I currently have a few subtle modifications on my car...

Borla ATAK axle-back exhaust
Billet Grill (black) on upper and lower
Retro Shift **** (black)

Not much of all really. But I'd like to make additional modifications to my exhaust.

I live in an emissions (Colorado) state, with visual inspection, ODB testing and exhaust smelling. Can I do any additional modifications and still pass emissions?

 

High Flow Cats, you can also replace the Over axle pipes with 3" Piping. Also could do Shorty headers to keep cats and gain some sound with very minimal power gains.

 

Sounds like next up is midpipe and headers, and this is where it (almost) all just comes to preference. On no boost, you'll get a little more power out of an x pipe, and you'll get some more power out of long tube headers for sure, but some people prefer the sound of shorty headers and h pipe, myself included. To me, x pipe is more of a roar and h is more of a deep growl, and the difference between the sound of shorties and long tubes is kinda indescribable. My opinion to you, find a Mustang meet in your area, ask about different people's setups and listen to them. Youtube is a great resource for exhaust videos but hearing it in person is a completely different ballpark. Good luck.

 

As long as you keep the cats, you can do whatever you want downstream to pass emissions. With the tune, you shouldn't but MAY have a problem passing but it seems vehicle-dependent. If you fail, contact BAMA for an emissions-friendly tune.

 

First time post and brand new member here... I use google extensively to do a lot of research and have been reading a lot of the forums over the past month or so. THought I'd finally join you all...

I just added the GT500KR axle-back exhaust to my stock 2007 Mustang GT. I love it even though my wife thinks its tool loud... I was thinking of doing a CAI + tuner next but now I am wondering about the emissions as well... Are there any mods that drastically affect your ability to pass? (other than the tune already mentioned above)

 

Welcome to the crew! With axlebacks, a cai and tune, you should be able to pass emissions no problem whatsoever. The tricky part comes into play when you start messing with the cats. I just went through that headache, ended up registering my car in a county that doesn't do emissions just to save the hassle. In short: go for it.

 

OP,
I've never had a problem with the Colorado test.
Northern CO - Larimer County (same test as Denver)
Pypes X pipe - C&L CAI - 91 Tune
They sniff the exhaust pipes and the cabin.
They check the cats with a mirror on a pole.
It's a BS rip off for sure. CO should do a safety inspection instead.

Edit: I apologize OP, I'm at work and got a little distracted.
You obviously know all about the CO test.

 

Im in Aurora. You can pretty much do anything except be careful with your cats. If you replace them, you will want to make sure that your tuner can do an emission friendly tune like Nuke suggested. My 500 is super loud, so don't worry about how that.

 

OP,

I would stick with the factory catalytic converters if I were you. Some high-flow cats aren't emissions friendly enough to not throw a check engine light, let alone a sniff test. I wouldn't count on a set passing emissions unless you already know someone has the same setup with no problems.

Although Bama's tunes are fuel efficient and more emissions friendly than most, they cannot fake the feedback from the rear O2 sensors. Keep that in mind when choosing your setup.

Hope this helps!

Shane

 

Actually the Shorties are offering a lot of pick up in the low to mid range and you do get a deeper tone with them. The beauty of them is you can keep your Factory cats.
You can also get a cut and clamp X-Pipe for it and get rid of the Hybrid X/H pipe that is stock..
As long as you run stuff that does not require a tune you can return to stock before having to run it through Emissions and would not have to remove it before taking the car into Ford for service or warranty work.
Just things to think about.