So are you saying that if a high flow Cat is installed AND it meets emmision standards, it is still illegal? Logically the State should not care what you install as long as it can pass the emmisions standards.

Later, Ken

 

It depends on your state/county laws and whether or not a high-flow cat could still pass emissions. Maybe if someone can post the laws pertaining to it.

I doubt you would ever be prosecuted for modified exhaust in most states if the DBs are low enough and passed emissions.

If you are going to reduce restriction, a high flow cat is better then no cat.

Edit; couple things I found online;
28-955. Mufflers; noise and air pollution prevention; emissions control devices; civil penalty; exception

A. A motor vehicle shall be equipped at all times with a muffler that is in good working order and that is in constant operation to prevent excessive or unusual noise.

B. A person shall not use a muffler cutout, bypass or similar device on a motor vehicle on a highway.

C. The engine and power mechanism of a motor vehicle shall be equipped and adjusted to prevent the escape of excessive fumes or smoke.

D. Beginning with motor vehicles and motor vehicle engines of the 1968 model year, motor vehicles and motor vehicle engines shall be equipped with emissions control devices that meet the standards established by the director of environmental quality.

E. A person who violates this section is subject to a civil penalty of at least one hundred dollars.

F. This section does not apply to an electrically powered motor vehicle.
-------
California Vehicle Code
§ 27151. (a) No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of the vehicle so that the vehicle is not in compliance with the provisions of Section 27150 or exceeds the noise limits established for the type of vehicle in Article 2.5 (commencing with Section 27200). No person shall operate a motor vehicle with an exhaust system so modified.

(b) For the purposes of exhaust systems installed on motor vehicles with a manufacturer's gross vehicle weight rating of less than 6,000 pounds, other than motorcycles, a sound level of 95 dbA or less, when tested in accordance with Society of Automotive Engineers Standard J1169 May 1998, complies with this section. Motor vehicle exhaust systems or parts thereof include, but are not limited to, nonoriginal exhaust equipment.

 

Who said anything about a high flow cat, i said a cat.

 

Well, if you read the law as it is written in Illinois, (I don't know about other state's, but I'm assuming its the same) no modifications to the stock exhaust at all other than replacing it with another stock piece are legal.

 

You gave people thumbs up to running a high flow cat, so I assumed that's what you were meaning. My bad.

 

So in Texas, as long as you meet the standards for emmisions you are legal vis., Section D. That is, you can replace the OEM Cat and replace with aftermarket AS LONG AS it meets emmision standards.
The sections you cite from California appear to apply ONLY to sound levels; nothing about emmisions.
The difficulty I have found is when I ask a vendor if their "high flowCat" will meet emmision standards, they state, in effect, they do not know. So now the burden is up to you to demonstrate that a non OEM Cat meets State emmisions as well as being a benefit to your performance. For without the latter why bother worrying about the former.

Later, Ken

 

This cannot be true as you have stated it. That is, you take your car into an exhaust shop because your exhaust or Cat has a hole in it and unless they replace same with "another stock piece [i.e., OEM]" they are in violation. This cannot be true for it would put all these shops out of business.

Later, Ken

 

that's what I was going to say too. A high flow cat just less trouble... maybe a few less in the hp numbers, but not by much.. but they are expensive... or the last time I looked they were.

 

Oh sorry, you are right. I just read quickly i was giving thumbs up for running a cat period.

 

resonated test pipe ftw

 

wow..this thread got law crazy! LOL

Ends up im going with the Cobb TBE when it comes out in a few weeks. THey don't have a test pipe so dont worry about your children dying because of my cat-less exhaust lol

 

Cobb test pipe:

http://www.bulletproofautomotive.com...il.php?ID=6965

 

I hate how cat vs. no-cat always devolve into the environmental/law pissing matches. I don't think the OP needs a moral brow-beating from either side of the fence, as it appears as though he knows what he is getting into.

So to all the greenies and the wannabe state police, take a hike.

 

Really angers me that 67% of people (at the time of this post) think it is OK to run catless on what appears to be a daily driver.

Please do the rest of us a favor and keep your catalytic converter in place.

 

straight pipe will give so much more power especially future mods going past 350hp