I'm looking into getting a new exhaust on my 2007 Mazda 3i 2.0.
I'm interested in figuring out what setups are legal in our state. Specifically would an exhaust with a high flow cat pass emissions OK (my guess is yes).
How about a straight pipe or exhausts which delete the second cat? Does anyone have experience with this?
New Exhaust, what is legal
I'm with Alex. I doubt you'd pass with just a straight pipe. Could probably pull off the high flow cat with the roadside vans. There are people on here who know tricks and tips to pass emissions in next to impossible situations, so there's probably an easier way though that someone else here will know.

[color="Blue"]2008 Subaru Legacy 2.5i PZEV - Current Ride, 100% stock[/color]
[color="Gray"]2005 Mazda 6i Pebble Ash Metallic - Dead[/color]
- AuroraAxela
- Posts: 397
- Joined: Wed Dec 14, 2011 9:14
- Location: Aurora, CO
He's not a rotary engine, so he's not going to have any problems. I have a secondary cat delete on my MS3 exhaust swap http://www.coloradomazdaclub.com/forums/showthread.php?t=7870 and I did perfectly with the van. The equipment inspection will depend on how much of a stickler the inspector wants to be. Technically you have a cat, and that's all you need, since the secondary is unmonitored.
High flow cat should be ok, but I cannot confirm.
High flow cat should be ok, but I cannot confirm.
[SIGPIC][/SIGPIC]
[color="Blue"][SIZE="3"]2009 Mazdaspeed 3 GT[/SIZE][/color]
[SIZE="1"][color="Blue"][color="Blue"]POWERTRAIN: GTX3067R . Cobb AP . Cobb 3-port . Autotech internals . HTP 3" intake . cp-e FMIC . Forge v1 BPV . TWM STS . CNT Turboback
NGK 1-step colder . Bosch 3-bar . cp-e xFlex™ RMM/TMM/PMM . CorkSport recirc tube . Kosmic EGR delete
SUSPENSION: K-Sport coilovers . Whiteline RSB . custom MS6 wheels
EXTERIOR: cp-e TowPlate . DDM Tuning 5000K HID low/fog
INTERIOR: Defi boost gauge/cp-e defroster mount . NRG shift knob . CorkSport LEDs[/color][/color][/SIZE]
NGK 1-step colder . Bosch 3-bar . cp-e xFlex™ RMM/TMM/PMM . CorkSport recirc tube . Kosmic EGR delete
SUSPENSION: K-Sport coilovers . Whiteline RSB . custom MS6 wheels
EXTERIOR: cp-e TowPlate . DDM Tuning 5000K HID low/fog
INTERIOR: Defi boost gauge/cp-e defroster mount . NRG shift knob . CorkSport LEDs[/color][/color][/SIZE]
- AuroraAxela
- Posts: 397
- Joined: Wed Dec 14, 2011 9:14
- Location: Aurora, CO
My professional opinion is not to modify the factory designed emissions systems at all, or find an exhaust system that is rated to be a street legal equivalent.
It is my personal opinion that you should be fine with a system that has at least the one monitored cat, but I would have 2 cats to guarantee passing the equipment check. Or make sure you can always find roadside van checkpoints regularly. Granted I only have a single cat currently, but I passed well, and you should too, being that we have the same powerplant.
You'll be fine. Keep your stock exhaust in storage if you're worried, so you can swap it back on if needed for emissions.
It is my personal opinion that you should be fine with a system that has at least the one monitored cat, but I would have 2 cats to guarantee passing the equipment check. Or make sure you can always find roadside van checkpoints regularly. Granted I only have a single cat currently, but I passed well, and you should too, being that we have the same powerplant.
You'll be fine. Keep your stock exhaust in storage if you're worried, so you can swap it back on if needed for emissions.
[SIGPIC][/SIGPIC]
[color="Blue"][SIZE="3"]2009 Mazdaspeed 3 GT[/SIZE][/color]
[SIZE="1"][color="Blue"][color="Blue"]POWERTRAIN: GTX3067R . Cobb AP . Cobb 3-port . Autotech internals . HTP 3" intake . cp-e FMIC . Forge v1 BPV . TWM STS . CNT Turboback
NGK 1-step colder . Bosch 3-bar . cp-e xFlex™ RMM/TMM/PMM . CorkSport recirc tube . Kosmic EGR delete
SUSPENSION: K-Sport coilovers . Whiteline RSB . custom MS6 wheels
EXTERIOR: cp-e TowPlate . DDM Tuning 5000K HID low/fog
INTERIOR: Defi boost gauge/cp-e defroster mount . NRG shift knob . CorkSport LEDs[/color][/color][/SIZE]
NGK 1-step colder . Bosch 3-bar . cp-e xFlex™ RMM/TMM/PMM . CorkSport recirc tube . Kosmic EGR delete
SUSPENSION: K-Sport coilovers . Whiteline RSB . custom MS6 wheels
EXTERIOR: cp-e TowPlate . DDM Tuning 5000K HID low/fog
INTERIOR: Defi boost gauge/cp-e defroster mount . NRG shift knob . CorkSport LEDs[/color][/color][/SIZE]
Pass emissions first, then do whatever you want. Just be prepared to go back to stock every year or two. Don't know how often you guys have to get it done up there, another reason Colorado Springs > Denver. 

2015 Ironman Silver Veloster Turbo - Bone stock and staying that way
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1990 Crystal White Miata - Beater - Bignose 1.6L Swap, Robbins Top w/Glass Window, E-Codes, Air Horns, Brembo Rotors
Former Rides:
2011 Kona Blue Mustang GT 5.0
2009 True Red Mazdaspeed3 GT
2005 Flame Red SRT-4
erod550 wrote:Pass emissions first, then do whatever you want. Just be prepared to go back to stock every year or two. Don't know how often you guys have to get it done up there, another reason Colorado Springs > Denver.
^^^That's the most logical thing. If you are buying the exhaust and it is a straight bolt on it isn't hard to swap out when needed. Just swap the stock cats for the Straight pipe or single cat section.
If you are having a shop do it they may not do a straight pipe set up. Depends on the shop. You should let them know you want to be able to swap easily between the new setup and the stock cats.
Try just doing the muffler first and see if you like the sound of it. If you want it louder start removing cats. Remember that in a week or two after getting new cats or mufflers on the system will/should get slightly louder.
So I found this exhaust which is really damn cheap for an exhaust ($250 only):
http://www.ebay.com/itm/JDM-SRS-CATBACK-EXHAUST-2004-2005-2006-2007-Mazda-3-4DR-/380310185953?pt=Motors_Car_Truck_Parts_Accessories&hash=item588c40e7e1&vxp=mtr
There's a 100-page forum post on mazdaforums.com about it and generally people seem to love it for the price. Hence, I am highly considering getting it. However, it DOES delete the second cat.
What I'm hearing here is that I "should" be able to use it and pass emissions just fine (2.0L Mazda 3).
If I wanted to ensure that (keep my old exhaust in case), how easy is swapping between the two?
Would you recommend I get this thing having in mind I am NOT all that mechanically inclined and hence will pay a shop to install it for me? Would exhaust shops refuse to do it since it deletes the second cat?
http://www.ebay.com/itm/JDM-SRS-CATBACK-EXHAUST-2004-2005-2006-2007-Mazda-3-4DR-/380310185953?pt=Motors_Car_Truck_Parts_Accessories&hash=item588c40e7e1&vxp=mtr
There's a 100-page forum post on mazdaforums.com about it and generally people seem to love it for the price. Hence, I am highly considering getting it. However, it DOES delete the second cat.
What I'm hearing here is that I "should" be able to use it and pass emissions just fine (2.0L Mazda 3).
If I wanted to ensure that (keep my old exhaust in case), how easy is swapping between the two?
Would you recommend I get this thing having in mind I am NOT all that mechanically inclined and hence will pay a shop to install it for me? Would exhaust shops refuse to do it since it deletes the second cat?
I no longer have a second cat, however, I passed emmissions beffore i put it on... I would think that u should be able to pass just fine with just the one, but dont quote me to that. As far as switching between the two, (keep in mind that i have a 2.3 turbo mazdaspeed 6 and not the 2.0 mazda 3) mine was prty easy to remove the 2nd cat and catback parts of the exhaust system... all u need to do is jack up the car and its 4 prty obvious bolts and take off the hangers and ur set!
~~~Think I can make it?~~~:eek:
I will part with my mazdaspeed 3 exhaust for that price. I had a shop do a resonator delete which gives it a little more of a growl. From what I understand, it should fit fairly well with an exhaust shop.
Mazda3 with mazdaspeed exhaust
[ame="http://www.youtube.com/watch?v=1H5MzbFEUO4"]Mazda 3 with Mazdaspeed 3 Exhaust - YouTube[/ame]
My Car

Mazda3 with mazdaspeed exhaust
[ame="http://www.youtube.com/watch?v=1H5MzbFEUO4"]Mazda 3 with Mazdaspeed 3 Exhaust - YouTube[/ame]
My Car

IAlienzI wrote:So I found this exhaust which is really damn cheap for an exhaust ($250 only):
http://www.ebay.com/itm/JDM-SRS-CATBACK-EXHAUST-2004-2005-2006-2007-Mazda-3-4DR-/380310185953?pt=Motors_Car_Truck_Parts_Accessories&hash=item588c40e7e1&vxp=mtr
There's a 100-page forum post on mazdaforums.com about it and generally people seem to love it for the price. Hence, I am highly considering getting it. However, it DOES delete the second cat.
What I'm hearing here is that I "should" be able to use it and pass emissions just fine (2.0L Mazda 3).
If I wanted to ensure that (keep my old exhaust in case), how easy is swapping between the two?
Would you recommend I get this thing having in mind I am NOT all that mechanically inclined and hence will pay a shop to install it for me? Would exhaust shops refuse to do it since it deletes the second cat?
"Littering, and?..."


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