Why does my exhaust tips have BLACK stains?

[kozmos]

I notice black stains on my lower exhaust tips. My car is stock and has 30,000km. I've also noticed this on all other turbo charged cars ie, cayenne, scoobies, porsche tt etc. I don't have this problem on my 911C4 or my previous car E36 M3.

Seems to me these black stains are found only on turbo charged cars.

Can somebody explain this phenomenon?

[JonnyX]

Do you mean soot? Most exhausts are sooty to some extent. If it's excessive maybe your car
is running rich. I have something similiar at the moment which I am investigating. If you have
VAG-COM check block 32 which gives your lambda probe adaptation values. You will probably
need to search around for some help in interpreting them.

[fade2grey]

I was under the impression turbo cars ran richer (so more muck at the end of the pipe) to keep combusion temps down - I could be wrong though

[Dippy]

You're not wrong. My Miltek tailpipes were silver when installed. Now they are matt black.

[excursion]

It's quite a large capacity engine, the condensation inside the exhaust flushes a lot of soot through to the tailipes. PITA having to clean them all the time.

[S4 OXON]

are there any easy ways of getting it of or just lots of elbow grease

[Pete.S]

Silver cleaner (the sort you get from any supermarket for kitchen use) used to work well on my Cossie stainless steel exhaust; that & a J-cloth and it'll come up like new.....

[excursion]

are there any easy ways of getting it of or just lots of elbow grease

I find a little T-Cut does the trick and brings them up like new