exhaust idea - help with cats and o2's

[XLoudFN97X]

OK, 103.4K on the X ('97 5.0L) and still no problems with the cats (knock on wood) but I like to be precautionary. I've been reading that the stock catalytic converters and o2 sensors are hell on these V8's (having 4 sensors and 4 cats) and I dont have big bucks to spend on OEM cats. I want to straight pipe past the front cats (or gut them) and get OBD II o2 simulators for behind those cats. This alone could save over $350 in OEM parts. I haven't decided on keeping the rear cats or not. Will the o2 simulators get the job done and should I go with high flow replacements in the rear or no cats at all? I'll be putting a Flowmaster 50 Series SUV muffler with downpipes (I like the no tailpipe look ). Do either the truck or the muffler require catalytic converters? Thanks for your help
~stu

 

[huskyfan23]

I think you'll need a custom chip if removing any o2 sensors, I hear the o2 simulators don't work on newer vehicles. You could get high-flow aftermarket cats for ~$50 shipped on eBay and get them put on, you don't even need 4 cats, but you do need the o2's without a chip. People here will ***** at you for even thinking about removing cats, just a warning

 

[j602]

Are the O2 sensors behind the first 2 cats or 1 behind each(4 sensors, 1 per cat)? Or 1 sensor behind each second cat? If there are no sensors after the second cats, then leave the first 2 alone, and cut out the second ones. If there are sensors behind the second cats, cut the first ones off, put highflows in place of the second, and get o2 sims if needed.

 

[XLoudFN97X]

OK what i know is that the first o2's are in front of the first cats and monitor the A/F Ratio from the engine. These are important! If they go bad car doesnt work right for sure. Then the secont pair of o2's are behind the first cats monitoring their performance. The rear cats are not monitored (meaning there are no o2's behind them). The front cats are the hella expensive ones that are pretty much non-universal because of size, shape, position, and sensor placement (yes, all of the above). They can be removed but as I understand it the second set of o2's ( without sensor simulators) will throw a CEL and a code saying the cats are bad (b/c they in fact are not even there). I don't know if this has any performance alterining behavior- Thats kinda the answer I'm lookin for here now... And screw the flamers if I want no cats. What I ASKED was would having no cats or less cats affect performance? Thank you.
~stu

 

[everythintech]

check mine out, http://www.cardomain.com/ride/1640301 , i dont have the last two cats, and i havent noticed a loss, nor any warning lights or codes. i like and havent had any problems...

 

[410Fortune]

I only have the front two cats, ditched the rear two, thats where I put my dual in single out muffler.
It works fine.

You can use 02 simulators behind the primary cat converters if you want, I stuck witht he 02 sensors in mine...

 

[XLoudFN97X]

The main reason i want to ditch the front cats is $$$. They will eventually go bad and I'll be faced with the following options: A) Spend $360+ to replace them, or B) gut them and spend $25 on simulators. The only reason I'd leave the rear cats is b/c I've heard that the X "likes" a little backpressure. I dunno, anyways... is that true?!

 

[XLoudFN97X]

i want to remove the fronts and keep the rears. if you have the fronts and not the rears that doesnt help me.

 

[Afboy143]

see you have the v8 so I am sure you will be fine with gutting your cats. My SOHC engine needs back pressure there for now that I have a dual flow exhaust system I need my catsfor backpressure. I would just cut out the stock cats and stick in high flow ones from ebay. Dont take my advise thou because I am not sure how that would work with the stock O2's. Check out ebay for Manaflow High Flow Cats. Im sure any good shops could cut out the stockers and weld these in. Trust me, Ive seen how the cats are and was heavily thinking of changing them when I got my exhaust done