Been browsing through the forums and decided that removing the cat would be a good idea. Would then use the non-fouler method to finish it off. When I went out to look at my truck I was a bit confused as to what I was seeing. According to this diagram my model has two 'mini cats" before going to a main cat. Also I have a for and aft O2 sensor on both mini cats and nothing on the main.



So now I am trying to figure out if I need to hollow out all 3 cats, use the non-foulers and I'm done; or is my situation more complicated than that?

Have a 2000 Ram 1500 5.9L with a CA smog clampdown engaged, meaning neutered.

Also is there anything else I can rip off, bypass etc. from the CA smog setup that will help with better power and mileage?

 

Well, if the truck is no longer in CA. I would just get a Federal direct fit replacement from Magnaflow.

 

just cut out all 3 cats and replace with a piece of pipe.

 

zman17 I would love to get a new system but price is an issue right now. I figured I have the time and the tools, might as well rig it until I can afford something better.

dodgeboy1979 Wasn't sure if it would be that simple of a fix. It just had me weirded out that there were no sensors within 2 feet of the main CC, and that the mini's had the sensors so close. Never messed with my exhaust before so I didn't know what to expect.

 

if you no longer have to pass an emissions test, then i'd just sawsall all 3 cats off, and replace each mini-cat a straight piece of pipe, and the main cat with a Y collector pipe. you can buy pieces of pipe from a parts store or from a muffler shop. if you take exact measurements to a muffler shop, they could even expand one end for a good slip on fit.

most commercial shops will not cut off a cat w/o replacing it since its about a zillion dollar fine. many will make pipes for you, or do a little after the fact welding for cash and no receipt or paper trail.

temporarily remove the O2 sensors to prevent damage as 4 of them are damned expensive. reinstall them all. non-foulers on the post-cat's can help eliminate cel.

 

I just did this... I feel ya bro..


I left the pre-cats alone... I kept the crossover, dumped the Y, put two magna high flows on and went into a magnaflow true x muffler (2 in 2 out, this thing is HUGE)...

It is much quieter than the 44FM I pulled off of it (1in2out) at idle, but a decided rumble when running...

Here is something for you you may find of interest- if you're replacing the o2's, get the NTK's that end in 035... as in the cali ones.. you will toss a CEL with the 039's..

eliminating the Y (highly rec'd, I wish I would have taken a picture of that thing when I cut it out) will cause you an issue relocating the post sensor bung.. you'll have to weld one in on the new pipe..

having cali is actually better imHo, because both banks are monitored instead of the one... this is your opportunity to lay in true duals, and after running that for about a week and about 600 miles- let me tell you, it BREATHES....

I ran 2.5" piping, but effed up and ordered the 3" in 3" out muffler, so I had to bump it up right before the muffler.. It's no big deal I don't think...

here is the bestest thing about doing this: I picked up about 1.5mpg.. absolutely 1.5mpg.. I THOUGHT I had lost bottom end.. but now I don't think so at all... here is the only way I can explain it:

It seemed, before, that I had to build some RPM's for the truck to move- but when it did, it lunged.. Now, that lunge is gone and it's smooth.. I can break the tires free MUCH easier now when I lay into it..

I just put new upwind 02's on last night.. I'll be watching for more improvement- it seems after about 50 miles today, that it actually has improved but I need more time..

If you go with magna high flow cats (2 small as opposed to one large, and the one with the bungs intended for upwind o2's) you can cap one of them, and put your POST o2 from your passenger side into the other.. the PCM doesn't know the diff, it just thinks you must have one badass pre-cat on the passenger bank..

Like I said, I highly rec moving to true duals since you have the cali emissions.. it is SO much easier than 49 state trucks because it's already wired..

another 30 cents on top of what I've already said: I ran the truck WITHOUT the magna high flows, and then went back and welded in the high flows- and honestly I couldn't tell any difference in anything.. sounded the same, drove the same, and my levi's dyno says it pulls the same.. just get rid of that damn Y pipe.. I wish I would have taken a pic of it- I swear, the pipes weren't cut out along their axis proportionate to reaching a shared 2.5" right before the third cat, they were flogging sleeved with a larger pipe and squeezed together making the individual pipes maybe an inch and a quarter, and THEN out to a 2.5" pipe... It was choke central...

If'n ya need, I can snap some pics in the morning..

oh- and those pre-cats... they are tiny indeed, and STUPID expensive to replace.. the area they occupy is silly small which means you hafta take the collector apart and work with em' on the ground.. the thing is, though, that they actually breathe pretty dang good... If it were me (and it WAS me last week) I'd just leave them alone.. It isn't them choking you up, it's the dang third one, but even more than the third it's that dang factory Y pipe..

 

somehow i get the impression you really don't like that Y-pipe. LOL.

edit - oops hit the button too soon.

is there any other extra emissions equipment on a cali besides the 3 cats and 4 O2's. he mentioned something...
CA smog clampdown engaged, meaning neutered.

 

like I said.. I had to take it to get the welding done because I SUCK at it.. and the guy who did it for me was just as surprised after we gutted the Y and checked it out..

as far as the sensors are concerned, he'll have to go with the cali sensors- I ordered them from sparkplugsplus.com, the part number ends with 035 for the ones he needs.. there are four of them- two upwind and two downwind, but there is nothing else that I've seen other than that.. the entire OEM rig is kinda silly, almost like an engineer was thumbing his nose at cali- the two pre-cats (shaped something like a football, and about a third smaller than one) are monitored upwind.. then the posts about a foot behind them... then the crossover and Y, then straight into an unmonitored big-ol-cat like we're used to seeing which is totally unmonitored..

I tried to convince an exhaust shop that it was a resonator, but they wouldn't buy it.. and told me the only way they would do the job is to replace it.. I'm glad I didn't go that route..

I have two small magna high flows in the same spot the big-ol-cat went, which is in reach of the passenger side post o2's factory wiring- so I just twisted the post sendor in the bung designed for the upwind on one, and capped the others bung..

I've not seen any codes whatsoever..

edited to add:
he can't drop the two sensors above the mini cats... his PCM is set to read differently than 49 state, and it needs those in place (individual banks) to keep the engine trimmed properly... dumping them into one will create issues.. that is what I'm guessing is the 'clampdown', and I'm also guessing that is on a software level- which is likely the difference in the two sensors as well as the rich/lean ratio/table on the cali pcm..

 

wow, thats pretty shocking that it gets necked down that much out of view

Some pictures would help me out if you get the chance

Definitely getting rid of the Y, dual exhaust is coming as soon as I can afford/talk wife in it. My truck feels the same way that you described yours, have to build the RPMs and then it rumbles forward, feels lousy.

Going to leave the mini cats as well, glad you mentioned it, I was not looking forward to working in that small space...didn't feel like dropping it

Sensors are 50k miles old and they seem to be working fine, if I did need to replace them think I could get the 035 for the downstream? or would that just upset thing having two upstream 039s and downstream 035s?

The clampdown is my term for what happens to all vehicles that have been sold in CA, they get lousy mileage, have lousy power, and you are extremely limited in what aftermarket items you can put on. Also the highway patrol liked to pull me over because it 'looked' like I had an illegal exhaust setup, it was the factory setup. Glad I am out of there and don't have to deal with it anymore.

 

if you replace the UPSTREAMS use the 135's... here is a link..

if you're not kicking a code, I would just reuse the downwind ones.. or get the $60ea downwind sensors.. Cali monitors those differently than the 49 state PCM's do I'm thinking..

the cost for you to go true duals is basically the cost of piping after whacking the Y out.. you could run two mufflers, or find 2in2out single chamber muffler which is in effect an x pipe.. according to folks who know a heckuva lot more about this subject than me, an X increases the scavenging effect (which is good) a LOT.. that magnaflow true x is sweet- I swear, I could drop a golf ball down one tube and watch it fall all the way through without touching the sides..

you can run the two pipes parallel down the same channel used for the factory and do whatever you want with them after the muffler(s).. mine dump under the rear bumper old school..

I ran the OEM upwind sensors until the replacement sensors arrived yesterday with no ill effects... I just changed them because I know they are aging, and it would be nice to see some improvement at the pump..