If i was to remove my catalytic converter i know the ecu will throw a code obviously but i wanted to see if those extension bungs eliminate the check engine light, my main concern is emissions here in NY. They plug the car in for emissions (no longer with the smog probe etc..)

So will the o2 extension bung eliminate the CEL ?

OR

Is there something else that can be done ?

Also if you have any tips or advice from personal experience please let me get your 2 cents...thanks.

 

i would reccemend a magnaflow high flow cat. im not sure why you would want to go catless, but the power/flow increase between cat/catless, from my experience, isnt worth the cel in a daily driver. if its a track car, go for it. if not, the highway drone and cel are really not worth it.

i recently was running just a test pipe with my new header. it was obnoxious. the magnaflow high flow cat gives it a nicer tone and wont cause a cel.

 

What year is your car? People reporting catless drone with stock exhaust is BS. I don't know personally about bungs, but bottom line if you want to pass emissions don't go catless. No matter what you do, get a tune.

 

its an 05, its not a daily driver AND i will not be using stock exhaust, ill be making an exhaust out of 2.5" titanium.

 

Since you are doing a custom exhaust, drone will be a big possibility. It's not a DD? Do you care about drone? Although not legal, one in your position could put the cat back on when emissions are due...

 

Ian, I dont care about the legality and i dont care about drone. It wont be a daily driver BUT i will be driving it around a couple days during the week. My main concern is emissions when it comes time to inspect and when the car is plugged in i dont want it to show a rear o2 fail. I know i can use the 90* o2 like this:
http://www.ebay.com/itm/1x-O2-Oxygen...-/331127313934


Again loudness/drone isnt a problem for me, my last car made 718hp and had a straight pipe (no resonators/muffler) and an external wastegate dumping out the side bumper so yea... heh.

 

https://www.outmotoring.com/mini-cat...or-spacer.html

i think this would solve the issue, ill be doing the same thing of going catless, but if my tune cannot code out the CEL ill have to be innovative. possibly with the thing above. I already have a magnaflow highflow cat just incase i dont enjoy the sound

 

ohh thats interesting, ill definitely buy this instead of the ebay junk. Salty once again, thank you!

 

NY doesn't test "emissions", technically speaking. If they did, all catless cars would fail.

With a functioning O2 simulator, whether it be electrical or mechanical, you will pass OBDII diagnostics just fine. The best mechanical O2 simulator I've used thus far is made by Vibrant, and it comes with 3 different inserts, as to allow for adjustment of restriction to the O2 sensor. This allows you to fine tune the simulator if one size still results in a P0420 code.

 

Yea in NY they plug in the ECU. Alright, thanks alot for all your input guys.

 

I have a catless DP and also have tried 2 of the O2 bungs and neither worked to prevent the O2 code.

However, others have used these and they worked ok.

 

I figured it was hit or miss, I really hope I can get away with one of these.

 

you could get a high flow cat from magnaflow for a few bucks more than that spacer on outmotoring.

then you have 100% no light.

i dont have the dyno to prove it, but if you do some reading online, 9 times out of 10, youre looking at a gain of like 2hp going catless.

to each their own. i ran my car catless for a few months. then emissions time came and i had to either pay to get my stock cat welded back in, or buy a high flow cat anyway.

the magnaflow model that fits our cars has a 2.5 in/out. im pretty sure it was like ~$65 on amazon.

again, im not saying youre wrong for going catless. you just have to ask yourself if 2hp is worth the headache of the cel when youll most likely have to swap out the test pipe everytime emissions is due. just giving advice based on my experience. hope whatever you decide on works out.

 

Can you link me to this high flow cat

 

my mistake on the price. it is actually about $80. hope that wont change your mind. and i dont work for magnaflow or anything lol. its just the one that i have and that a lot of people recommend.

http://www.amazon.com/gp/aw/d/B000COTIRK

also if youre replacing the cat back piping with 2.5, you should consider at least doing the one ball mod (removing the resonator and replacing with 2.5 piping to the muffler), unless youre replacing the muffler as well. my cuurent setup is: megan race header, into 2.5 magnaflow cat, into 2.5 piping routed passenger side of the battery, into a tiny little cherry bomb muffler (which is like 10"x10" and cost around $45 with 2.5 in/out), out the back of the car with a 5" tip.

 

Not bad at all....Jown, I'll be making my own exhaust out of 2.5" titanium but if i do end up getting this car im going to have to weld 2 vband flanges onto it AND 2 vband flanges on my exhaust...if i go that route then i might just make a test pipe and weld 2 vband flanges on that as well and when inspection time comes around ill just swap in the cat...

This is of course if the o2 trick doesnt work then ill be going that route.

 

im rocking the P0420 code now too :(
its funny, i had my o2 unplugged for a week or more waiting to get my exhaust finished (driving with open headers) and NO cel light... get exhaust installed, slap in o2, and a week later, BAM! cel light!

im half tempted to just unplug the damn thing from the exhaust, zip tie it somewhere, and use a bung plug, see if she throws a code. otherwise, im going to try and drill out 2 spark plug defoulers, stack them to be used as the o2 spacer.

there is an electrical o2 simulator for minis, but its like $40, just an FYI...

 

Look into the longevity of aftermarket cats. There's a reason they're $80 compared to $800 from a dealer.

 

TheBigChill, you have a point there thats why like i said that will be plan B (if the o2 sensor spacer does not work) and if i do end up getting the CAT then it will ONLY go on right before inspection

 

I run that "adjustable" Vibrant spacer, and it's been working beautifully for 8 months (just got the car inspected today, actually). Good luck.

 

I have been running the Magna Flow cat for several years, Don't let anyone fool you after a little age it will throw the 420 code. I don't have smog testing so it doesn't bother me. I just reset it and it may stay off for a week or it may stay off for a hour. I plan to play around with depth of the 02 sensor it the pipe, Some of the supercharged Cobalt guys have the same problem and that is how they over come the problem.