Stoichiometric (afr of ~14.7:1) gasoline burning will be very much soot free. These cars run near stoich on gentle driving, sometimes even ultra lean burn for efficiency.
BUT, when you use full throttle, the 335i goes rich to about 11.5:1 to keep exhaust temps lower, to protect your turbo and catalytic. Running it slightly rich reduces the power (compared to stoichiometric for that air amount), and creates some minor soot due to some fuel not being fully burned.
If you have some soot, it may indicate you are driving the car hard often.
It's all perfectly normal as long as you don't have check engine on and/or failure of components.
-Abel
- E36 328is ~210-220whp: Lots of Mods.
- 2000 Z3: Many Mods.
- 2003 VW Jetta TDI Manual 47-50mpg
- 1999 S52 Estoril M Coupe
- 2014 328d Wagon, self-tuned, 270hp/430ft-lbs
- 2019 M2 Competition, self-tuned, 504whp
- 2016 Mini Cooper S
Bookmarks