Does the Evo 9's stock cat gets clogged? How many miles does the stock cat good for? I feel like the back pressure is building and it wont let the exhaust out, holding the car performance. Have anyone tried de-clogging their stock cat? Is that even possible? How did you do it? Thanks for the ideas

 

Only way to unclog a catalytic converter is a steel rod right through the middle.

A regular muffler shop should be able to replace it no problem. Another idea is hit up the used FS section for a high flow cat for around $100-150 if you get lucky.

 

factory cat should last 100k miles at least, if you feel its clogged unbolt it from the downpipe and see how the car runs then

 

My cat decided to go bad a while back, didn't know it was bad until I found my answer on here. I got a rotten egg smell from my exhaust when this happened

 

why dont you get a high flow cat? or test pipe? i have the UR HFC and it flows well and keeps noise to almost same as stock cat.

 

Thanks for the feedback. Another reason I ask was when everytime I clean my car, I always notice at the end of the tailpipe. I usually wipe and clean it up to show the shinny metal underneat it. I plan to stick with the OEM CAT to get off the trouble of installing and removing test pipe every 2 yrs for inspection. As for HFC, I do have a Helix but I got it used and I am not sure if installing it will throw a code plus I have to move the O2 sensor...

 

It is very unlikely that the stock cat would have begun to breakdown unless you have some unusual materials passing through the exhaust. (metal from the turbo impeller for example). If you have done some work recently on the exhaust, then debris could have entered the downpipe and gotten into the cat.

Or the other possibility is running a fuel air ratio biased towards too much fuel can possibly overheat the cat and cause it to breakdown.

Otherwise it would probably only happen if your drive takes you along an old never maintained gravel path that constant tosses softball size rocks against the cat.

Soot or whatever you call it, on the rear facia around the tailpipe is normal for these cars in stock form.

Some brainstorming on your perceived power losses here:
Are you getting a boost leak? (Throttle body seals, old intake hoses, damaged intercooler, valve seals, etc)

Knock sensor is holding things back? In my case the knock sensor mistook vibrations due to worn out cold engine mounts as knock and retarded the timing and I think it can also command the boost controller to minimize boost as well. It would start trying to save the motor as I passed 5000-6000rpm on cold days.

 

Switch from my stock cat to an ur hfc ceramic picked up 15hp/12tq.

 

Interestingly enough, I recently received a letter from MMNA. Its subject matter is Customer Satisfaction Campaign SC-13-002. Its for 2006 Lancer Evolution. MMNA is recommending a product improvement for my 2006 Lancer Evolution.
The Recommended Product Improvement : The current software programming for the ECM can allow for high catalyst temperatures that could cause damage to the catalytic convertor if the vehicle is operated in a continuous, over-redline manner. The updated software programming will have the vehicle exhibit a much more pronounced fuel cut or power reduction (~200 RPM) if operated in the over-redline fuel cut out range for several seconds. This will provide further notice to the driver to upshift or reduce throttle input.
If I decided to have the dealer update the ECM with the updated software programming, MMNA authorized dealer will extend the cat warranty for 1 more year (2014) or until 100k miles whichever is longer. And they will also give me $50 fuel card.
I just wanted to share this information to all 2006 Lancer Evolution owner who has not tuned their cars yet, I mean has remained stock all these years
So to all Evo owner - any advice on taking advantage of this Product Improvement? I am thinking they will further reduce power on my puny stock 2006 lancer evolution...FWIW...thanks again for your input...cheers!

 

Mitsubishi says it's tune is causing the stock cat on the 9 to overheat.

 

Haha yeah I got that letter too. It went into the garbage can.