Downpipe and O2 Sensor

[Mo95Talon]

I was thinking of purchasing an Apexi GT downpipe for my TSi, but I am worried about the O2 sensor after the cat. Since the Apexi eliminates the cat, will it interrupt proper O2 reading?

 

[zippyshoe]

You will probably get a CEL without a cat. The ECU compares the readings between the pre-cat and post-cat O2 sensors in order to monitor the performance of the cat. Hence, the ECU will sense that there is a problem with the cat (or lack thereof) and generate a CEL.

 

[Mo95Talon]

Will this modify anything having to do with engine performance? Will this hurt anything? Is there a fix to this problem? Thank you.

 

[zippyshoe]

This should not affect anything related to engine performance or driveability. Here is a site I found that discusses a method of "tricking" the ECU if you are catless: http://www.vfaq.com/mods/O2bypass.html . Another option you might consider if you are concerned at all about emissions is to purchase a non-cat-eliminating downpipe and a high-flow cat. Hope this help.

 

[Mo95Talon]

Thank you for all of the information and the link. I appreciate it greatly. Take care now.