what do i do w/ the o2 sensor ? also whats a good brand ? i dont want it real loud, a little mild maybe.(no cats.)

 

Well Ol' Bud
Sorry to say but youre out of luck!
This cannot be done with out cats the o2 sensor reads the air/fuel ratio
If you remove the cat this will send an incorrect reading to your engines computer causing the computer to lean your air/fuel ratio there fore your engine will not operate properly! I know this from personal expierance for about the first month every thing was fine then the symptoms started kicking in and i had to put cats back on now my check engine light wont go off! Gofigure
Hope this helps
JJ

 

if you say you dont want it real loud, then definitely leave the cats on. i know a guy with a 5.4 with headers, true duals and flowmasters with no cats and his truck is VERY VERY loud (100 times louder than mine and i have straight pipes also).

 

i'm not sayin your wrong jimmy, but how does the cats. effect the o2 sensor if there after the sensor ? and how did your friend do his donate54 ? thanks

 

if i remember right from what mike troyer told me when i asked about a program with no cats, he said that you would have to play with the values of the back two o2 senors to make it run right. the cats report a certain temp back to the computer , telling it how to run right. if you remove the cats then you mess with the reading the computer gets and it makes you run from what i figure too rich. but mike also told me that the cats are high flow and hold only about 2 psi, so all you would get out of cutting them off would be about 5 hp. too much trouble for me and then if you ever got stopped and they looked it would be one hell of a ticket, i live in ms and a guy had a dodge without cats and straight pipes, a cop stopped him for being too loud and gave him a $1000 ticket for no cats. but thats only if you get caught. anyway you really dont gain enought hp to mess with cutting them off.

 

i dont want it loud . i thought if i could do away with them i wouldnt have to buy 2 of them. but guess now i will. i really wanted true dualls . could you put the o2 sensor on just 1 side ? if you have a cat. on each side ?

 

The rear O2s only look to see if the cats are working. If you cut them out, you will get a check engine light. As stated above, the gains aren't worth the trouble anyway.

They do make devices called O2 simulators which will fool the signal to the computer. In short all you really have to do is add resistance (of the proper amount) to the signal. If you're really intent on doing it, get the O2 sims.

 

Yes signmaster, Summit sells O2 simulators that trick the computer into thinking the O2 levels are in nominal range even though the sensors are non-existent.

I wouldn't mess with removing or replacing the factor cats... You'll screw up not only emissions. Everybody I spoke to regarding aftermarket exhaust said exactly the same thing. Leave the cats alone. Almost all of them also said that the newer generation cats were much less restrictive than older designs and that replacing them with after-market "performance" cats were a waste of money. I've got factory cats, JBA headers and a somewhat bastardized cat-back system that definitely improved both my low end and gas mileage. No, my exhaust is not loud but you could do the same thing I did and have it as loud as you want by swapping a different muffler of your choosing or leave the muffler off all together. If you do that though you will likely lose some low end.

Just my 2 cents of anybody cares.

 

Ronhop,

I agree. I run my cats and will continue to. Just pointing out that if people are set on ditching them, they have other things to contend with as well.

Not to mention that running no cats is a federal offense and they can take your truck as evidence. It's just a matter of time and they will offer rewards to turn people in. Collect a $500 fine and hand out a $100 reward to keep them rolling in....

 

thanks for helping me out guys. i think i'm gonna stick w/ cats. the packages i've seen have the headers goin into a y-pipe, then cat. then i guess you can have dualls come back out of that. but thats not true duall exhaust. i just dont get it, spendin the $ to get headers and have them goin into a single exhaust. then back out so it looks like duall exh. what i want is true duall exh. could i have a cat on each side instead of a y-pipe and still use the o2 sensor ? thanks again, kelly

 

The way my exhaust is set up is the headers are JBA "Cat Forward", shorty headers that exactly replace the factory exhaust manifolds and bolt right up to the factory cats. The factory Y was cut out and a Flowmaster Y was welded in it's place. The Gibson cat-back is just welded/clamped in right after the Y collector. The order I did the exhaust mods were: cat-back, Flowmaster Y collector, headers. I currently have a 3" in and dual 2.5" out Dynomax muffler which replaced the original Gibson that had a baffle break loose.

I wanted to go with a Flowmaster muffler but my local shop here in the middle of nowhere could not get one that would fit the right way so I went with the Dynomax since they had one in stock. The baffle in the Gibson broke loose a week before a 2 week fishing trip and they just didn't have the time to get a FM muffler before I left. I am happy with how things turned out though...

I believe there are several posts out here where folks have just went headers->factory cats->duals out the back or side with no Y... You don't need to have the Y necessarily, just dual mufflers or no mufflers at all, if you want the noise.

Now, there IS a lot of debate over loss of low end when you mess with the Y by either removing it totally and going duals or doing what some of us did and replace the factory Y with a Flowmaster "Y". You really need to read some of the posts on the topic of "to Y or not to Y".

With the factory Y you have 2 - 2.5" pipes from the cats (the one coming from the driver's side is further restricted at the factory Y. Mine was restricted down to hair over 2") going into a single 2.5" pipe into the factory muffler. When you put in the Flomaster Y you will have 2 - 2.5" pipes going smoothly, with no restriction on the driver's side, into a 3" collector into a 3" muffler inlet... It's definitely a decrease in restriction.

Good luck in your research and implementation. Tell us how things work out.