My cat is bad (CEL code 67). Repeatedly cleared it but it comes
back. My milage is ok (30MPG), it idles just a little bit rougher.
What is the cheapest way to fix this and still pass emissions
testing.

1. a high-flow cat converter on ebay for $30+shipping.
2. a used OEM cat from a wrecked integra on ebay for about $75+shipping.
(I can't buy a used cat in my state from a salvage yard. -illegal to sell)

Will a cheapo $30 high-flow cat give me issues with the O2 sensor?
How does the o2 sensor attach to a $30 high-flow?
Will a cheapo $30 high-flow cat give me issues passing state emissions?
Does the high-flow make the exhaust sound different? Higher/Lower Pitch??

I think I read somewhere that a high-flow CAT makes the car feel less
powerful in the 0-30 acceleration zone..??? If this is so I definately don't
want to go this route.

Thanks
Tom

 

That cheapo high-flow cat isn't a cat, but most likely a dressed up resonator.

The best and legal way to do it would be to buy a carsound cat off eBay and have some flanges welded for it at a exhaust shop.

 

i second the carsound cat, i heard its the same as the random tech/magnaflow cat is that true?

 

Random tech makes their own, and I think Magnaflow uses Carsounds...

 

Yeah, go for an actual Carsound, Magnaflow, whatever. Some kind of brand name.

Like Epoch said you'll need to have flanges and o2 sensor bung(s) welded on. Or you can buy a Carsound with all the stuff already welded on from places like landspeedracing.com or ipsracing.com.

 

what if my muffler shop skipped the flange that connects to the b-pipe? Instead, he just welded the cat to the flange of the exhaust pipe. Would this pose a significant disruption in flow characteristics?

 

hey would a bad cat affect gas milage?

 

Nope... the only problem that it will cause is if you have to take of a single section of the exhaust.... With the way the cat is welded on, you'd have to take a lot more off before work could be done.