rear catalyst obstructed what my options?

alecsey · Postby **alecsey** » Sat Apr 25, 2015 6:53 am

Hi I wanted to get an advice from someone who had similar problem.

My bay 1 (passenger side) upstream 3-way catalyst broke up inside and chunks of catalytic substrate went into the downstream catalyst (they call it front exhaust tube I think). I was able to shake out of the downstream catalyst all of the loose chunks and debris, but I think air flow is still quite obstructed. The substrate in the downstream catalyst must have been clogged. While the air goes through brand new catalyst with ease, I tried to blow through my downstream catalyst and while the air went through I had to make an effort.

My question is what my options are at this point? Can I continue using somewhat clogged downstream catalyst? Should I replace it? What are other options? Can I hollow it out without affecting ECM, A/F control (there are no sensors behind it)?

Thank you!

Postby **disallow** » Sat Apr 25, 2015 2:19 pm

The secondary cats are not monitored, therefore you could chop then out or hollow them with no lights on the dash. But would probably change back pressure and exhaust note some.

alecsey · Postby **alecsey** » Sat Apr 25, 2015 4:39 pm

Thanks for your comment. I am wondering if this change in back pressure somehow can be adjusted in the system. Or the system could learn it by itself?

disallow wrote:The secondary cats are not monitored, therefore you could chop then out or hollow them with no lights on the dash. But would probably change back pressure and exhaust note some.

Postby **smj999smj** » Sat Apr 25, 2015 8:50 pm

If you gut it, it's decrease in backpressure will help performance, if it does anything to it at all (other than change the tone of your exhaust). The ECM is constantly self-learning and making adjustments.

alecsey · Postby **alecsey** » Sun Apr 26, 2015 2:39 pm

Thanks smj999smj for your comment. I was wondering if it would be better to gut both rear cats to equalize both sides so to speak, or it does not matter?

smj999smj wrote:If you gut it, it's decrease in backpressure will help performance, if it does anything to it at all (other than change the tone of your exhaust). The ECM is constantly self-learning and making adjustments.

Postby **smj999smj** » Sun Apr 26, 2015 4:45 pm

I would do both, if you are going that route.

alecsey · Postby **alecsey** » Wed Apr 29, 2015 11:03 pm

smj999smj wrote:I would do both, if you are going that route.

OK cool thanks for your comment. I think I would like to go that route especially that I may give an opportunity to take a look at the condition of the other driver side front catalytic converter.

rear catalyst obstructed what my options?

rear catalyst obstructed what my options?

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