Hi Everyone,
I had a question about the two rear catalytic converters. I have 97' F150 with the 4.6. Now I know there are two cats in the front that are kind of on a bend and then theres two bigger ones behind them. I wanted to know If there would be any disadvantages to removing them and would I pass PA state inspection if I did? Thanks for your time.

 

cut all 4 off and then put in two magnaflow highflows cats part number 94106 you will pass as long as you have all you o2 in the right place. pm if ya got any questions and you tube highflow cats f150 if ya want to here my setup

 

Where is the right place to put the o2 sensors an what about the rear o2 senors will I need to cut an cap of the wires or what?

 

Well That's What I was thinking. I want to remove the back two and then replace the front two with high flow magnaflow cats. Now with that cat setup can I put a cherry bomb on, on top of that and gain more sound and power? Or will I just get more sound and lose power. And where can I buy the front aftermarket cats I can always find the back ones but not the fronts. And I have a welder but that is really gonna be a pain to get up underneath the truck so do they make like clamps and hoses to do this kind of stuff. I can weld them but that would be such a hassle. Sorry for all the questions just wanna do this right. Thanks again.

 

The right spot for the rear O2 sensors are about an inch behind the new hi flow. The fronts try to keep them in the same location so it does not interfere with the a/f ratios. No you will not free up any power with a glasspack. You can't gain any more power than the engine makes, only free up. IMO the hi flows and glasspacks will sound like you're 16 and dating your cousin. For a quality setup: get rid of the factory Y and replace with an aftermarket Y for single or X for duals and for pipe go 3" for single or 2.25/2.5 for duals with either Borla, Magnaflow, or Dynomax bullets. Welding may be a pain but it will be a lot easier than fighting exhaust leaks.

 

keep it 2,25 or 2,5, 3 is to too big and would not recommend it as for a muffler i had bullets and they were quiet because i was so used to my straight pipes so i switched to a bullet on one side and straight on the other and like that setup the best.

 

Bringing this thread back from the dead. I still have yet to touch the cats. But the back cat on the drivers side has been rattling and is very irritating. I don't think the cat is bad because the truck runs fine no difference. I was told it could be a heat shield? If this is the problem I will just remove the shield. If it needs to be replaced are aftermarket cats worth the money? I know they probably don't do anything for performance but I would like the extra sound if they do that at least. And no I'm not cutting off the cats because they are there for a reason. Also if I only put one highflow cat in the exhaust system and didn't do both sides would it effect my truck? I don't want to replace both as I just want to fix the rattling and not redo the whole exhaust. Sorry for all the questions just wondering what my options were. Thanks- Zach

 

The high flows will give a little sound. If you do one side, it's a wise idea to do the other side. Try the heat shield and see what is rattling and go from there.

 

Okay thanks for the reply. I will check the heat shield first. Also I know the front cats are the ones that monitor the a/f ratios and i would never do just one side for those. So could you maybe explain what the back cats do and what would be affected if i only did one side. Thanks- Zach

 

Bump