Well just wondering if anyone has removed the rear two cats on these trucks. I want a little more sound out of my truck. Its a little to quiet for me. I dont have the money right now to get a better exhaust. Trying to save money for a house. So my only option is removing the rear two cats on it. I was thinking of just cutting a section and bending the metal down and gutting the inside of the cat out. Then bend the tab back up and weld it shut and grind down the welds to make it look like nothing was removed.

Is this a good idea or should I just leave it alone. I cant see it hurting anything since the o2 sensors are before the rear two cats. Just need some opinions.

It's an '04, right? No, removing cats isn't even an option anymore. Nothing will run right or shift right without them (intact, I might add), and there isn't a damned thing you can do about it. Welcome to the new world of electronic sensors and controls.

*Edit: my son learned this the expensive way on his Ranger. After I told him the same thing. Fidiot cut off the back cat and disposed of it. $600 later, he could get it to run right again and the check engine light went back off.

Ok I thought I read somwhere that someone gutted the rear cats and it sounded good. Didnt sound like it was running bad. I also read that there was 2 o2 sensors in front of the the front 2 cats and the 2 o2 sensors that are between the 2 cats are just emissions. I couldnt see how the rear cats being gutted would cause it to run different.

I can see if I took off the front 2 but not the back. But I guess I will just leave them intact I guess. And yes its an 04

OBDII is a wonderous beast. You enter the world of unintended consequences. Older pre-OBDII rigs are completely different.

Does it have mufflers? I would think that cats + straight pipes would sound nice even on a newer truck. That's the setup that I have and it screams.

x2 on what's been said here...Also, if you can bend the exhaust down to break the inside of the cats out then bend them back up just with pure sweat and muscle, then I make 6 figures a year!

Ya it has a muffler. Its a Flowpro. I wanted the Flowmaster 40 series but the retard that did my exhaust put the flowpro on by accident and when I seen the bill and it said that he said its the same exact thing. I could take it off I guess but seen somewhere that someone gutted two cats so thats why I figured I would ask.

polarbear said:

OBDII is a wonderous beast. You enter the world of unintended consequences. Older pre-OBDII rigs are completely different.

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im going to agree with the bear on this. MOST OBDII vehicles you should not remove the cats...really bad idea especially if all you want is a better sound. pretty much anything OBDI and older its ok and wont screw with your computer controlled ignition. i have an 89 f-150 with the 4.9L. the cat on it has been hollowed out(previous owner did it). it doesn't not really effect the drive ability of my truck because it is a primitive computer system that is pretty much only going by general guesses in lamens terms. i can get away with it because 1) i only have one O2 sensor and its before the CAT, and 2) even that sensor isnt dead nuts accurate compared to the newer systems in trucks today.

Dude if it's volume that you're looking for then hack off that muffler. My buddy has the new mustang with just cats and no muffler it sounds REALLY nice. So I know those mod engines have it in em.

Chris.....he'd have to buy or fabricate a y pipe to take the place of the single in dual out muffler.

Ya I could remove the muffler and add a y pipe. I will have to think of what Im going to do now.

So I talked to someone that removed the rear two cats on their 06. Said its been like that for 2 years. Never had a problem. I dont know if he is just saying that but if he had problems why would he tell someone he never had any.

I don't know if this will help push you over the edge or not, a guy from another forum that I know has this. He has said that he has no problems, check it out.

mod motors sound BA without a muffler and still with cats, at least my '00 F150 did when I rocked that setup for a little while, then went to magnaflow cat back and it sounded BA as well!

Thats the sound im looking for. I just dont know how much of a difference my flowpro will sound compare to his magnaflow. Its almost louder then what I want but I really like it.

f150_fx4 said:

Thats the sound im looking for. I just dont know how much of a difference my flowpro will sound compare to his magnaflow. Its almost louder then what I want but I really like it.

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I know what you mean, Darren posted that a few months ago and I still go to it from time to time. It sounds so F-ing good.

Well I think that just convinced me to do it. But since I live with my parents Im sure Im going to hear them ***** when I go back to work and they hear me pull out of the drive way at 530 lol. With the flowpro muffler it might not sound that loud as the magnaflow. But thats fine with me.

f150_fx4 said:

Well I think that just convinced me to do it. But since I live with my parents Im sure Im going to hear them ***** when I go back to work and they hear me pull out of the drive way at 530 lol. With the flowpro muffler it might not sound that loud as the magnaflow. But thats fine with me.

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Keep your foot out of it when leaving the house, and you should be fine... let er rip once you get 1/8th mile or so from the house, so all the neighbors know your leaving..

Ya lol. Just showed my dad this video. He was like you just need a good set of headers Im like you going to pay for them. He said no. But he was like your truck probably sounds like that already Im like no this one has the rear two cats removed. He was like o so you just got to remove them some how. I told him my plan and he sounded like he didnt care. So hopefully in the next few weeks I can get it done.

f150_fx4 said:

Ya lol. Just showed my dad this video. He was like you just need a good set of headers Im like you going to pay for them. He said no. But he was like your truck probably sounds like that already Im like no this one has the rear two cats removed. He was like o so you just got to remove them some how. I told him my plan and he sounded like he didnt care. So hopefully in the next few weeks I can get it done.

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Not to be nosy, but did you pay for the truck?

I don't think I'd get permission if I payed for it.. if I didn't pay for any vehicle, I would be made to leave them stock. Parents sayin' "If it was meant to have it, it would have it from the factory"