I have a 97 f150 4.6 and I just put 3" exhaust from the y pipe, wanted to cut off the cats but the installer wouldn't do it becaue it could through the check engine light and the truck maynot run proper.Im getting a superchip micro tuner that i could use to turn off the check engine light.Would cutting out the cats doing anything else but get a better flow and better gas milage ?

 

I wanted to do this on my 97" 5.4 before but everyone said it would run bad without any cats. Most people on here suggest cutting all 4 cats off and putting 2 Magnaflow High Flow cats. I have true duels right now and if I touch my exhaust this is what I'm going to do.

 

I think some people have told me about an o2 simulator also that will keep the truck from throwing codes and will make it run right. I'm not sure where you get them. I THINK I heard ebay or Summit racing but I'm not sure Personally, I would just do two high flows.

 

im running no cats.in my 97 4.6L i have the front o2's in the down pipe and the rear o2's are simulated i got the simulators from RPMoutlet. dont know if it helped or not but it smells alot better. i cut my y-pipe off then took the down pipes off with the cats took them to a shop he custom bent a 2.5" pipe the same bends without the cats and drilled out the front o2 holes for 80 bucks. by law the shops can't remove the cats...its illgeal not to have them...dont tell on me!

 

The rear O2s have nothing to do with engine operation, they simply monitor cat life and will trip a code if something looks amiss. If you have no cats and it runs poorly its not because of the rear O2s, more because you drastically changed the airflow and a/f ratio.

 

yeah the sim's just lie to the computer and tell the computer that the cats are there and working fine. ive heard from people you dont need the rear o2's simed or anything the CEL will always be on thoe.

 

You could purchase MIL Eliminators to shut off the check engine light. All they do is eliminate the rear o2 sensors from the circuit so they dont trip your check engine light. If you dont get them or use the programmer as you stated, the computer will think that you are running too rich and back off on the fuel mix and your truck will run lean and risk detonation on high rpm's. Either wait until you get your programmer or pay the $40 for the MIl's. They are easy to install and make sure you tape them up good so they dont get wet.

I hope this helped some.

Also, when I removed my cats on my old vehicle, I lost all of my low end torque, but the high end increased alot. Also, my gas mileage increased a little.

Good luck,
Devildog101

 

The cpu doesn't make any adjustments based on rear O2 readings. All the sims do is keep the CEL off. If you are getting a tune anyway just have them shut the rears off, getting sims also would be redundant and a waste of money.

 

Yes, gutting/cutting the cats will throw a check engine light. Yes, your Superchips will *clear* the code, but it will keep on popping up, causing you to constantly run diagnostics on it. Depending on how many miles are on the cats, MPG should increase. It won't cause any harm to your truck. The power regained is amazing...

 

what are MIL's and where can you get them? Also does anyone make a pre-fab Off road Y pipe for our trucks?

 

yeah my truck i have no cats and a sensor eliminator thats changes the **** to where my check engine light doesnt come on and it runs beautiful and sounds like a bad *** ill try and get a video of it on here for u too listen too

 

Flowmaster 40 series and gutted cats anyone?

 

that sounds bad ***

 

Yes sir! My ran like sh^t - nothing out of the hole without cats. I put two HF Magnaflow cat's on and got all that back. Mannn, did that suck without cats.. - A freakin dog!! I couldn't believe the difference those cats made.

 

yeah my isnt that bad at all getting up and going off the start yeah its a lil slower but it dont matter to me i aint doing ne racing lol but when im at 30-50 and kick on it boy it gets up and goes