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Discussion Starter · #1 ·
Two questions:

First, if I wanted to stay completely CA street legal, what exhaust changes can I make? If I have to keep all the cats to stay legal, are high-flow cats avalable for all three, or just the "main" one?

Second, from what I have been reading on the forums, it sounds like I can probably pass smog with only the "main" cat in place, and even then I could switch to a high-flow cat for increased horsepower. The other two cats would be replaced by straight pipes. How thorough would a visual inspection have to be to catch it? What are the ramifications if I get caught (fix-it ticket, major fine, etc.)?

Thanks
Future WRX owner
 

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Unless the laws have changed, there is a Federal law that prohibits removal of any catalytic converters, unless it's damaged. I personally know one person with MRT's turbo-back exhaust (the one with the cat right next to the turbo), who has successfully passed the smog test.
 

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Prince Ali said:
I personally know one person with MRT's turbo-back exhaust (the one with the cat right next to the turbo), who has successfully passed the smog test.
I thought you had 4 years before needing testing (in CA). Why did your friend test so early? Was it not a 2002 WRX?
 

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Well, if a cop decides to be an a-hole, he can tell you to go to a smog referree. So it's possible that's what happened.
 

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Prince Ali said:
Unless the laws have changed, there is a Federal law that prohibits removal of any catalytic converters, unless it's damaged.
Can you say ball-peen hammer? ;)
 

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Here's the rundown...

The smog laws in this country are archaic. They require you not only to pass actual emissions output (what crap comes out the tailpipe) but a [email protected] "visual" inspection to insure that within six inches of any cat has been tampered with. This is a real problem when you want to remove them completely:D . Here's the deal: what really matters, the junk that's actually coming out the tailpipe and polluting the air or having a cat "look" like it hasn't been tampered with? If a car passes the acceptable amount of smog out the tailpipe with tampered or missing cats, who cares? Conversely, if a new car has cats and still pollutes, it is creating a problem.

The stock wrx motor with NO CATS will pass almost all federal emissions requirements in almost all states. It runs that cleanly. But, the laws haven't kept up with the technology and they still have to visually check for your cats, even if the car isn't polluting.

This is ridiculous. Here's how to get around it. Do these steps from first to last, most legal to least. Anyone of these setups will work, pick one depending on how comfortable you feel:
Easiest way is to gut the uppipe cat and put on a cat back exhaust. No laws really broken, they'll never know the uppipe's gutted, and the car will still pass.
Next, I don't know of a single smog tester in the country who would look to see if the uppipe is original. Just replace it with aftermarket, they'll never know.
After that, gut the cat after the downpipe. Even with just the cat in the dp working, you most likely won't throw a CEL, and you'll pass emissions and look legal to the techs.
The next option seems to be the most popular (it's also what I'm doing). Throw on a nice turboback exhaust and either replace or gut the uppipe. Also, get a CEL fix. I would recommend that you still get an exhaust with one hi-flo cat in it, just in case a cop wants to look under you car he can't fine you on the spot - he most likely won't know what he's looking at and even if he does as long as he sees cat heatshielding he can only order you to get a smog test done. When a smog test comes around (either due to time or law enforcement), unbolt the turboback and rebolt the stock exhaust back on. Totally legal. When you pass and get home, put the turboback back on. I don't know about you, but I have no problems cheating a corrupt law.:D
Civil disobiedience baby...I'm a rebel... yeah...;)

Hope this helps.
 

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djrez4 said:
Can you say ball-peen hammer? ;)
I would NEVER intentionally damage my cats. This is what happened. I was driving my car and obeying all speed laws when all of a sudden a big rock fell of the truck in front of me and punctured both my downpipe and midpipe cats. I had no choice but to replace my exhaust with a stainless steel unit and a hi-flow cat.
 

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stilesg57 said:
Here's the rundown...


The stock wrx motor with NO CATS will pass almost all federal emissions requirements in almost all states. It runs that cleanly.

Hope this helps.
I'm not sure about this. One of the reasons WRX was held back from the US market was related to pollution problems. If you look at the pollution sticker on a new WRX, you'll see that it falls in the middle of its group even with 3 cats.

I think if the car was that clean, Subaru would have certified it as an Ultra Low Emission vehicle.
 

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QuickSilver said:
I thought you had 4 years before needing testing (in CA). Why did your friend test so early? Was it not a 2002 WRX?
It was a used 2002 modified WRX and my friend wanted an emission-legal car. I think a smog check is required when a car is sold no matter how new it is. A clean smog check was part of their deal.
 

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Imagine all the poor suckers who put JDM engines in their 240SXs. I'm going to be one of those suckers soon. I think smog laws are retarded. It shouldn't matter what's under the hood as long as the pollution it generates is accecptable, and not ridiculous (ie. Suzuki Swift)
If Hondas make ULEV, can ULEV honda owners commit suicide using the exhaust pipe? Or how about the Sentra CA? The air in the front of the car is dirtier than the air in the back.
 

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AREITU said:
If Hondas make ULEV, can ULEV honda owners commit suicide using the exhaust pipe? Or how about the Sentra CA? The air in the front of the car is dirtier than the air in the back.
I guess they could, but it would take a reeeeeeeeealllyy long time before enough CO was produced.:p
 

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Prince Ali: the WRX emissions output falls in the middle of its group because its group consists of 100 hp ULEV corollas and civics. This group is at the very low end of pollution. A Suburban with the 6.0 L gas engine puts falls in the high end of its car group - big trucks and SUVs. By comparison, a WRX puts out less than 1/10th as many pollutant PPM (parts per million) as Chevy's 6.0 L marvel of efficiency. Basically, to pass federal emissions output standards you need to put out just a tad more pollution than a Suburban or better. This is a lot of room to play with, trust me...:D

BTW, a friend of mine is a manager at an emissions testing facility here in CO. After hours he and I ran my WRX on the sniffer with NO cats and it passed the minimum requirement! I was surprised too, but I told a trusted mechanic that I had, ahem, heard about this guy that had done the unthinkable act of removing his catalytic converters from his WRX and still passed the smog test up till the visual part, and he smiled and said he wasn't surprised. FWIW I don't know about CO emissions requirements, but the scale they use has to do with something and if you blow over 7.3 somethings you don't pass. With no cats my WRX blew 6.4 somethings out the tailpipe, plenty of room:D

Oh yeah, and about the emissions reasons that kept the WRX out of the states, those were minimal (they could have been changed if Subaru wanted to) and were somewhat self-imposed by Subaru as they didn't want to have to redesign the exhaust system in the next few years to pass new requirements - by meeting LEV standards they have ensured that they won't have to look at it again for at least the next 20 years. Also, they didn't want to ruin their image with the tree huggers in the northwest that make up a pretty big chunk of the North American market.
 

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stilesg57 said:
Prince Ali: the WRX emissions output falls in the middle of its group because its group consists of 100 hp ULEV corollas and civics. This group is at the very low end of pollution. A Suburban with the 6.0 L gas engine puts falls in the high end of its car group - big trucks and SUVs. By comparison, a WRX puts out less than 1/10th as many pollutant PPM (parts per million) as Chevy's 6.0 L marvel of efficiency. Basically, to pass federal emissions output standards you need to put out just a tad more pollution than a Suburban or better. This is a lot of room to play with, trust me...:D

BTW, a friend of mine is a manager at an emissions testing facility here in CO. After hours he and I ran my WRX on the sniffer with NO cats and it passed the minimum requirement! I was surprised too, but I told a trusted mechanic that I had, ahem, heard about this guy that had done the unthinkable act of removing his catalytic converters from his WRX and still passed the smog test up till the visual part, and he smiled and said he wasn't surprised. FWIW I don't know about CO emissions requirements, but the scale they use has to do with something and if you blow over 7.3 somethings you don't pass. With no cats my WRX blew 6.4 somethings out the tailpipe, plenty of room:D

Oh yeah, and about the emissions reasons that kept the WRX out of the states, those were minimal (they could have been changed if Subaru wanted to) and were somewhat self-imposed by Subaru as they didn't want to have to redesign the exhaust system in the next few years to pass new requirements - by meeting LEV standards they have ensured that they won't have to look at it again for at least the next 20 years. Also, they didn't want to ruin their image with the tree huggers in the northwest that make up a pretty big chunk of the North American market.
I sincerely hope you're right. I really don't want to put my old exhaust back just for the smog check.
 
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