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Hey all,

I just recently moved from the Kansas City, MO area to the Denver, CO area and have now become subject to emissions testing... I took my car to Air Care Colorado in Castle Rock and failed due to a fairly high NOx reading (everything else passed). I have Kooks LT headers, Kooks catted connection pipes and Corsa catback exhaust. I'm hoping Livernois can work some magic and adjust my tune enough to pass the NOx portion.

Here is my question - even if Livernois is able to adjust my tune appropriately is there still a chance that I could fail the visual (first test says Pass for cat visual)? I emailed a local shop and they said I will fail because I won't have EPA compliant cats, but I can't find anything via Google that substantiates the claim. Any help would be greatly appreciated since my current plan is to drive back to KC and swap out to my stock exhaust, but driving 10 hours each way with two small children in the car sounds awful...

Thanks,

Matt
 

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I dunno...i haven't had to emissions check mine yet...it is due soon tho.
If you got axlebacks i got factory manifolds and midpipe you can use/ have. Live a mile or so from air care in castle rock.

Clint at AIR in wheatridge/arvada could tune you to pass...
Also Nick at MAC autosport in Parker
 

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Or drive by mobile emissions testing vans 3 separate times... Probably a lot easier to pass... Just sayin.
 

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Or drive by mobile emissions testing vans 3 separate times... Probably a lot easier to pass... Just sayin.
Not gonna happen on a new arrival to the state. You must pass at an Air Care Colorado station. Also, if you fail once in the two year period that you have before emissions expire while driving by one of the mobile stations, you still have to go in. The vans are not all that most people think they are.
 

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The cats are the reason it will not pass switching the axle back won't change anything. Did you get it resolved? HFC's in Colorado normally do not pass the emissions test, which sucks for all of us. Unless you license out of city limits like in Elbert. I doubt you will have to swap the headers. Just start with the mid-section.
 

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The cats are the reason it will not pass switching the axle back won't change anything. Did you get it resolved? HFC's in Colorado normally do not pass the emissions test, which sucks for all of us. Unless you license out of city limits like in Elbert. I doubt you will have to swap the headers. Just start with the mid-section.
I'd disagree with this statement. My GTO had no problems passing with HFCs, and many others have had similar results. This is not to say that a car should always pass with HFCs, but the tune has a lot to do with it.
 

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Wow, I have never had a car pass with HFC's on it. My Evo Failed, My SRT-4 Failed and so did my 95 Trans Am. Putting the factory cats back on passed all 3 with ease. I guess you could tweak the hell out of a tune to get it to pass with HFC's, though. Either way just trying to help find a solution from past experiences not looking for an argument.
 

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Wow, I have never had a car pass with HFC's on it. My Evo Failed, My SRT-4 Failed and so did my 95 Trans Am. Putting the factory cats back on passed all 3 with ease. I guess you could tweak the hell out of a tune to get it to pass with HFC's, though. Either way just trying to help find a solution from past experiences not looking for an argument.
Can't say that I was looking for an argument either. Just stating my own personal experience as you were.
 

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Good to know

Well this thread is good info for me as i'm trying to figure out what I can do to the car and pass emissions.
 

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Discussion Starter #13
Sorry for not following up sooner, but still trying to finish unpacking since we've just been out here for a month now.

My brother and I ended up swapping in the stock manifolds/cats bolted up to the Corsa catback and returned the tune to stock. It passed easily and if you compared the two tests you couldn't even tell it was the same car.

NOx with LT Headers, HFCs and aftermarket tune = 3.8x vs. 1.5x limit
NOx with Stock Manifolds, Stock Cats and stock tune = .03x vs. 1.5x limit

If we decide to stick to the area longer than a year I'm going to have different cats welded into my connection pipes and my tune really dialed in. There is a chance that we head back to Kansas City next summer so I'm not going to spend a bunch of money on that yet.

Matt
 

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no need for air care for me...got my registration reminder , it says i passed already via roadside emissions testing....yay me
 
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