Have an 01' f-150 143,000 mi. with dual exhaust. I want to replace the cats and the exhaust. The mechanic that does stuff on my truck that I can't do was going to replace an O2 sensor and he did but he said it didn't make any difference because my cats were running hot. So now I'm thinking I'm just gonna replace the whole nine yards now since I have exhaust leaks and its all rusted out. Anyone have any insight on anything. Should I redo headers or leave them? Can I eliminate some cats? I would like to gain some HP if I could. HELP PLEASE. Also my low end power is missing hopefully that is due to the exhaust

 

If you want more HP and need to replace the cats anyways I would just suggest taking them off and putting straight pipes in. I'm in the same situation, my passenger side cat recently failed and instead of spending the money to buy a new one I'm just going with pipes, much much cheaper and from what I've heard gives you quite a noticeable gain in HP and noise level.

As far as heads go I don't know much about them as far as how much power can be gained with them or cost or anything, so I don't know what to suggest to you there.

 

You can just eliminate the cats? What about the O2 sensors down there. I know there are two of them. Won't that trigger a CEL light?

 

I'm not too sure about that, you'd think that it would throw a code but from reading around on here it sounds like several guys have done it with no code by cutting after the first 02 and I guess before the second. Like I said I haven't done it yet, I'm waiting to get all moved back into school in a couple weeks then I'll get it done.

Give the thread a few days and maybe some guys that have done it will chime in, since I'm also curious to hear more about that... of course I don't care much cuz places that will pass you for a few extra bucks are a dime a dozen around the performance shops a few miles from my house lol but if nobody posts anything for awhile I'll definitely let you know how mine goes when I take them out.

 

Thanks chili that would be cool

 

There are after market high flow cats you can use. As far as cutting the cats off, if you live in a state that requeires inspecxtion or smog test it will never pass. Summit racing offers a pretty good selection of after market headers including shortys that bolt right into place of your old manifolds. They come with hardware and gaskets. They claim to get like 15-20 HP. I was looking at them for my 01' 5.4L.

 

no inspections here in Minnesota, so I don't have to worry about that

 

no it will not throw a code just remove the back 2 cats (the bigger of the 4) and ad strait pipes. the small cats are just pre cats anyway and dont do a lot. it was the best thing i ever did to my truck!

 

So if the code comes up is there a way to get rid of it.

 

if it does just disconnect your battery for ten mins and it will go away. but i have had the cats removed for 5 months now with no c.e.l. or problems.