Quote:
Originally Posted by BlakeBehrens
Looking to get a DP for my 2019 440i, what are some of the pros and cons between the catless/catted downpipes? Or is there virtually no performance difference? New to all this and appreciate any input  |
Catless: makes your car stink like unburnt fuel and you will get a O2 CEL unless you run a tune to disable that check or put in a O2 simulator for the bottom O2 sensor. Exhaust note sounds tinny and harsh.
Catted (high flow): Good ones won't trigger the CEL, and have marginally less performance than catless. Stick to catted downpipes with the 4" catalyst vs those bragging 5" on a 4" downpipe. The 5" versions will give the CEL, and sound horrible (boomy raspy sound).