hello all. i gota question. right now on my 98 f150 4.6L V8, i have my rear cats deleted, then it runs stock (joins together, (h-pipe)) runs back to where the muffler was replaced and a Y put in, then out the back at 45's with 3.5" tips 18" long. Now... i was wondering what would happen if i took out the front 2 cats. i dont care about emission laws, we dont get checked up here. So, would it get louder? perform better, worse? i know ill probley get a CEL thats fine. Should i do it or not?

 

You'll get a CEL and your mileage/power will probably go TU too...the computer will have a hard time keeping your air/fuel ratio right.

Try a couple of aftermarket high-flow cats in place of the factory pre-cats if you want to open it up a little more. I haven't done my 97 4.6 yet, but I know a couple guys that have done aftermarket cats on their newer 4.6/5.4 trucks.

 

where do you find high flow cats for a good price?

 

ebay. most would recommend magnaflow part no. 94006, 94106, or 94306. 94106 is gonna be the loudest, 306 is polished and $20 more. those are about the only differences.

jake, im hoping to remove my rear cats on my '98 4.6. can you pm me? i'd like to ask you some questions, but i cant send you a pm.

 

so on 97-03 gen if you want to remove 2 of the 4 cats, remove the ones furthest back from the engine?

 

No cats will slug your performance. No cat only works on a rice burner. Ebay, Performance Curve, Performance Peddler, Summit Racing, HotExhaust, just some places that offer exhaust compounents real cheap.

 

I have the same year and motor as you. I originally removed stock cats and put in some high flow ones (not impressed, just open one up) then 1 year later decided to build a custom stainless exhaust while making other mods. Deleted cats all together (no CEL) and just put in the largest Magnaflow that would fit (it's huge). At the time I removed the cats, I put a few more washers on the O2 sensors to act as a spacer so that the sensor would not sniff too much of the richer exhaust, it worked I think because as I stated earlier, no CEL. I found out it was too loud inside the cab so I then intalled two small Magnaflows as resonators and that cut the noise level by 1/2.
It did not affect mileage or bottom end power.
After this and the other mods, I had to have the truck tuned to make the gains from the mods. At that time, the tuner turned the front O2 sensors off anyways. I have since passed the emission tests.
I suggest that if you get the CEL, try the extra washers as spacers, if that does not work you can then look to having the truck tuned and monitor your exhaust with a wide band. Sorry about the long winded suggestion(s) but that was my progression of the experiment.

 

alrighty, ill do some checking on ebay.