PTidwell Posted April 3, 2019 Share Posted April 3, 2019 Running into a problem...my Itasca has dual catalytic converters and my local muffler shop(s) have never seen this before. They must be replaced. In California this is a huge problem. All the CC materials I’ve read say the Toyota 3.0l V6 uses only a single converter. Mystery. Any thoughts? Quote Link to comment Share on other sites More sharing options...
Odyssey 4x4 Posted April 3, 2019 Share Posted April 3, 2019 Are they both in line on the same pipe? Is it possibly a custom dual exhaust someone did? Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted April 3, 2019 Share Posted April 3, 2019 57 minutes ago, PTidwell said: Running into a problem...my Itasca has dual catalytic converters and my local muffler shop(s) have never seen this before. They must be replaced. In California this is a huge problem. All the CC materials I’ve read say the Toyota 3.0l V6 uses only a single converter. Mystery. Any thoughts? Our CA 90 also had dual cats, on the same pipe inline with each other. I think they were factory! Smog shops eyebrows were raised for sure! They found some reference for it and passed it 3 separate times. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted April 3, 2019 Share Posted April 3, 2019 We don't do any inspections here, so I'm no expert. Any chance you could go an discuss this @ your local smog testing place? Give them you VIN and ask if their system says if you need 1 or 2 cats? Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted April 3, 2019 Share Posted April 3, 2019 Also note that some aftermarket replacement cats for the toys have inlet and outlet reductions inside the cat. The pipe on the outside might be the same size as your exhaust pipe but inside the cat the diameter is reduced. Possibly not a big deal but in my opinion there should be no restrictions in pipe diameter. How do I know? I did my own cat replacement on a stock 22RFI turbo exhaust. I was checking out the cat before install and discovered the reduction. The factory cat had no reductions. The parts guy had no explanation and in his opinion was not a problem, I disagreed. I busted out the insides of my old cat and ran it, eventually installed a custom larger diameter system and cat. Quote Link to comment Share on other sites More sharing options...
defrag4 Posted May 18, 2019 Share Posted May 18, 2019 My rig was built in california and also has the dual cats, finally getting them chopped off down here in Mexico, let that puppy breathe! no emissions in our home state of FL, good luck with california Quote Link to comment Share on other sites More sharing options...
ednelson100 Posted May 18, 2019 Share Posted May 18, 2019 My 91 Itasca also has the two inline cats. I have purchased a new single cat and muffler and am getting ready to install and use 2 and a quarter inch pipe. Like Gulfstream mentioned when I look in the cat and muffler the pipe is reduced. I guess that does not matter? Could you let me know how yours comes out, defrag and if it makes any difference on you 3.4 performance? Quote Link to comment Share on other sites More sharing options...
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