Ok, this question is for California owners? What exhaust combinations are putting out the most horsepower but still able to pass smog inspections? Can a California car run Long tube headers? How well do free flow cats work? Will free flow cats pass California emission standards? What about an X Pipe? Is the X pipe needed? What combinations are California owners running. I am looking for Passing emissions, HP Gains, sound quality, ease of installation.

I currently have Borla Quad tip Stingers which I would like to keep in the combo.

Let me know what works in Cali!!!!

 

No long tubes in california period.

Either do shorty headers that are carb legal or leave it alone if you are worried about smog (you will get quite a bit of people telling you it is not worth it)

X-pipes are legal as long as they have a cat and do not move the cats to any other location.

In regards to the high flow cats I am not too sure, i'll hope someone else on the forum from California has more input.

I debated over shorty headers vs ls6 intake... going to go with ls6 intake for now and get long tubes.

I wont pass smog but i'm sure i'll find a way around this eventually.

 

why are long tubes illegal? what difference does it make to emissions?

 

Long Tubes replace the cats with either nothing or an aftermarket cat ... in CA you cant touch the Cat at all for it to be CARB legal.

now keep in mind that in 2013 the rules are changing and you will not have to pass out the tailpipe just through obd2 and visual. LT's will still not pass the visual test, BUT its usually easier to find a shop that will work with you on the visual part more than one that will work with you on the tailpipe or obd2

I plan on getting LT's and figuring out a shop that will work with me which will be in 2 years when my smog is due

 

i always wanted to make a fake cat shell/header cover that would pass visual. what about the laws are changing?

 

the only change is 2000+ will not have the tailpipe test unless theres cause. I may try a shield to cover the LT's whenever I get some so it appears stock. Or i could just do what I did last year with my other car and pay the guy $300 to pass me

http://www.sema.org/sema-enews/2010/...-check-program

 

That makes sense. there is just not enough room under there to have the long tubes and the cats both.

 

The reason for the long tubes being illegal is actually twofold.

One is that the thinner tubing releases heat which means it takes longer for the cats to "light" - get hot enough to start working. This interferes with the validity of the "505 cold start" test which tests the emmisions during the first 505 seconds of dead cold to normal running temps.

The other reason is that long tubes require moving the cats from the original which is technically a Federal no-no, but is certainly a CA no-no.

Long tubes are an immediate failure of the visual inspection here and if you were stopped for a suspected emmisions control violation could be used as grounds to impound your vehicle. Yes, the LT's are a nice power gain, but no way they're worth getting your car impounded.

On the Z06, the stock manifolds flow pretty much as well as shorty headers (per several published dyno tests I've seen) so there really isn't a point for CA Z06 drivers. On my 99 the shortys did make a nice difference and they do have a CARB EO #, so I'm still safe.

I'd look at some of the other options available like deepr gears, a slightly larger but still smog-legal cam, and underdrive crank pulley (nice improvement), or a good fresh-air intake that is legal like the Calloway Honker. I have a Vararam (technically not legal, but most smog guys can't tell it's not stock) on mine for now and still have the stock airbox if I have a problem.