I just had a Techart exhaust system installed and my check engine light is now lit. From what I've read, it's fairly common to get an O2 CEL with this exhaust. What are folks using for O2 spacers? I'm assuming that'll help?

 

It must be 100 cell cats or catless system?
FVD and SpeedTech sells them to help with that problem.
Good Luck

 

think mine is from Vibrant. Milltek exhaust. No CEL but not sure if its needed anyway...

 

Get a tune. They remove that regardless. Plus it's more fun.

 

not sure if OP is tuned or not, but I am(and am re-tuning with EPL). Simpler to pass emissions with a extended O2 than by bypassing the readiness code

 

How do the spacers affect the output of the O2 sensors? I'm considering doing the stock muffler mod that creates a short circuit through the muffler internally with the 2 inch cut out as described in the forums here but don't want to deal with the emissions repercussions. Would the spacers correct emissions failure after the muffler mod is performed? Like to understand the physics behind how the spacers are supposedly working.

 

the extenders keep the secondary O2's out of the exhaust stream and in a 'clean' air space. Not needed for muffler modifcations, only if removing or using certain high-flow catalytic converters.
I'm going to try removing them this year and see if I get a CEL...

 

https://www.fabspeed.com/universal-9...nverters-pair/

just can't understand how does this little cat get enough of the main exhaust flow to heat-up sufficiently for the cat to actually function ?and gases has to flow out through cat and here they end up into O2 sensor.....

 

I'm running 3.5" catless bypass pipes and using the short FVD extenders as you can see on the 3rd rearmost oxygen sensor below. Works as advertised. No CEL and all readiness codes show as READY.

 

Yours is not cheap extender, it is the same type 'minicat' as from Fabspeed
https://www.fvd.net/us-en/FVD111LAMS...r-minicat.html

I'm started thinking do I really need these minicats as I will have engine ECU custom tune up

 

x2. I tried the spacer route pre-tune; never lasted.