# O2 Sensor Spacer Questions



## cjb88 (Aug 21, 2010)

Well I have searched and I see that lots of people use them for high flow cats. A few people use them with catless downpipes. Well I am considering installing the 3" Catless DP I just ordered used off here as it is instead of adding a cat to it. Those of you running catless with a spacer and NO tuning, were you successful in eliminating the CEL? As well which one are you using? 42DD? 034 Motorsports? BFI? 

Thanks for the help guys!!


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## sponcar (Feb 5, 2010)

hmmm Im running a 3" catless dp with giac tune. I decided to run a spacer because i didnt want to burn my 02sensor while sitting half way into the pipe. It won't be 100% sure that you wont to have the cel but defintly it will help. I have deal with the intermitent cel for not running a cat but it doesnt affect perfomance at all.


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## MÄDDNESSS (Oct 18, 2010)

i hav a FT on the way with a 3" DP. i need to put spacers under the 02 Sensors?

just any spacer? or does it need to be a certain thickness?


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## The*Fall*Guy (Aug 10, 2009)

Order the angled o2 spacer from bfi :thumbup:


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## cjb88 (Aug 21, 2010)

The*Fall*Guy said:


> Order the angled o2 spacer from bfi :thumbup:


This the spacer you I running then I am guessing? If so, how long have you run it like that without tuning for rear O2 elimination? Just trying to figure this thing out. I really am not interested in have a check engine light that comes on randomly because of one of my mods....


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## MÄDDNESSS (Oct 18, 2010)

The*Fall*Guy said:


> Order the angled o2 spacer from bfi :thumbup:


awsome thanks.:thumbup:


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## highvelocitygti (Aug 28, 2006)

I'm running without a cat with a spacer. I think thats the best set up. No CEL.


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## MÄDDNESSS (Oct 18, 2010)

highvelocitygti said:


> I'm running without a cat with a spacer. I think thats the best set up. No CEL.


good to hear. 

did you get the 02 spacer/elbow thingy from BFI?

did you get it for both. or just 1 of the 2? if so, which 1?


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## cjb88 (Aug 21, 2010)

You only have to run a spacer on the rear sensor. So you guys prefer the BFI one to the 42dd one? or to any others available?


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## MÄDDNESSS (Oct 18, 2010)

"1965truckrod" from socaleuro told me i only need to run it on the 1st sensor.
and he sent me this link for the spacer he runs. he loves it.
and i guess the BFI sensor rubs against something.
this 1 doesnt.
i JUST orderd it.
check it out for your self.


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## MÄDDNESSS (Oct 18, 2010)

this is what he sent me.

_This is the one I am using: http://www.raimotorsport.com/RAI-J-P...p/11620vib.htm It is nice because it keeps the O2 sensor from rubbing against the chassis. You only need the spacer for the forward sensor the rear sensor really doesn't have much that is concerning for the tune or CEL's.

Jesse _


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## The*Fall*Guy (Aug 10, 2009)

No.. You use it on the rear (post catalyst o2 sensor.. The purpose of the spacer is to fool the computer into thinking the cat is still there. 

Obviously the pre cat readings arent going to change without the cat.

Spacing the pre cat o2 will cause BIG problems


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## MÄDDNESSS (Oct 18, 2010)

highvelocitygti said:


> I'm running without a cat with a spacer. I think thats the best set up. No CEL.


do you hav it on the 1st or 2nd 02Sensor?


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## MÄDDNESSS (Oct 18, 2010)

The*Fall*Guy said:


> No.. You use it on the rear (post catalyst o2 sensor.. The purpose of the spacer is to fool the computer into thinking the cat is still there.
> 
> Obviously the pre cat readings arent going to change without the cat.
> 
> Spacing the pre cat o2 will cause BIG problems


your running a spacer on the 2nd 02Sensor?


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## MÄDDNESSS (Oct 18, 2010)

what do you mean "post" 02Sensor?

the 1st 02 in my exhaust is before the cat.
the 2nd 02 is in the middle of the cat.


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## The*Fall*Guy (Aug 10, 2009)

The second o2 AFTER the cat is where you want it:thumbup:

The purpose of the 2nd o2 is to test catalyst function.. Hence why you space it

The purpose of the first o2 is to provide ACCURATE a/f readings to your ecu.. Hence why youde NEVER want to space it...


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## The*Fall*Guy (Aug 10, 2009)

Oh.. And aim the angled part of the spacer towards the front of the car..


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## ejg3855 (Sep 23, 2004)

Spark Plug Foulers from FLAPS are way cheaper than the BFi or 42 parts and do the same thing.

They go on the 2nd 02 sensor if you have one on the primary you are stupid and please don't work on your car.


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## The*Fall*Guy (Aug 10, 2009)

Yes they are cheaper.. They also put the o2 in a bad position, and because they dont angle the sensor away from the exhaust flow, they are hit, and miss with regards to accomplishing the task. 

I dont see $30 +- a big investment :screwy:


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## MÄDDNESSS (Oct 18, 2010)

The*Fall*Guy said:


> The second o2 AFTER the cat is where you want it:thumbup:
> 
> The purpose of the 2nd o2 is to test catalyst function.. Hence why you space it
> 
> The purpose of the first o2 is to provide ACCURATE a/f readings to your ecu.. Hence why youde NEVER want to space it...


i dont hav an 02 after the cat.
just 1 before it. and 1 in the middle of it.


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## MÄDDNESSS (Oct 18, 2010)

The*Fall*Guy said:


> Oh.. And aim the angled part of the spacer towards the front of the car..


why towards the front?


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## MÄDDNESSS (Oct 18, 2010)

MÄDDNESSS said:


> i dont hav an 02 after the cat.
> just 1 before it. and 1 in the middle of it.


ps: this is on the exhaust that on it now.
idk where the 02 sensors go on the exhaust im getting.


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## The*Fall*Guy (Aug 10, 2009)

Thats not the middle of the cat bozo :facepalm:

Just put the spacer on the second ****ing o2, and get on with your life..

More wrenching > More posting :screwy:

Your question(s) have been answered...

And spray the ****ing things down with a ton of pb blaster the night before install.. Ditto for the downpipe bolts, etc..

Now gtfo


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## ejg3855 (Sep 23, 2004)

The*Fall*Guy said:


> I dont see $30 +- a big investment :screwy:


Its not, I personally made on on a mill but not everyone has access to a mill. Not everyone has an extra $30 when there is a $3 solution.

Just giving options.



The*Fall*Guy said:


> More wrenching > More posting :screwy:
> 
> Your question(s) have been answered...


Exactly. search, search, google search, post. So annoying to answer the same questions once a month for years.


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## DMVDUB (Jan 11, 2010)

Just a side note, you're best option is to get SW with the second O2 cel removed... 

I've run the 42DD spacer and it didn't help (at first). It did help when I ran the spacer and leaned it out about 5-10% though, overly rich tune I guess

Oh, and for the cheapo people here's the EVO guy's version of the spacer. 2x Plug Non-Fouler's and a drill.


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## 20vturbslo (Feb 26, 2010)

Ive been running this angle type spacer with the 02 sensor parallel with the pipe facing towards the front. Has worked great so far with no cat and SAI deleted. maybe once a month ill get an improper flow code. (Stock tune)

ebaymotors / Oxygen-SENSOR-ANGLE-ADAPTER


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## NCdub91 (Aug 16, 2010)

I've had the BFI spacer on for about two months now and no CEL, and it's a catless downpipe. But all cars are not the same so you might throw a code.


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## MÄDDNESSS (Oct 18, 2010)

The*Fall*Guy said:


> Thats not the middle of the cat bozo :facepalm:QUOTE]
> 
> correct me if im wrong but is this not the middle of the CAT


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## 20vturbslo (Feb 26, 2010)

MÄDDNESSS said:


> The*Fall*Guy said:
> 
> 
> > Thats not the middle of the cat bozo :facepalm:QUOTE]
> ...


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## cjb88 (Aug 21, 2010)

Well I ordered the spacer from BFI. Should get it on Thursday and installing the 3" catless downpipe and 2.5" GHL catback on Saturday! I am seriously excited. Hopefully the spacer keeps the CEL off.


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## MÄDDNESSS (Oct 18, 2010)

i got a spacer from another company and i cant thread it on my 3" or my stock 1. :banghead::banghead:

im gonna hav to either weld in a new bunion to the 3" or get the spacer from BFI.


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## OpenYourSoul610 (Sep 11, 2013)

cjb88 said:


> Well I ordered the spacer from BFI. Should get it on Thursday and installing the 3" catless downpipe and 2.5" GHL catback on Saturday! I am seriously excited. Hopefully the spacer keeps the CEL off.


:thumbup: but did it work? what company down pipe is it?


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## cjb88 (Aug 21, 2010)

I completely forgot about this thread! And yes, I haven't had a single CEL since I installed the exhaust. BFI spacer works awesome!


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## 19jetta91 (Apr 26, 2006)

I've been running a 3in eBay down pipe without a cat and a Wayne angle block on the SECOND o2 sensor for 4 years now without any problems.


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