technical N55 Soot on rear bumper. Running Rich Or Normal?

[Liam H]

So before i sorted out the issue i had with my car with the engine running lean and excessive grey smoke out the exhaust, i had quite a lot of Soot on the rear bumper. Fast forward to now, and all is well. I cleaned the MAP sensor which was full of oil and the car is running great and smooth. So far as I can see. the car stopped smoking, or atleast much less. However, I seem to have still a bit of soot on the exhaust on the rear bumper and around the exhaust. My question is, is this normal for a tuned n55 to gather some soot on the rear of the car? It is not as bad as it use to be before i fixed the car but it still seems to leave a bit of soot, but im guessing its from running a little bit rich because the car is tuned. Just want to know some opinions. The car might have always had the soot and I never realized it perhaps.

Pictures below

(wanted to post in the 335i chat but does not allow me to attach images)

F30 335i n55 pwg

 

[Peter@AEW]

Soot is a sign of higher than normal oil consumption caused by stem seals worn rings or too rich a mixture.

 

[Liam H]

Soot is a sign of higher than normal oil consumption caused by stem seals worn rings or too rich a mixture.

Could it also be from turbo seals?