vettegator005

I have an 07 base c6 manual with kooks long tube headers b and b exhaust no cats. I understand i need to have cats on to pass the visual test but do they need to be factory cats or can i use high flows? Any suggestions on reputable exhaust shops in northern colorado?

bdanyluk

High-flow should be fine. Usually they just look with a mirror to make sure there is a bump where the Cats are...stock, high-flow, or cat pipe with no cats inside, they can't tell and won't ask as long as they see that there are bumps in the piping.

From my experience anyway.

haljensen

By definition it must be ORIGINAL cats in ORIGINAL position. It's a Federal law, not a State law.

You might get an ignorant Inspector or you might get one that's not honest and will pass you anyway.

carpe dm

I believe the Federal law states that the system must remain OEM for five years or 50,000 miles. It is a felony to remove/change any part of the system in that time frame. I have never understood why so many prople apparently do it anyway!? Not worth it to me.

Dano523

Your not going to pass the sniff test without cats.

timd38

You are assuming there is a sniff test. Question not a statement.

In Wisconsin, they plug into the OBDII port and as long as they don't get a code you pass. Story is, they are going to a visual inspection as well. I happen to have multiple homes, so my Corvette is at the home that does not have testing, so I am OK either way.

Dano523

In Denver, they put the car on rollers, shove a sniffer in the tail pipe and hook up to the obi port to check for fault codes, do a short run on the rollers that the computer tells them to take the car to each speeds for the sniffer test, pull the car off the rollers, and then do a pressure test on the gas cap. If all passes, then you hand them a check and they hand you the needed paperwork for DMV to get your new plates (note, your plate renewal card will tell you if you need a emission test that year or not for the new plates)

The emission test is good for two years most of the time, unless you pass one of the emissions monitoring check points that they get a reading as you drive by it, and if the cars output levels are too high, will need to have the car emission tested the upcoming year instead for plates.
Note, one of the moving emission check point is always on Speer on ramp by metro college as you are heading towards 1-25).

So not a question, but more of a fact since I keep a house in Denver for when I'm on holiday, and get to play the game for not only the Vet, but a truck that I keep there as well.

So no, without cats, your still not going to be able to tune the car lean enough to pass the sniffer test. With cats (even high flows), and a good tune to keep the car running lean enough, can even get away with running headers/cam, and pass the test.

And again, there is only a few cities in CO that require emission testing, but since the opt is asking the question, just happens to be living in one of the ones that does require emission testing for plates.

ls1121

you need a friend who has a friend...if ya know what I mean.

vettegator005

yeah i knew going into this that it was going to be a fight but i think welding cats on will do the trick if not then ill get a different tune if all that fails ill start making calls to my wyoming friends.

corvetteflier

Or move to Free Colorado: El Paso County.

05 Wreck

Why is Colorado worried about tail pipe emissions with all that pot smoke going into the atmosphere?

Dano523

Brown cloud cause by temperature inversion in the winter that just traps the smog over the city, instead of it being blown away in the summer months (why E-10 fuel manditory sold at the pumps only in the winter months).


It not at bad/thick as dropping into LA from the mountain off highway 15 where the smog looks like a fog bank you are driving into, but in the winter months, when you look at the mountains from the east in Denver, you can see the smog layer trapped in the air.

LA


Denver
[img]

Guard Dad

Not trying to be judgemental but having lived in SoCal all my life I'd like to point out that although I consider headers to be the birthright of every performance car owner the air here absolutely SUCKED back in the day and it is massively better now. Accordingly I've given up on trying to beat the system, the downside of an emissions citation is too great. There are many mods that make good power and will pass the tests so that's where my money would go.

But back to your question, without the OEM exhaust the inspector would have to be hungover or in your pocket to give you a pass. Do you have access to the factory system? Perhaps you could reinstall it. Your situation illustrates why the LS7 OEM exhaust is a popular upgrade for the LS3 in areas with comprehensive emissions testing. The LS7 exhaust produces more power without calling attention to itself and seems to keep the emissions in line too.

vettegator005

dont have the stock stuff but just because i have aftermarket exhaust shouldnt mean i cant pass emissions. having no cats is the big issue because of the visual inspection. Im taking them to a shop on friday so ill keep you all posted on what happens.

Dano523

Would be better off just taking the car over to A.I.R. to have Clint install the cats, then get it on a dyno to re-tune the car to get is to pass emissions (read one and done, instead of failing the test, and a major pain in the *** instead with re-testing).
http://ai-racing.com/

To note, even with the high flow cats, Clint will be able to pick up some more HP that the car is not producing now. The reason for this, with the change in atmosphere pressures (14.7 to 10.1), the PCM does not do a great job at compensating for difference in air pressure, and the car tuned for best HP in WI, is now running a touch rich up at the lower 10.1PSI air pressure instead. Also, he can make sure that the what was turned off on the PCM, if checked for by the scan, will come up kosher so you pass the emission test, first shot.

vettegator005

ive heard good stuff about this place. Any idea how much it would cost for a tune there?

Dano523

Tune and Dyno time (plus road time to finalize the tune to make sure it drivable) should be $400.
Note: Got to remember that $100 of that get kicked back to HP tuner for licensing to use their software (register Clint's dongle/software to your car) to tune the car in the first place via the HP software.

Takes two credits to license the car to the specific dongle/software.
http://www.hptuners.com/products/vcm...creditsfaq.php

DSOMZ51

I got my car tuned by Clint and plan to get in next week to update everything after my heads and cam project. I also talked to him about the emissions issue prior to doing my project and he told me that I should be OK with the cam size I went with... 230/234. He's a good guy, knows his stuff, and will take his time to get things right.

AORoads

Not sure this is relevant but a tune for 4900-5300 ft. above sea level may not be compensated for by the car computer than one at 873 ft. (Madison, WI). So, if you start going down to the "flats" aka eastern CO, things may seem odd with the car.

vettegator005

So 500 dollars plus high flow cats and welding labor. Probably looking at around 1500 total ball park then right?