O2 defouler/spacer long term review

lixiang7349 · 08-21-2021, 06:38 PM

I have the CTS catted DP and the CEL came on not too long after installation.
Gotta get this thing pass emission in OR.

Questions:
1. do spacers work long term?
2. which one (please attach links) has been proven to work well?
3. anything else I should know before going this route?
4. I only need to install the spacer for A (in the pic), NOT B right?
5. Do I have to take the downpipe down or is it a pretty simple add?

Thank you!

Hiflyer731 · 08-22-2021, 09:49 AM

The 90 degree spacer fits well and a lot of them come with a tiny catalyst in them. They are not vehicle specific and a quick Google search turns up quite a few. I think fabspeed sells one for a couple hundred dollars but it appears to have the biggest mini catalyst, although they don't claim to be CEL free. It is for the O2 sensor after the cat which only monitors the cat efficiency. I really think it's hit or miss with these but a 90 deg with mini cat is probably your best bet.

dmanb2b · 08-22-2021, 05:20 PM

Sell it and replace with an AA catted DP

about94ninjas · 08-25-2021, 10:24 AM

I just grabbed a pack of O2 spacers from autozone (think they're called something else for legal reasons), stacked them together and I haven't had a CEL for over a year

vektorprime · 09-24-2021, 09:16 AM

Isn't the O2 sensor in the DP used for AFR calculations and other things? I suspect using a spacer may cause bad data to be fed back the ECU.

Hiflyer731 · 09-24-2021, 09:22 AM

The post cat O2 sensor lives only to taddle on you. It doesn't have anything to do with engine management.

Info@mad-us.com · 09-27-2021, 08:12 PM

Don't think it will work well on these newer cars unfortunately

Jnat · 10-10-2021, 08:20 AM

i'm running the CTS catted and used a small spacer on 02 sensor #2/rear/ in your illustration A and i have no MIL but more importantly have satisfied readiness which is the key in my state for inspection...

lixiang7349 · 10-10-2021, 08:35 AM

Quote:

Originally Posted by Jnat

i'm running the CTS catted and used a small spacer on 02 sensor #2/rear/ in your illustration A and i have no MIL but more importantly have satisfied readiness which is the key in my state for inspection...

Are you stage2 or 2+?
I'm 2+ and I have 3 incomplete (INC) showing up. Fuel is due to the tu hpfp I guess but it's "OEM" supposedly. Was hoping to not run into this issue. The other 2 are cat related I'm guessing

mike082802 · 10-10-2021, 02:05 PM

i have cts catted and tu pump on bm3 with O2 spacer, i could never get readiness unless i flashed back to stock. it was driving me nuts, fuel system and cats were never ready.

Jnat · 10-12-2021, 05:27 PM

Quote:

Originally Posted by lixiang7349

Are you stage2 or 2+?
I'm 2+ and I have 3 incomplete (INC) showing up. Fuel is due to the tu hpfp I guess but it's "OEM" supposedly. Was hoping to not run into this issue. The other 2 are cat related I'm guessing

Basic Stage 2 not +, i'm thinking of the TU upgrade (just not sure i need to take it that far, still deciding). I was surprised also when readiness was set... note the following - i normally run the stage 2 95 map (achieved with the use of E85) and readiness did not set, i switched for the heck of it to the E30 map and that's when all the monitors were set...

Curious question is::: Do you have factory cat or aftermarket cat checked off in options? I have factory cat checked...

Edit, just checked, set readiness with the 95 map also...

leew102 · 10-12-2021, 05:58 PM

Quote:

Originally Posted by mike082802

i have cts catted and tu pump on bm3 with O2 spacer, i could never get readiness unless i flashed back to stock. it was driving me nuts, fuel system and cats were never ready.

Did you turn the cat monitors back to oem in the settings?

Jnat · 10-12-2021, 06:21 PM

Quote:

Originally Posted by leew102

Did you turn the cat monitors back to oem in the settings?

Yes...

mike082802 · 10-12-2021, 07:04 PM

Quote:

Originally Posted by leew102

Did you turn the cat monitors back to oem in the settings?

i flashed back to stock so yes they were on

leew102 · 10-13-2021, 12:38 AM

Quote:

Originally Posted by Jnat

Quote:

Originally Posted by leew102

Did you turn the cat monitors back to oem in the settings?

Yes...

Quote:

Originally Posted by mike082802

Quote:

Originally Posted by leew102

Did you turn the cat monitors back to oem in the settings?

i flashed back to stock so yes they were on

Was more so asking Mike. I plan on using a spacer to try passing inspection, but would like to keep stage 2 on, just with cat monitors turned on. So wanted to see if Mike, you were having issues getting readiness to show with stage 2 and cat monitoring turned on.

mike082802 · 10-13-2021, 03:57 AM

Quote:

Originally Posted by leew102

Was more so asking Mike. I plan on using a spacer to try passing inspection, but would like to keep stage 2 on, just with cat monitors turned on. So wanted to see if Mike, you were having issues getting readiness to show with stage 2 and cat monitoring turned on.

i had problems trying to pass on stage 2, fuel system was never ready and either were cat monitors even though i turned them on. i banged my head for a while and finally someone suggested to flash to stock, after that i was ready, all monitors. never had an issue on my n54 with leaving my custom tune and catless dp, i would just have 1 monitor not ready which is ok in NY.

leew102 · 10-13-2021, 08:10 AM

Quote:

Originally Posted by mike082802

Quote:

Originally Posted by leew102

Was more so asking Mike. I plan on using a spacer to try passing inspection, but would like to keep stage 2 on, just with cat monitors turned on. So wanted to see if Mike, you were having issues getting readiness to show with stage 2 and cat monitoring turned on.

i had problems trying to pass on stage 2, fuel system was never ready and either were cat monitors even though i turned them on. i banged my head for a while and finally someone suggested to flash to stock, after that i was ready, all monitors. never had an issue on my n54 with leaving my custom tune and catless dp, i would just have 1 monitor not ready which is ok in NY.

Do you happen to have the link to the spacer you use?

dmanb2b · 10-13-2021, 05:36 PM

I have no issues with readiness on bm3 2.0, but I am running an aa catted dp and stock hpfp. All monitors are ready.

mike082802 · 10-13-2021, 07:45 PM

Quote:

Originally Posted by leew102

Do you happen to have the link to the spacer you use?

i do not, came on the dp when i bought it. looks like a straight 2" spacer.

Dav340 · 04-17-2023, 05:18 PM

Hey I am having the same trouble with passing Inspection and am tired of wasting money and time switching back to stock downpipe. Which o2 sensor spacer would I be able to try to get passed inspection. I have CTS high flow catted down pipe.

Jnat · 04-17-2023, 05:24 PM

Quote:

Originally Posted by Dav340

Hey I am having the same trouble with passing Inspection and am tired of wasting money and time switching back to stock downpipe. Which o2 sensor spacer would I be able to try to get passed inspection. I have CTS high flow catted down pipe.

small spacer on sensor 2
btw, with this spacer on my kittyless downpipe all monitors set, i can't explain it...

Dav340 · 04-17-2023, 05:28 PM

Facts do you know which spacer you had ?

08-21-2021, 06:38 PM	#1
lixiang7349 Lieutenant 284 Rep 487 Posts Drives: customE50Tune Join Date: Apr 2019 Location: N/A iTrader: (0)	I have the CTS catted DP and the CEL came on not too long after installation. Gotta get this thing pass emission in OR. Questions: 1. do spacers work long term? 2. which one (please attach links) has been proven to work well? 3. anything else I should know before going this route? 4. I only need to install the spacer for A (in the pic), NOT B right? 5. Do I have to take the downpipe down or is it a pretty simple add? Thank you! Attached Images
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08-22-2021, 05:20 PM	#3
dmanb2b Banned 2125 Rep 3,368 Posts Drives: G07, F97, F30, E90, E46, E30 Join Date: Jul 2016 Location: NY iTrader: (5)	Sell it and replace with an AA catted DP
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08-25-2021, 10:24 AM	#4
about94ninjas Private First Class 95 Rep 116 Posts Drives: ‘18 340i Join Date: Oct 2018 Location: Fresno, CA iTrader: (1)	I just grabbed a pack of O2 spacers from autozone (think they're called something else for legal reasons), stacked them together and I haven't had a CEL for over a year
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09-24-2021, 09:16 AM	#5
vektorprime Private First Class 43 Rep 148 Posts Drives: 440xi Join Date: Dec 2014 Location: United States iTrader: (0)	Isn't the O2 sensor in the DP used for AFR calculations and other things? I suspect using a spacer may cause bad data to be fed back the ECU.
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09-24-2021, 09:22 AM	#6
Hiflyer731 Private 24 Rep 85 Posts Drives: 2016 340i Join Date: Dec 2018 Location: Southern California iTrader: (0)	The post cat O2 sensor lives only to taddle on you. It doesn't have anything to do with engine management.
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08-22-2021, 09:49 AM	#2
Hiflyer731 Private 24 Rep 85 Posts Drives: 2016 340i Join Date: Dec 2018 Location: Southern California iTrader: (0)	The 90 degree spacer fits well and a lot of them come with a tiny catalyst in them. They are not vehicle specific and a quick Google search turns up quite a few. I think fabspeed sells one for a couple hundred dollars but it appears to have the biggest mini catalyst, although they don't claim to be CEL free. It is for the O2 sensor after the cat which only monitors the cat efficiency. I really think it's hit or miss with these but a 90 deg with mini cat is probably your best bet.
	Appreciate 1 lixiang7349283.50 Quote

09-27-2021, 08:12 PM	#7
Info@mad-us.com BimmerPost Supporting Vendor 1910 Rep 4,902 Posts Drives: bmw Join Date: Mar 2021 Location: Mad-us.com iTrader: (0)	Don't think it will work well on these newer cars unfortunately __________________ - Click Here Performance Parts For Your Bmw At Crazy Low Prices! Email: info@mad-us.com
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10-10-2021, 08:20 AM	#8
Jnat DisplacementReplacement 406 Rep 1,100 Posts Drives: 2020 X3M Join Date: Sep 2012 Location: Jersey Shore iTrader: (0)	i'm running the CTS catted and used a small spacer on 02 sensor #2/rear/ in your illustration A and i have no MIL but more importantly have satisfied readiness which is the key in my state for inspection... __________________ 2020 X3M /// MHD Tune Prior Bimmers 2017 240XI Hybrid / FBO / MHD E40 2015 235XI FBO / MHD E30 2009 335XI FBO / COBB / E30
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10-10-2021, 02:05 PM	#10
mike082802 Major 114 Rep 1,004 Posts Drives: 2010 135 Join Date: Feb 2014 Location: ny iTrader: (2)	i have cts catted and tu pump on bm3 with O2 spacer, i could never get readiness unless i flashed back to stock. it was driving me nuts, fuel system and cats were never ready.
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10-13-2021, 05:36 PM	#18
dmanb2b Banned 2125 Rep 3,368 Posts Drives: G07, F97, F30, E90, E46, E30 Join Date: Jul 2016 Location: NY iTrader: (5)	I have no issues with readiness on bm3 2.0, but I am running an aa catted dp and stock hpfp. All monitors are ready.
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04-17-2023, 05:18 PM	#20
Dav340 New Member 7 Rep 20 Posts Drives: BMW 340i xdive msport Join Date: Jul 2020 Location: New York City iTrader: (0)	O2 Sensor spacer Hey I am having the same trouble with passing Inspection and am tired of wasting money and time switching back to stock downpipe. Which o2 sensor spacer would I be able to try to get passed inspection. I have CTS high flow catted down pipe.
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04-17-2023, 05:28 PM	#22
Dav340 New Member 7 Rep 20 Posts Drives: BMW 340i xdive msport Join Date: Jul 2020 Location: New York City iTrader: (0)	Facts do you know which spacer you had ?
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