Passing Emissions
 

Hey guys, I'm still pretty new to the Subi scene trying to learn lots before I get in to really modifying my car. I have an 09 LGT 5EAT and would like to eventually start make it stage 2+ on E85. My question Is, how well do our cars do on passing emissions with that kind of set up? Also, anyone running catless DP and passing? Thanks for your help guys!

it'll help to know what state you are in.

However, catless is very unlikely

I'm in Denver, CO

I'm at stage 3, 91 oct, high flow cat, etc etc.

My plates renewal is coming up in Jan. I did a bunch of mobile spot drive bys, and I am hoping I passed!

I have a full cat less setup. That being said cash at a shell gas station let me pass. Ill be putting a resonator on though within the next two weeks because the noise on the highway is getting annoying and I'm tired of all the attention

hold on to your stock DP. Odds are that you will need to put it back on every couple of years to pass emissions. Some people get lucky, most do not..

Would a Catted aftermarket DP still give the same problem?

Denver is AirCare Colorado emissions testing. You need either your stock downpipe with the two cats or a special high flow cat that 5250 Performance can install for you.

With a traditional high flow race cat, like the kind that come on aftermarket downpipes, you can sometimes get by if you go through the mobile testing stations on on-ramps enough times, but most cars will not pass the rolling test.

That means every two years you have to swap in your stock downpipe, so when the stocker isn't on, you aren't emissions legal.

If you get one of the new technology race cats, you are emissions legal 100% of the time and it is no restriction to power.

Take into account there is a visual check as well. So even if you pass the exhaust test you can still fail emissions if you do not have the same # of cats as a stock vehicle does.

This is correct. My setup w/ a cobb HFC passes numbers. It does not pass visual.

FWIW, I got mine done not too long ago at the station up in Erie/Frederick area right off of Hwy52. I first went in with my aftermarket DP installed just to see how close I could get, and if I could get away with not changing it out with a little E85. The readings were somewhat close, but I failed on one, the NOX if I remember right. Went home, swapped my stock downpipe on, went back and passed with flying colors. I would just hold on to your stock DP and swap it out when you need to pass. Did not receive a visual inspection on either of the tests however.

Shortly before this, I had to take my old 2.5RS with an 02 WRX Swap and a bunch of other supporting mods including an external wastegate which made it a little tougher. I couldnt just borrow a stock DP, so after going to an exhaust shop, having them weld in a new OEM style cat and topping the car off with 3-4 gallons of E85 with a little splash of denatured alcohol to mask, she passed with flying colors as well.

I took mine into the emissions testing here in Fort Collins fully catless and failed, however I put on my stock DP and was fine.

I was stg3e with a CNT catted down pipe and passed fine visual and all. Just make sure you get the car really warmed up before you go in for test. I passed at the station on Countyline road and Colorado Blvd in case your in that area. My friend's 05lgt with fmic, e85... passed visual too, but he needed to add the race cat that mwiener2 is talking about

This is NOT correct!

They have changed the rules for how they test cars. It was meant to speed the testing process.

If you do not have any Check Engine Lights on and you pass the rolling sniffer test, they simply do a basic visual to make sure you have 2 O2 sensors and at least 1 cat.

If you have a Check Engine Light on, they will do a stricter visual inspection, and you're a dummy for trying to pass emissions with a CEL on. It's probably trying to tell you why it's broken and isn't about to pass.


I have passed numerous cars through AirCare Colorado testing and have spoken to the Director of the EPA and the head honcho at AirCare. Both have given the thumbs up for my cats. All the cars that have passed have had only 1 cat on them.

The most recent car to pass with one of my cats was a 2010 GT-R this weekend.

That's great news. I won't be changing my DP anytime soon then! When did they make this change?