Hey guys! Looking to get some info on rear o2 sensors, and test pipes.

So I recently bought a Megan Racing header + test pipe for my 2003 MCS, and use it for local track days. Sadly they require no CEL to run on said track days, so my biggest concern is rear o2 code going off due to being catless.

So my question really is, Has anyone done a catless setup on their mini, and got around throwing rear o2 codes. Is there some tuner you can get to get rid of the code? Little extra info, the header + test pipe did come with a 90 degree o2 spacer.

 

If that spacer doesn't work, buy 2 spark plug foul preventers, drill one out on the end so it's just a tube all the way through, then screw that into the non modified one, then install in exhaust and put the sensor in that. I've done that a ton of times on friends and personal vehicles, has worked every time for me. (Disclaimer, never done on mini but don't see why it wouldn't work)

 

I will be following this as we are installing a Megan header this weekend. I have purchased an o2 simulator from big daddies garage, will find out this weekend.....if all of the parts arrive. Including power steering reservoir hoses that are leaking.

 

The simulators and spacers don't work, you'll have a light. Even properly working aftermarket headers leave you open to oxygen sensor codes due to their lower cell count and size.

No need to remove the cat for track days, or daily driving for that matter. I'd say just leave the cat in place and not worry too much about a CEL.

Your only true option would be to tune the car and have your tuner program out the post cat O2.