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Lowest emission Downpipe ?

UNtamed67

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Currently I have a Catted Mishimoto downpipe. The pipe broke off twice from the holders and had to be let 2 times. Last year I had to pass a technical control (after 4 years mandatory in Belgium) and I didn't pass with the Mishi, emissions were too high !! Had to switch back to default downpipe to pass the check. In august I will have to do the same exercise. As I can't do it myself it costs me $$ at every swap and it seems the connection with the Turbo is not made to be opened up many times.

To avoid all this hassle I'm looking for the lowest emission but good performance catted downpipe able to pass the technical tests. Car has a stage 2 tune.

No brand seems to mention the emission rate so it's like a gamble... advise is more than welcome !
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Jaymar

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I live in an area that uses the more stringent California emission standards so I was interested in getting the best shot at passing the first time. I haven't put mine on yet so I can't actually speak to results but I got the MAP downpipe with the GESI converter. They use a higher quality cat with a higher cell density than your average aftermarket unit. The only drawback is that this is also reflected in the cost. Hopefully somebody else here has tried it as well and can verify the results. It isn't CARB compliant so it won't pass a visual inspection but nothing in the emissions system other than OEM is.
 

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UNtamed67

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Chef jpd

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It pulls the O2 sensor out of the exhaust stream and it then reads lower oxygen levels.
high flow cats produce levels that will either throw a CEL, or show.sensor not ready.
 

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Jaymar

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The second O2 sensor measures the effectiveness of the catalytic converter and basically verifies that there is still a functional cat in the system. This sensor needs to be in and see normal parameters to read as ready on the plug-in smog check. Aftermarket cats are generally less effective and may not trip the threshold that the second O2 sensor needs to see to keep the system happy. Like John said above, pulling the O2 sensor out of the stream lowers the amount of hydrocarbons seen so it pushes the second O2 sensor over the threshold to be happy.
 
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UNtamed67

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The second O2 sensor measures the effectiveness of the catalytic converter and basically verifies that there is still a functional cat in the system. This sensor needs to be in and see normal parameters to read as ready on the plug-in smog check. Aftermarket cats are generally less effective and may not trip the threshold that the second O2 sensor needs to see to keep the system happy. Like John said above, pulling the O2 sensor out of the stream lowers the amount of hydrocarbons seen so it pushes the second O2 sensor over the threshold to be happy.
I suppose this is only for data reading and triggering, in fact at this tech control they put a kind of pipe in the exhaust and they use a machine to analyze the generated fumes. Any way to trigger these figures? Guess an extender will not help ?
 

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I suppose this is only for data reading and triggering, in fact at this tech control they put a kind of pipe in the exhaust and they use a machine to analyze the generated fumes. Any way to trigger these figures? Guess an extender will not help ?
Yes, that is correct. If they do a sniff test with the probe in the exhaust you will have to rely on an effective cat to do the job. Usually the spec for the test is loose enough to accommodate older vehicles wear and tear and possibly cat repairs with aftermarket cats but that is entirely different for every locale.
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