hi-flow cat smog legal in CA?

Originally posted by Fmr12B:

Originally posted by Toadster:
my SHO Shop Y-pipe with high-flow cat passed emissions with flying colors... tried and true models should work well.

Just passed smog in June with my Sho Y as well. Neither Toadster or myself were running gutted pre-cats or Headers though.

And i think that the Pre-cats do most of the work and the underbody cat is just the added insurance. so if you run headers or gutted pre-cats you might pass on the high side. key word is MIGHT. are you willing to take the risk?
you could probably take the precats off and put your headers and when its time for smog, put your precats back on. its up to you if you wanna go through the hastle every 2 years.

I have MIL eliminators for sale. home made using surface mount components so the pcb is smaller than a nickel. i can shoot pics for you. shoot me PM if you'd like them.

ohh and i just bought new pre-cats and i really didnt feel the difference between gutted cats or new pre-cats.

Its not really worth the money IMHO. You might gain 1-2hp, but that's about it. The stock cat isn't really much of a flow restriction. Having said that, I did just pick up a test pipe myself, so do what you like...

Originally posted by GoldenTour:

And i think that the Pre-cats do most of the work and the underbody cat is just the added insurance.

The precats are for start up emisions, that why there so close to the heads so they light up quick. It is possible that you could pass emmisions with just the precats and no main cat. But ounce the car and main cat is hot, the precats do nothing but restrict flow, that why people get such big gains from headers, and as long as you have a proper working main cat, you will pass emmisions with headers no problem

Jeez Steve, going for full-on CARB legal, eh?

i was going to get a high-flow magnaflow cat to go with msds headers/ypipe but after reading all of this i am not so sure...

Originally posted by Matty K:
Jeez Steve, going for full-on CARB legal, eh?

F*CK the POLICE!, er uh CARB!

Ary, you can get a test pipe for the high flow, and keep your cat for smog time. that's what i plan to do. only need to smog once every two years in CA.

only lol

Originally posted by 111R:
i was going to get a high-flow magnaflow cat to go with msds headers/ypipe but after reading all of this i am not so sure...

Assuming you have a catback. Do you have any idea how loud this set up is gonna be?

Originally posted by dubkatz:

Originally posted by 111R:
i was going to get a high-flow magnaflow cat to go with msds headers/ypipe but after reading all of this i am not so sure...

Assuming you have a catback. Do you have any idea how loud this set up is gonna be?

uh nope

probably catback would be borla, trubenz, or a custom job i am looking into. i also didnt want something loud so would there be any way around this to make it smog legal?

-a

Originally posted by 111R:

Originally posted by dubkatz:

Originally posted by 111R:
i was going to get a high-flow magnaflow cat to go with msds headers/ypipe but after reading all of this i am not so sure...

Assuming you have a catback. Do you have any idea how loud this set up is gonna be?

uh nope probably catback would be borla, trubenz, or a custom job i am looking into. i also didnt want something loud so would there be any way around this to make it smog legal?

-a

as long as you have a main cat wether its hi flow or not you should pass no problem. assuming your engine is in good operating condition.

I'm not so sure about that after reading the first post in this thread by goldentour. You are right in that the engine needs to be running properly but he stated his readings were worse after he installed a high flow cat. It would be interesting to see exactlty what those readings were. I would also be curious to see smog results from other duratecs with a list of mods, mileage, etc. This way we could all know if it is safe to use various combinations and still pass smog.

Originally posted by Marky:
I'm not so sure about that after reading the first post in this thread by goldentour. You are right in that the engine needs to be running properly but he stated his readings were worse after he installed a high flow cat. It would be interesting to see exactlty what those readings were. I would also be curious to see smog results from other duratecs with a list of mods, mileage, etc. This way we could all know if it is safe to use various combinations and still pass smog.

He also posts
"i think the higher the flow, the more likely your toxins will just blow right by the cat. "

if you ever look into a cat you can clearly see nothing is gonna just "blow right by"

Understand. What really matters is the test results, does high flow = less effective? I can't remember the price of a stock cat it was posted a while back and I know it was expensive. If these high flow cats don't perform well enough to pass smog whats the point? The minimal if any hp gains don't justify the price.

Just for some additional info, I just swapped in a test pipe in place of my cat (higher flow than any cat) and I haven't really noticed any power difference at all. Like I had mentioned before, I think the cat just isn't much of a restriction in our cars. I think the money that you would spend on a high-flow cat could be better spent elsewhere.

How does it sound, any rasp or drone?

Originally posted by Marky:
How does it sound, any rasp or drone?

None, actually it is a little quieter than the stock cat surprisingly...

Originally posted by Marky:
Understand. What really matters is the test results, does high flow = less effective? I can't remember the price of a stock cat it was posted a while back and I know it was expensive. If these high flow cats don't perform well enough to pass smog whats the point? The minimal if any hp gains don't justify the price.

O i would agree 100% with that.
But like Paul just posted he gained nothing from removing it totaly so i doubt a highflow would help any. Maybe if you were running a super/turbo charger were you wanted zero back pressure. But a stock/lighty moded 2.5 nobody is gonna see any gains.

here are the before and after readings from 150,000 miles on Main cat and gutted precats.

Also in regards to noise and drone. I have a custom 2.50 dual magnaflow with out resonator.

argh the drone was terrible. i loved it at first but geez the drone inside the cabin just made me hate it once you revved past 4500rpm.

i did find my PCV valve unplugged causing unmetered air to go into the engine. and i think this initially caused my O2 readings to be high and then the o2 sensors just dump more fuel in. but at any rate i fixed and retested with the new magnaflow cat and the readings got worse!! i drove the car from carlbad to LA and then smogged it, so this shows that the cat should have been hot enough to work well.

my engine does not burn oil, i performed the UIM and LIM cleaning before testing and everything was surprisingly clean! if you look at my readings they show that the engine is in good condition except that the cats are not doing their job. Also i have put new precats, and i have not felt it different other than it is quieter and the butt-o-meter is never wrong.

but hey if you feel like you gotta try it do it. heck i did.

So you installed new pre-cats and passed?

Not quite yet. I also ordered a new underbody cat, and the one i received was the 2 bolt flange for the SVT and i have a 3 bolt flange. so i should be getting the new cat tomorrow. i will update the thread with the new numbers when i test next week.
Also, in LA county or at least in Pomona, CHP and local cops set up smog checkpoints and i really dont want to get caught up in this. so im going fully legal on my exhaust now.

hmm...ive only seen voluntary smog check points but that was yeeears ago. anywho, im going to be putting a 3L with headers and 2.5" exhaust. anyone think a test pipe will net any gains? or just not worth the extra cost.

For reference could you please post the prices?

who me? prices for what?

My reply was to goldentour.

Originally posted by Marky:
For reference could you please post the prices?

F8RZ-5E212-BC List $591.72 Inet $438.46 (underbody cat)SVT

F8RZ-5G232-AC List $365.95 Inet $271.17 (right bank)

F8RZ-5G232-BC List $358.78 Inet $265.86 (left bank)

XS2Z-9G444-AA List $103.78 Inet $57.67 x 2 (EGO monitor)

XW4Z-9448-AD List $14.46 Inet $11.61 x 2 (manifold gskt)

The NON-SVT 2.5l underbody cat is about 100 dlls less

yeah its expensive!! i dont think that i would ever gut cats again unless i was certain that they were plugged.

Thank you.

anyone know if it is illegal for junkyards to sell cats? ive been trying to find something to bolt to my WR headers and exhaust system

i have a two bolt flange but need a three bolt. stazi said i could take the whole setup to an exhaust shop and have them mod my stock cat to work but i was kinda hoping to find something that would just pop in.

i guess in the mean time ill drive around to some shops with my stock cat and headers to see if they can make it work. im running out of time though

i don't think it's illegal for them to sell CAT's, but i do think it's illegal to swap yours out without informing someone (can't remember if it's the DOT, or CARB)

I believe that it is illegal for wrecking yards to sell cats, at least in California.

Originally posted by Big Jim:
I believe that it is illegal for wrecking yards to sell cats, at least in California.

I think i have heard the same thing before.
Maybe because if its used they cant realy tell if its 100% working, and becuase it smog