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Does exhaust modification mess with emissons testing?

1K views 9 replies 8 participants last post by  Dusty 
#1 ·
Hey there!

I have read a lot lately about exhaust modifications. I would like to do some modifications myself but I don't won't to deal with emissions issues. Can someone tell me what I can do? I live in North Carolina.
Am I too paranoid on this issue? Maybe exhaust mods won't interfere with emissions?

Can someone please enlighten me?
Thanks in advance!
 
#2 ·
It depends on the mods, BlueT-Bird.

TECHNICALLY, if you alter the exhaust ANY, it voids the emissions standards.

But TECHNICALLY, if you change your spark plugs, it voids the standards. PRACTICALLY, any inspector who fails you on that is ... well, let's just say he's VERY male and VERY fecal :diablo:

The secret is to keep the cats running and to verify that you use good cats.

Ideally, you'd order the Mandrel Exhaust Systems system, both halfs, and run those.

Also, be sure to replace the O2s if you haven't done that yet.

RwP
 
#3 ·
I can't say specifically regarding NC standards, but generally if you leave everything from the exhaust manifolds back to rear-most thing such as O2 sensors or resonator/converter you'll be fine. That means you're really only changing the tubing or mufflers from where it joins at the "Y" point.

What specifically do you want to do?
 
#5 ·
Technically speaking, any exhaust alteration from the cats forward violates federal law.

Emissions testing is fairly easy to get by. A lot of areas simply use scanners on the OBD II port and check for codes. No sniffer or nothing. A car deleted cats and a tune with the rear O2s shut off can pass that kind of test. If you have inspections though, you'll have a tougher time as it's really up to the discretion of the inspector to overlook an alteration. Deleted cats definitely won't get past inspection.
 
#6 ·
If I was in an area that did "visual inspections" of cats when I didn't have any, I'd have some fake ones on there!
 
#7 ·
depends on the type of cats and if you had new o2 put on. I have seen a lot of after market and custom set ups done that has passed testings before I moved down to fl. the tester did check for the cats and did the sniff test with the tester. they passed with flying aces as long as you have all of the emmissions still on the car you will still pass
 
#8 ·
Back when I lived in Raleigh NC they were strict. Visual and a sniff test with a printed output including engine RPMs with the sniffer readings. Better to ask RobertP.

Got to love Florida and Alabama - cats? Mine have 4 legs and furry.:)
 
#9 ·
here in Mooresville, nc im running no cats with a tune. the tune disable the rear O2 sensors and I don't have any problem with emission at all. as long as I don't have any check engine lights I pass
 
#10 ·
I was curious so I looked into it. Things have improved. I could even pass.

Depends on what county, but if you are in an emissions county only an OBD check on 96 and newer. Older, no check. Got to love progress. No more PIA sniffer test like Wake county used to have in the 80's,
 
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