Long headers and failed emissions

Bullitt347 said:

Long tube headers will not affect catalytic converter operation, once the exhaust system is up to temperature.
The reason all manufacturers place the catalyst as close to the cylinder head as possible is to get the catalyst to "light off" as soon as possible to decrease emissions as soon as possible. Long tube cats, just delay that operation. It is possible that if the car just sat an idled for a long period of time, that the catalyst could cool off and not perform it's function. If sitting in line at an emissions test station, and you are going to be in line for more than 5 min, just hold the idle speed up to about 1,500 rpm and that should be sufficient in keeping the catalyst operating correctly.
The only downside to long tubes and catalytic converters concerning emissions testing would possibly be from a visual inspection, if your State has visual inspections.

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Methodical said:

As long as you have the converters on you should be ok for visual inspections. They are looking for the converters, unless your state specifically ban long tube heagers. Check your state law. I know a gentleman who had long tube headers and he passed inspection here in Maryland. From what I recall, the converters are in the same location and the only difference between LT and ST headers were the mid pipes length. It's been long time since messing with those...going off memory.

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Mindseye007 said:

What h-pipe are you running?
I have longtubes with a Mac h pipe I was told just to get the car warmed take it for a good run get everything warmed up just before the test and I passed with flying colors.

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