3rd Gen Catalytic Convertor

[NudgE^SIKBRO]

Hey guys, just wondering has anybody removed the secondary Cat from the exhaust of your 4.6 explorer? The big cat. Did it have any good or bad gains mileage, engine codes, exhaust note and so on? My cat is stuffed and im thinking about getting rid of it all together but before I do I want to know if its worth it...

Cheers Dan

 

[Styx]

I'm sure there is someone on here that I read about that removed all 3 cat's from his 4.6 ex and loved it... He just hollowed them out with a piece of rebar or something???...
Do you have emissions testing down under???
One thing you will have a check engine light on after you remove any of them for cat efficiency low...

 

[mendy]

By big cat, you mean the big muffler or are you smuggling zoo animals?

If you want to remove it then go ahead, but get it flanged with a straight peice of pipe, so if it sounds poo you can bolt something back in

I got a 2 1/2 inch with new muffler and cats, acceleration was better but no huge power gain or anything like that. Its a heavy car so fuel usuage will always suck

 

[Limited02]

Getting rid of the 3rd cat will not be an issue and no lights/codes will get thrown. Getting rid of all the first two cats will and will require a tune to have the 02 sensors turned off.

I removed my 3rd cat and had 2.5" exhaust run through a Flowmaster 70 series muffler. I think it helped a little, but nothing that will knock your socks off. I love the way it sounds, not too loud, but enough to let you know you've got a V8 underneath.

Here is an old video. I really need to make a new one...

 

[HiImBrian]

I'm sure there is someone on here that I read about that removed all 3 cat's from his 4.6 ex and loved it... He just hollowed them out with a piece of rebar or something???... Do you have emissions testing down under??? One thing you will have a check engine light on after you remove any of them for cat efficiency low...

Yup that someone was me. I pulled the y pipe and used a piece of threaded rod I had laying around and a hammer. Sounds great and runs fine. No emissions here in Florida but I am throwing O2, PCV and EGR codes. Now, I removed the PCV and EGR components so that is to be expected. However they can all be removed with a tune.

 

[blue_goose]

Mine's a 4.0 but I was in the same boat. I didn't want to mess with the computers so I had new pre cats welded in (best $100 I spent- very tight space) and I cut the secondary cat out and welded in a pipe. Exhaust is louder and sounds better but its not a huge difference. I think I may have gained .5 mpg on the highway. Gains aren't huge and if you ever have to smog it your screwed but the secondary cat is a easy thing to do with basic welding skills and worth it if you don't care about being a earth thug.