Catalytic converter Help

[talonz27]

Here is my prob, i have straight thru 3in exhaust with no cat (just a magnaflow muffler #14834). and both my o2 sensors are bad so i bought 2 new ones and before i put them on i want to decide if i should get a hi flow cat on my car. I hear that replacing the rear o2 sensor is pointless if you have no cat because it will ruin it. but will i lose or gain any power with installing a hi flow cat i hear a lot of argument on both ends? here is the one i would buy if i decide to go with a cat.

eBay Motors: 59959 Magnaflow Metallic Catalytic Cat Converter 3" (item 140192153035 end time Dec-28-07 05:41:15 PST)

 

[synthetek]

Performance should be better without the cat, I would not install one unless its required by your state for smog. If you want to run without the cat and not get a CEL or burn up the sensor you can use one of the mechanical or electronic fixes for the rear o2.

Rear O2 Sensor mechanical fix for CEL code P0420 - ScoobyMods

 

[Artago]

Here is my prob, i have straight thru 3in exhaust with no cat (just a magnaflow muffler #14834). and both my o2 sensors are bad so i bought 2 new ones and before i put them on i want to decide if i should get a hi flow cat on my car. I hear that replacing the rear o2 sensor is pointless if you have no cat because it will ruin it. but will i lose or gain any power with installing a hi flow cat i hear a lot of argument on both ends? here is the one i would buy if i decide to go with a cat.

eBay Motors: 59959 Magnaflow Metallic Catalytic Cat Converter 3" (item 140192153035 end time Dec-28-07 05:41:15 PST)

Will this cat fit? I have a OBX Hi Flow. It fits but I have a rear O2 code and the cat and sensors are brand new.

 

[synthetek]

Will this cat fit? I have a OBX Hi Flow. It fits but I have a rear O2 code and the cat and sensors are brand new.

Its not a bolt on, if you have a 3' exhaust it would work but flanges would have to be welded on to make it fit, you would be better off using one of the methods in the link I posted above to just eliminate the CEL.

 

[talonz27]

its just a universal fit meaning i would have to weld it on. Your not going to find a bolt on converter once you start putting the nice and big downpipes and catbacks on your car that dont come with a cat on them. im not really interested in the whole eliminate the rear o2 sensor. i just wanted to know how my car will take to a high flow cat power wise.

 

[Artago]

Yeah the OBX I got required me to weld on flanges. I got the flanges from ExtremePSI. My question is about the Cat itself. It looks big and round.... Will it fit under the car? (assuming I weld on the flanges like I did with my OBX cat).

 

[synthetek]

RRE makes a bolt on 3" cat but if your system dose not have a place for a cat yes it would have to be welded in, I have that and the RRE 3" test pipe so I can switch them out when I go to the track & stuff, my performance is better without the cat. I have DSMlink so I don't have to worry about the rear o2 CEL . The function of the rear o2 sensor dose not affect the performance of your car its just there to verify that the cat is working. With an aftermarket high flow cat you could still get a CEL so should still consider some other methods of avoiding it.

 

[Artago]

^^^ I've heard this before. So the rear O2 and rear O2 cel has no effect on the performance, fuel trim, or timing of the car what-so-ever? It's there simply to check the efficiency of the cat? If so then great, I can ignore my rear O2 cel code? Thanks.

 

[synthetek]

^^^ I've heard this before. So the rear O2 and rear O2 cel has no effect on the performance, fuel trim, or timing of the car what-so-ever? It's there simply to check the efficiency of the cat? If so then great, I can ignore my rear O2 cel code? Thanks.

Yes that is correct if you don't mind the CEL you can just ignore it but you will need to check with an OBDII tester sometimes to make sure you don't have any other CEls. Here in California we cant pass oor emissions test if we have any CELs on so we have a working cat for emissions tests or eliminate the CEL by other methods.

 

[Artago]

Yes that is correct if you don't mind the CEL you can just ignore it but you will need to check with an OBDII tester sometimes to make sure you don't have any other CEls. Here in California we cant pass oor emissions test if we have any CELs on so we have a working cat for emissions tests or eliminate the CEL by other methods.

Great. Thanks for the advice.

 

[mitch26753]

the only way i would worry about getting a cat is if you live in a state where you have yearly inspections...here in wv we do and its a pain in the ass to get your car inspected unless you know someone that will let you pass

 

[Artago]

the only way i would worry about getting a cat is if you live in a state where you have yearly inspections...here in wv we do and its a pain in the ass to get your car inspected unless you know someone that will let you pass

Same here.

 

[Colossus1984]

Performance should be better without the cat, I would not install one unless its required by your state for smog. If you want to run without the cat and not get a CEL or burn up the sensor you can use one of the mechanical or electronic fixes for the rear o2.

Rear O2 Sensor mechanical fix for CEL code P0420 - ScoobyMods

How do I know if the problem I am having is my CAT?

 

[Artago]

How do I know if the problem I am having is my CAT?

You can get it tested but the test costs as much as a new cat.

If you're car is running rich then it's most likely dead. If it's more than 10 years of it's definitely not working at 100% efficiency.

Tom

 

[gorf]

my 2 cents

I bought a 3 inch megan downpipe and this cat :
3.0" Catalytic Converter High Flow Universal DynoProven - cut and paste and search on it on Ebay.

In my state they do a visual inspection to make sure that you have a cat. This one believe me does not slow down the exhaust very much, if you hold one end up to the light you can see right through it!

I had to cut the pipe and weld it in - a little more work but no big deal. I installed the downpipe, held the cat in place and marked the dowpipe for cutting. I pulled the downpipe and cut it leaving about an extra 2 inches on both sides. I then reinstalled the downpipe, slipped the cat in place and bolted the rear flange. then took some 3 inch muffler clamps and clamped the cat in place, Pulled it and welded it. Fit perfect, sounds great, passed inspection and I am doing my part for environment

 

[Colossus1984]

You can get it tested but the test costs as much as a new cat.

If you're car is running rich then it's most likely dead. If it's more than 10 years of it's definitely not working at 100% efficiency.

Tom

My car is a 1984 Ford Exp and I have only had it for about 4 months. I am sure the CAT is not new.

 

[1g dsm d22]

i have a magnaflow cat, and im thinking about going to a better real high flow cat. but that will be later.

 

[Artago]

my 2 cents

I bought a 3 inch megan downpipe and this cat :
3.0" Catalytic Converter High Flow Universal DynoProven - cut and paste and search on it on Ebay.

In my state they do a visual inspection to make sure that you have a cat. This one believe me does not slow down the exhaust very much, if you hold one end up to the light you can see right through it!

I had to cut the pipe and weld it in - a little more work but no big deal. I installed the downpipe, held the cat in place and marked the dowpipe for cutting. I pulled the downpipe and cut it leaving about an extra 2 inches on both sides. I then reinstalled the downpipe, slipped the cat in place and bolted the rear flange. then took some 3 inch muffler clamps and clamped the cat in place, Pulled it and welded it. Fit perfect, sounds great, passed inspection and I am doing my part for environment

I did the same thing except I welded flanges on the down pipe and cat so I could swap it out. I have 2 CATS, OBX and Magnaflow. OBX flows better so I run that daily, and the magnaflow cleans better so I swap that it for emissions tests.

Tom