I have an 02 FX4 anyone ever remove the stock cats and replace with highflo Cats? IS this legal to do? Im looking at the possibility of replacing the Cats with Maganflo Cats. Any help on this matter would be great.

 

as long as you are installing new cats, it should be legal. Check local laws if you want to definetly be sure though.

 

i live in Jersey so Im gonna go to the local muffler shop and inquire if I can use the 2 or if I need the 4 of them. Thanks

 

You can get rid of your 4 factory ones and replace them with 2 hi-flows.

 

There's no reason to do this. It won't help you any, or at least I couldn't tell a difference with no cats.

 

just figure i would tinker, the precats sound like theres marbles in them wondering if i should change the setup to high flos

 

are you kidding?? he wants to replace his 4 cats with 2 hi flow cats. not completly take them out. and yes it will help. im going to do that to mine in a month or so. it will also make it slightly louder.

 

That's the way to go. I am very happy with my Hi Flow cats from Magnaflow. I changed them because I had a good excuse ( and legal ), my truck was over 100K miles at the time.

 

Maybe this has been said before, but here it goes. How much can I expect to pay for two hi-flow magnaflow cats? I can't remember, do you face issues with the 02 sensors? I thought that there were4 of them, one on each cat.

 

there is an o2 sensor before the cats and one after the cats (on each side). So a total of 4 02 sensors. Remove the 4 stock cats and replace with 2 hi-flow and leave the o2 sensors how they are, unless you feel like replacing those too.

 

There are 4 sensors not because there are 4 cats. There are 4 sensors because the 2 upstream sensors need to check what's coming out of the engine and the 2 downstream sensors will check what's coming out of the cats. So when doing the 4 for 2 cat change you better leave the sensors where they are.

In my case I changed the two upstreams because one came damaged after the visit to the shop for the cats installation. They were very old so I purchased them. I will be doing the downstreams very soon.

 

on my truck there are 2 sensors in front of the precats and 2 on the second cats. magnaflow makes some cats that have the threaded holes for 02 senors already on the cat. my plans are to cut everything behind the first set of sensors, add pipe and put in 2 magnaflow cats.

 

THanks JmTruck and SngStr. So, if I put in two hi-flow magnaflow cats that come with threaded holes and leave the other two sensors that are after the cats alone I should be fine? No engine codes thrown. do they make ones that are specific to these trucks or are they universal (as far as the threaded o2 sensor holes are concerned)?

 

Right now I forgot the part #. If you go to their website and do the search you will find the specific cat with no air tube, no threaded holes, 2.5" in and 2.5" out and all SS. At least those are the specs for mine, a 1998 5.4. I hope this helps.

 

Check this out. http://www.troyerperformance.com/cgi...c%20Converters