[mtreeforty]

Hey, I have a 2020 m340 and after putting my catless down pipe on I’m experiencing a very minimal smell inside the cabin through the vents with ac on every time I come to a stop or at idle( all windows rolled up), is this normal or could this be a problem?

[HFW003]

You will have smell with catless DP!

[Matic94]

Is your AC on fresh air or recirculating? I have personally never used fresh air in this car while catless, but with the windows rolled up while using recirculating, I never smell anything.

[mtreeforty]

It doesn’t smell with recirculation on but during the winter time when I have the heat on the recirculation turns off by itself all the time and that’s when I start smelling it at lights