Ok guys.....im in need for help....looked in this forum up and down only to get confused. ALOT....lol. I have an 05 FX4 5.4 it has 4 cats on it and there shot to hell....i see in all the posts here about high flow magnaflow ones with part number #94106.. But i looked it up and the cat is straight not bent on an angle like the ones on my truck?????? The cats closest to the engine are the ones i must replace and they have the angel built in to them. Is there a differnt part number forthem???? Or can someone please sent me in a direction to a replacement high flow that will work....Also if i cut the other 2 cats out will it trip an engine code???? I want to do this one time and do it rite, im not well off so my cash is very important to be used lightly hahah...thanks guys in advance. I hope someone can help me out....

 

the curved cats closer to the manifolds are the pre cats. most people leave those in and cut the rear cats(the ones behind the pre's) out. or cut out all 4 cats and put in two hi flows. if you cut out the rear cats you shouldn't throw a code if you do it right. just be sure not to cut the o2 sensors out

 

Thanks for the reply Red!!!!! So could i use the part number i have in my post? So i guess i need o2 sensor bungs??? Where might i find thoes??sorry for all the newbie questions but i have nobody else that will help me...my truck has been broken for over a year and hasnt seen over 3500 rpms .....i want my truck back to normal already!!!!

 

i would think a muffler shop would have bungs? but idk honestly lol

 

I cut out the second cats on my 97 and welded in pipes without cutting out the bungs. I havent tried it on my 04 yet but it looks like you can. If you have to replace the bungs the O2 sensors are the same size and thread pitch as a large spark plug. You can use the "anti foul" adapters to back the sensor out of the exhaust stream to fool the rear O2 sensor if you do throw a code for being too rich.

The nice thing is if you recycle your old cats you can sometimes get more than the Manaflows cost. The Hi flow cats dont have all the precious minerals that the factory cats do.

If you need a measurment for the bung I can get that tomorrow. Too busy drinking right now.

But like stated above if you leave the precats(the curved ones) you usually dont throw a code just using straight pipe.<---This is the part where some posts that its illegal to remove cats..

 

Thanks Jug! So the precats dont get clogged? Just the second set? I was going to try and have a shop do the exhaust for me and cut the first set out and use the magnaflows and leave out the second set all together. Was going to weld in the o2s after the first set alittle behind the cat.....but if i can just cut the second ones out and the pre cats arent clogged i could go that rout...

 

I cant say yor pre cats arent clogged, The ideal route is to have some magnaflow cats welded in and all 4 stock cats removed.(just make sure you take them to recycle$$) If you have the means cut out the seconds and wel d in the straight pipes. Very cheap and might solve your problem, and gives a pretty good sound.

If all four are bad you would benefit more from going the extra mile and gettin the high flows

 

First off... why are you're cats "shot to hell"? Usually there is a reason it happens. I'm not being a smartass, but you may have an underlying issue - you might have to replace them again if this is the case.

 

I had an issue with the throttlebody and 5 and 6 coil pack. I think it dumped alot of fuel for a long period of time in the left bank. The throttle body fixed thoes problems. Now the cats.

 

So was that the correct part number for the higj flows?

 

Yes. I replaced all four cats on my truck with two magnaflow 94106 cats as well.

 

Gotcha, I may have a bad hi flow myself.. I had a bad coil too.

94106 with no bungs (shop has to weld in some)

 

I just wondered if you go from 4 to 2 cats whats that does for emission testing, here in Colorado they are fairly strict.

 

The way the 4 cat system work are the front are your main catalyst while the rear's are mainly for sound. The 2005.5+ trucks switched to 2x 16" cats. They are slightly louder than the older 4 cat trucks because of this. I went from 4 to 2 and have no issues. Those magnaflow cats are nice converters. I have a spare one I will probably replace one of my potentially damaged ones. I'll snap some pics from it in a bit if anyone would like? Inside and all

 

Id like to see a pic from under the truck if you could. Would like to see how the factory pipe was modded to accept the two cat system. This way when my local exhaust shop says "duhhh i cant do that" i have a shot for reffernce. Hope you could pull kt off for me.