I failed smog for multiple reasons, all of which I have fixed, but I'm not sure about the aftermarket high flow cat it has. I'm pretty sure the guy I bought the 4runner from told me it has one. Will it cause me to fail smog?

 

I personally Haven't seen any results from a high flow cat, but I'm sure someone on here has, as most of the people who've had cats stolen went with high flow replacements.

Oh, also there are 2 different styles of "high flow" there are the ones that are actually cats, and there are ones that are just a straight pipe inside, that look like a cat externally. hopefully you have one of the 1st group.

 

Actually high flow is sort of an old term that is used for advertising catalytic converters. Back when cats first came out, they were made of beads packed into the housing over which the exhaust gas flowed (or at least tried to flow). Then some mfg. came up with the modern honeycomb design and started calling those "high flow" converters. So now that most every cat is the honeycomb design inside, calling that "high flow" is sort of meaningless.

There are a few true high flow cats available, they usually use an over sized block of material and have longer tapered sections and larger inlet and outlet tubes.

But cats do age and wear out over time and I find the lower cost aftermarket ones tend to do so faster.

 

I've seen some aftermarket cats that claim to be CA legal, but they cost a lot more than the others. They were still way cheaper than the OEM cats though. I would think any CA muffler shop would know what will work.

 

The cat is pretty new, I think it was put on in the last 2 years. I don't really know what kind it is, I just know it's not stock. Has anyone had problems with aftermarket cats or "high flow" cats?

 

the high flow cats are different from pass through cats.

mine has a pass through and it passed... barely but i passed 1st try
but i have a header and huge exhaust

 

Up here we have a sniffer system VERY similar to the CA system. Though we don't get bugged about aftermarket parts.

I passed with a hi-flow cat easily. If your trucks in good running order you won't have a problem...

 

yeah, you'll only really have a problem with the cat if the tests imply the cat is bad. then you'll have to replace it with a legal one.

 

I've got one, and I passed with great numbers. You'll be fine as long as your truck runs good.

 

ignore this, i meant it to be a message.