I have done a search on this already but im not finding the answers that im looking for. I took my car to two different repair shops and they both told me the cat is clogged. I want to do a test pipe but first off i live in Washington where we have emissions so what are my options as far as the front o2 sensor goes? Also from what i have heard is that the cat is tied into the exhaust manifold somehow? I have the 1.8 T. Any help with this would be greatly appreciated. I dont want to pay the $600 the repair shops want to replace the cat when i can pay less money for better performance.

 

Labree HFC. Your car bolts to your turbo which bolts to your mani.

 

Labree HFC? So let me get this straight......from the rear the pipe goes to the cat, which bolts to the turbo, which then bolts to the exhaust manifold? How hard is it to remove the cat my self?

 

Contact a company in cali called Labree and ask for a 200 or 300 cell high flow cat. It will give you the same performance gain as a test pipe, which is minimal anyway, but won't throw CELs and will pass emissions. Changing it out isn't too hard

 

You could run a test pipe and o2 spacer as well

 

what about on a non turbo 2.8L? could you run at TP or is it going to trip the cel?

 

A testpipe can be run on any set up, as a testpipe is simply an empty pipe in place of a catalytic converter. They are more common on turbo applications though because less resistance behind the turbo is better. Power gains may not be as significant on a naturally aspirated car. A test pipe by itself will trip a CEL because the O2 sensors will report that the exhaust is nasty. You can choose to run an 02 spacer or some even weld in an o2 bung with a bend. These work because they space the sensor tip from the main flow of nasty exhaust, thereby causing it to read less nasty stuff.

The spacer is made by stacking two spark plug spacers onto each other, one thats been drilled out, and then plugging that into the o2 sensor bung and putting the sensor in after that. Search around for a write up.

Finally, like Faster said a High Flow Catalytic Converter will net you similar power gains. A high flow cat is truly the best option as it combines the power gains with legality. The cat still neutralizes exhaust gases, and it will pass through emissions, where as even a test pipe with spacers may fail a visual inspection or a tail pipe sniffer. Trust me, I had a test pipe but I put on a Techtonics High Flow Cat.

 

Kayak is pretty dead on there. Even I run a 4" cat in my 3" downpipe. I can't remember exactly but I think its 100 or 150 cell. The only restriction I have is I can't run race gas. But hey, >500awhp and passing emissions FTW

 

i run a test pipe, with no spacers and no cel for me, although i wont pass emissions im lucky where i live there isnt any.

 

Awesome! Thanks for the help everyone thats exactly what i was looking for. How much for the cat from labree? Ill try to get a hold of them tomorrow. And how hard is it to do the cat myself? Is it just bolts or? The repair shop said its a pain because its tied into the exhaust manifold? Thanks again!