[beppeM3+123d]

I recently installed catted fi exhaust 200 cell downpipe, car is ok, bo cell, sound is great.

Make several diagnose with ista and no warning light at all.

I would like to ask to most experienced guys if there is any risk of damage due to the changed stechiometric ratio, more air for sure and does the dme but more fuel??

Thanks for the help!

[mr_lab_rat]

No risk at all other than throwing a CEL for cat efficiency.

The main oxygen sensor is before the cat. That's the one used for controlling fuel mixture.
Only the secondary sensor is affected by the aftermarket downpipe. Its primary function is to monitor if your catalytic converter is working correctly.

[beppeM3+123d]

Originally Posted by mr_lab_rat

No risk at all other than throwing a CEL for cat efficiency.

The main oxygen sensor is before the cat. That's the one used for controlling fuel mixture.
Only the secondary sensor is affected by the aftermarket downpipe. Its primary function is to monitor if your catalytic converter is working correctly.

Thank you sir! So the first sensor read more air and adapt dme to give more fuel? Correct?

[mike@x-ph.com]

No risk, enjoy

[VisualEcho]

Originally Posted by beppeM3+123d

Thank you sir! So the first sensor read more air and adapt dme to give more fuel? Correct?

Yes.

[Happy Motoring]

I've had the same dp for thousands of miles with no cel. I am running BM3 though and flash to stock once a year for my emissions which is no problem.