Catalytic Coverter Question - Honda Prelude Forum

squeaky0032 · 11-23-2011, 10:27 AM

Hey guys, my CEL just came on yesterday, P0420, for the catalytic conveter.

If I remove the cat, will it cause damage to the motor?

(what i intend to do, is remove it, break the filters out, and reinstall it, making it a "free flow" cat)

Will it damage the motor at all, and will I notice an increase in Horsepower, and/or decrease in gas mileage?

2nd Prelude owned, and love them to death. But just starting the construction on this one.

P.S. Yes, i know the laws for emissions, and i live in Florida where there is no inspection. So I am not worried about that at all.

Nighthawk01 · 11-23-2011, 10:42 AM

Removing the cat will not help you get rid of a CEL.

Making it a free-flow will not give you any gains on a dd. You may see some gains using it on a track but the difference is so small it's not worth the trouble.

You may have a bad secondary o2 sensor vs a bad cat. You can possibly still clean the cat - i believe there is a writeup floating around saying you can bleach it? Not sure how well it works....

If anything you'll notice a decrease in fuel economy because your o2 sensor will be reading incorrectly so the ecu will be trying to correct this. There is a bypass available though - again not too sure how well that one works.

squeaky0032 · 11-23-2011, 10:50 AM

well, the thing about it is, I dont have the money to replace the CAT, and I know it wont fix the CEL, I just dont wanna get caught up in too much back pressure.

Besides, its a simple 30 minute job.

Where can i search to find the bypass for the o2 sensor?

Rycon · 11-23-2011, 02:30 PM

Quote:

Originally Posted by squeaky0032

I just dont wanna get caught up in too much back pressure.

Stop thinking that way.

Advanced Exhaust Tech I - Team Integra Forums - Team Integra

Advanced Exhaust Tech II : Backpressure and Area - Team Integra Forums - Team Integra

usmcmarc · 11-23-2011, 06:24 PM

You can get a Magnaflow Universal CAT for around $100.

minilogoguy18 · 11-23-2011, 08:18 PM

You should only be hallowing out the cat if it's clogged causing the car to run like **** and overheat. The CEL is more than likely for the secondary O2 sensor and not the cat.

Kronn 98SH · 11-24-2011, 05:42 AM

Quote:

Originally Posted by minilogoguy18

You should only be hallowing out the cat if it's clogged causing the car to run like **** and overheat. The CEL is more than likely for the secondary O2 sensor and not the cat.

Disagree ^

9 times out of 10, p0420 = bad cat. Do the proper trouble-shooting and find out.

Quote:

Originally Posted by usmcmarc

You can get a Magnaflow Universal CAT for around $100.

You can get them as low as $50.

squeaky0032 · 11-26-2011, 07:07 AM

Well, having looked under the car, and trying to consider gutting the cat... Found out, IT wasn't there!

They had straight piped it.

So now, i must find a way to bypass the o2 sensor to get that CEL off my car!

any ideas?? or references?

Kronn 98SH · 11-26-2011, 08:02 AM

O2 Simulator, E-commerce