONE Car in front of me on a highway that stinks.

As far as emissions and Cat'less exhaust, here's my knowledge based on my Cars.

My '56 Chevy LS1 & Tremic T-56, No Cats, No Does not Stink ,,,, 2007 BBK Shorty rear dump Tuned Headers, Full 2 1/2 inch exhaust with cross over, power tuned, front Oxy sensors only. A blast to drive now with the tubular front control arms with rear steer rack in all these corners out here. Good sound when driving , loud when ..... One of the great things re this old Gal, only ONE Computer.

My old C4 Convert, since 2000 updates. also No Cats, all three gone. Passed the Sniffer Test. No Does not Stink. Fast Burn ZZ4 SBC w/hot cam, fast 4 wire Ozy sensor , S/S shorty headers, Borla Exhaust, Larger Throttle Body & Injectors, power tuned three times, to get it to run properly. Also had New Doug Nash and 3:73 gears installed when we installed the new ZZ4 . Rides like a Go Cart, such fun. Plans, upgrade the ECM to 2008 C6. I have exp with this year ECM and the wiring.

My '98 C5 Covert, stock LS1 & 6 speed, No Cats, No she does not Stink. Borla exhaust w X. I need to re-pin the ECM connectors and replace the ECM to the 2001 up with a power tune. She has an occasional pop out the exhaust when slightly accelerating after going down a slope with foot of the throttle PITA. Great Driver, Leaving this one pretty much alone.

Sons 2004 ZO6 Le Mans FRC, 34k miles, all original except power tune and Nitto NT01 tires. Still has the Cats, but doesn't stink,, yet anyways.

I'm currently building a '37 Chevy Coupe frame up build. Def No Cats, New LS3 w dual mirror image turbos, front fender exhaust exit, Super Mag Tremic T-56, C4 suspension front and rear but with Dutchman's IRS 9 inch Diffy Housing, C6 brakes, steering column and Instrument Panel. Stink, prob not, but I don't care. She will be too Loud for anyone to Notice....

From my experience, if any mods are completed,,,, like cam kit, exhaust, Cats (remove or upgrade), throttle body, Diffy gear ratio, injectors, and the like. The ECM will need to be updated too !! Power Tuned, if one is making such changes. The slightest changes make dramatic changes in a OEM tune...

Michael...





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The emissions test is not a sniffer on OBD2 (1997+) vehicles (unless it has changed very recently). Technically, to be legal you need catalysts. That being said, since they only hook up to the ECU as long as you show no more than 1 "not ready" monitors on 2001+ year models it will pass. You may need to put something there to pass visual inspection, but most places won't do this, and if they do you can just put something there to look like a cat.

https://www.dps.texas.gov/rsd/vi/con...ionTesting.htm