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      11-10-2012, 11:00 AM   #31
HighlandPete
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Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

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I'd say it is simply caused by a wet exhaust. Are you guys doing lots of shortish trips? Exhaust systems not completely drying out.

I've noted on my 535i that the exhaust shows more black soot that what I was used to seeing, when I had my last BMW petrol engine. In fact more soot at the exhaust tip than my BMW diesel with DPF fitted. Plus there is lots more condensation from this engine than expected, and for a longer period on warm up.

I've read that the 'sooting' in the exhaust tips is a trait of the DI engines. If it is and we have condensation, it will blow it out, where it sticks will depend to a degree on the speed it comes out and how wet.

HighlandPete
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