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      06-10-2011, 09:59 AM   #45
c4s335i
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Drives: 07 335i sedan
Join Date: Oct 2010
Location: Charlotte, NC

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Quote:
Originally Posted by Ulrich View Post
I also have white smoke in my car since I installed catless downpipes, someone had told me the car is running so rich because of the smell and inside the tailpipes there´s a certain kind of black carbon deposits...

Is this problem due to running cattless??
Keep in mind that when you run full catless exhaust there is a risk of more smoke. One reason is there is no filter anymore and any residual smoke from oil/fuel that would usually be burnt up in the cat will now not be. Another is that with reduced back pressure, the turbos tend to blow a little more oil pass their internal seals. Nothing that suggests they are failing, just something that is more common with turbos and open exhausts. If it you're worried about it, throw the cats back on and see if the smoking is less/gone altogether.

Also, white smoke is not just from coolant. Unburnt oil is also a cause for white smoke. For example if you have an intake valve leaking oil into the combustion chamber, or the turbo is leaking oil on the intake charge side of the engine, the oil will be burnt up in the combustion chamber causing it to look blue. However, if the oil is from an exhaust valve, or is leaking purely out of the turbine exhaust seal, that oil will not be burnt up in the combustion chamber and will appear as a white smoke coming out of the exhaust. How much smoke will let you know how bad/serious the issue really is.