Exhaust question

[turbo]

When I get a new exhaust on my 1.4T I'm planning with a full turbo back exhaust from ZZP with no primary cat. I am going to go with the high flow secondary cat. What I'm wondering...do any of you know how effectively the secondary cat filters out carbon monoxide? I imagine it won't do it as effectively as the big primary cat, but I'm wondering if it still removes some...

 

[sx sonic]

I don't think anyone can accurately awnser that as I've not heard any one post what that catylyst filters or its effeciency.

Assuming it is made from the same material as the 1st cat it will reduce NOx, CO, & HC emmissions.... to a lesser degree than the 1st cat, this is due to several reasons.

1. It is farther from a heat source which reduces catalyst effeciency and

2. It has a smaller cross section than the 1st cat reducing its effectiveness.


I'm running a catlees downpipe and then stock exhuast until the second cat, at which point my exhuast ends.

At start up there is a detectable increase in emmissions (smell), same for at WOT

 

[Eric Smit]

it will remove some, but likely not enough to pass emissions.

 

[dvn]

I am running ZZP DP, Mid-Pipe and high flow cat. I can tell you this, you can see light through the material in the cat and it does stink.