M235i FBO Exhaust smoke

james4321 · 11-14-2023, 08:14 AM

Yesterday I have changed the exhaust tips (M Perf Carbon) and before I was not interested so much with my exhaust. 😉
Today I came back, after small city driving, to the garage and reved a bit my car on idle. Went to see my tips and I saw a bit of smoke. Did not check it this way before, so I don’t know for how long it’s smoking. Not much, but visible smoke. When car is idling I can see almost nothing. Need to use flashlight to see just a bit of smoke on idle speed and only from driver side.
I can’t see any smoke when driving. Tips are perfectly clean (old and new), no soot at all.
My car is N55 EWG FBO Catless DP.
Should I worry about that?

SMB_M235i · 11-17-2023, 05:30 AM

I have the same problem whenever im on red light the car emits light smoke. checked my coolant to see if its head gaskets and it turns to be normal. OFHG not leaking VCG also not leaking. I assume its because of the downpipe. but it drives me crazy!

XutvJet · 11-17-2023, 11:01 AM

You are catless. You're seeing fuel vapor and the other emissions that a cat converts into water vapor and generally less harmful emissions. You're not seeing soot because fuel related vapor is largely a solvent.

james4321 · 11-18-2023, 08:00 AM

Quote:

Originally Posted by XutvJet

You are catless. You're seeing fuel vapor and the other emissions that a cat converts into water vapor and generally less harmful emissions. You're not seeing soot because fuel related vapor is largely a solvent.

I did a small investigation, and after a while of driving I can see a bit (not really visible, but could feel on the finger) oily ‚thing’ at the end of exhaust tip. Color of it is bright bronze. That’s strange because when I look in to the exhaust pipe, seems to be dry. Only rear end of exhaust tip (right hand side) is covered with it.

Weird, because there is no bad smoke, so I don’t think it burns the oil…

colin_e90 · 11-21-2023, 02:46 PM

I’ll back up the catless comment. All these symptoms you’re having is because you’re catless. The oily residue is most likely from unfiltered emission’s that’s generally cleaned from the cat. Also the reason why it’s on the right tailpipe only is because that’s the closest exit from the pipe behind the muffler. Assuming you’re on an oem muffler still or m-performance. It also is the side that there is no exhaust flap. The right tailpipe has a very small short chamber to route through in the muffler, where as the left tailpipe goes through an additional chamber and has the flap before it exits out the tip.

11-14-2023, 08:14 AM	#1
james4321 Second Lieutenant 38 Rep 204 Posts Drives: 335i+ Join Date: Mar 2016 Location: Europe iTrader: (0)	M235i FBO Exhaust smoke Yesterday I have changed the exhaust tips (M Perf Carbon) and before I was not interested so much with my exhaust. 😉 Today I came back, after small city driving, to the garage and reved a bit my car on idle. Went to see my tips and I saw a bit of smoke. Did not check it this way before, so I don’t know for how long it’s smoking. Not much, but visible smoke. When car is idling I can see almost nothing. Need to use flashlight to see just a bit of smoke on idle speed and only from driver side. I can’t see any smoke when driving. Tips are perfectly clean (old and new), no soot at all. My car is N55 EWG FBO Catless DP. Should I worry about that?
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11-17-2023, 05:30 AM	#2
SMB_M235i New Member 16 Rep 12 Posts Drives: Estoril Blue M235i Join Date: Aug 2020 Location: MIAMI iTrader: (0)	I have the same problem whenever im on red light the car emits light smoke. checked my coolant to see if its head gaskets and it turns to be normal. OFHG not leaking VCG also not leaking. I assume its because of the downpipe. but it drives me crazy!
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11-17-2023, 11:01 AM	#3
XutvJet Major General 5556 Rep 5,372 Posts Drives: 2011 Cayman Base, 2016 M235 Join Date: Mar 2016 Location: Kansas City iTrader: (-1)	You are catless. You're seeing fuel vapor and the other emissions that a cat converts into water vapor and generally less harmful emissions. You're not seeing soot because fuel related vapor is largely a solvent. __________________ The forest was shrinking, but the Trees kept voting for the Axe, for the Axe was clever and convinced the Trees that because his handle was made of wood, he was one of them.
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11-21-2023, 02:46 PM	#5
colin_e90 First Lieutenant 57 Rep 319 Posts Drives: 2016 M235i Join Date: May 2014 Location: Indio, CA iTrader: (0)	I’ll back up the catless comment. All these symptoms you’re having is because you’re catless. The oily residue is most likely from unfiltered emission’s that’s generally cleaned from the cat. Also the reason why it’s on the right tailpipe only is because that’s the closest exit from the pipe behind the muffler. Assuming you’re on an oem muffler still or m-performance. It also is the side that there is no exhaust flap. The right tailpipe has a very small short chamber to route through in the muffler, where as the left tailpipe goes through an additional chamber and has the flap before it exits out the tip.
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