catalytic converter question
 

I have a 96 Ram 1500 318/220K+ miles...daily driver, part time hauler. The cat isn't clogged but obviously bad...no temp increase front to rear on cat and #2 O2 sensor imitates #1 O2 sensoron the scanner. Fuel trims great/hovering round 0, both long n short term trims at steady engine load and normal operating temp, no money light (can't figgur that one), great power band n okay MPGs. The exhaust is leaking aft of the cat n the muffler is just about rusted thru...cat has over 150K miles n like most 2nd gen Dodges, ol blue once suffered the dreaded celibacy of the plenum, however, I repaired her long ago (Hughes). No sniffers for inspection here in DFW, are there any advantages to replacing the cat along with the muffler, say higher mpg, better performance, etc?

Your exhaust will flow better, and be a bit louder..... so, maybe a bit better power, but, likely not enough to notice, unless the cat really IS clogging, in which case, yeah, you'll notice. Same goes for fuel economy.

Then, of course, there is the legal requirement...... Federal law mandates that it be there, and in proper working order. (thus, inspections/tests/whathaveyou in some locales.) Depending on local laws, they might REQUIRE a 'stock' replacement, and not permit use of aftermarket parts.......

On the pre-98 trucks, I don't think the PCM cared very much about cat efficiency. Mine was hollow when I bought it, I drove it for seven years, and it NEVER set a code for the cat......

96 had a recall on the cats. Is this a replacement from the factory? Either way i would replace it with a magnaflow cat. I think they are 50 state legal but not sure. I had mine on about 50K and replaced the rusted muffler with a 304 stainless one.

I second the Magnaflow cat. I love mine. I originally had the oem style Magnaflow high flow one, but I had to replace it recently when I did my headers. It wasn't bad, but I needed a different size. This time I went with their spun style converter.

You will notice an increase in power with a Magnaflow. I'm on my 2nd one. And DFW used to smog as every vehicle had the sticker on the corner of the windshield. Not sure how you don't have it unless that changed somehow. Or just hollow it out and drive.

MPGs are noticeably down, but I think that has more to do with alcohol in the fuel n age, than the cat (I might be wrong). 20 years ago, ol blue used to average round 20 on the hiway n maybe 15 combined (if memory serves) but now hiway turns in at best 15/17 MPGs. depending on the gas I get (gas station tanks recently filled or not). Did the throttle body mod n it seems to have power on the hiway when layin' in to her. The #8 plug as clean as all the rest. Thnx for the advice guys. Ellis county just south of Dallas, Dallas or Tarrant county has no tail pipe sniffing for inspection, never has as long as I've been here/round 12 years. They use the computer spying method here, probly has something to do with cost to the inspection station n the state won't reimburse. Ive been lookin' into the Magnaflow cats n exhaust, seems to be the best bang for the buck. Don't have any record as to the replacement cat if it's factory or not. Thnx again.

15/17mpg is EXTREMELY good. I see 12 city and maybe 14 on hwy.

Just throw on a Mag cat and keep driving. You're doing great.

When I changed out my stock catalytic converter, I went with a Magnaflow Converter 99047HM (dual 2" inlets, 3" outlet, front O2 sensor port), so I could get a bit more flow with 3" exhaust from the back of the converter to the rear. I also added some 3" pipe into a Dynomax UltraFlo Welded Muffler #17233 and a custom 3" tailpipe. The setup flows and sounds nice.

Ramman, I'm lookin' into some 1.7 rockers (found some in a bone yard corpse but they wouldn't lemme strip the engine, ah well). I looked at getting a new F150, but when I saw the price, I said to meself..."self, I can add lotsa cool stuff to 'ol blue and gas 'er up a whole bunch ta boot for that kinda money"...not to mention, I just haven't been able to kill this beast with neglect. Recently resealed the tranny cause just about every oil seal had crapped out. I was pleasantly supersized to learn the synchro's, bearings n gears still seemed to be in petty fine condition. Well, 'cept for the 1st upshift of the day when it's REALLY cold (she clunks into gear 1,2 n 3). My few "repairs" to get her up to std's for another 20 years has turned into a restoration n the cat n exhaust is my last treatment of the drivetrain. I was also surprised to find that all the u-joints are still good after 22 years n 220K+ miles...wish I could say the same for the paint...gggrrrrr! Still gathering up the parts for 4wheel ABS...I've been told that's a big mistake, time will tell.

AtomicD...has the 3" pipe set off your money light? I've read that the lack of heat due to better flow can hurt the feelings of these old computers. I have the factory pipes still n some in the mad monk squadron says otherwise...any thoughts or advice?