Sound like surging?

andyho123 · 12-13-2013, 07:28 PM

Weird sound when the bov vent. Idk if it sound like a light surge

Freon · 12-13-2013, 08:04 PM

I just hear an aftermarket blow off valve of some sort operating normally.

That rpm dependent whine a moment after is odd to me.

andyho123 · 12-13-2013, 08:06 PM

Yeah the moment right when it vented out. The sound is kinda like like surging

Cozy · 12-20-2013, 08:19 AM

Surge is when pressurised air is forced back into the compressor housing the wrong way i.e. FMIC hot side and causes the compressor wheel to chop the air, making a rapid 'chuff chuff chuff' sound. This is a situation only produced under load and while 'on boost' caused by a build up of air in the intake system. For example if your turbo is drawing in more air than an inefficient FMIC can flow or the mapping of an engine is willing to combust it'll get built up. BOV surge, as it is called, or to give it another name, turbo flutter, is along the same lines as above where by air is returning to the compressor wheel but this is caused by a bov spring that's too stiff for the level of pressure that the turbo is producing, therefore it cannot open fully and cannot vent the air.

Your video shows signs of neither

12-13-2013, 07:28 PM	#1
andyho123 First Lieutenant 54 Rep 382 Posts Drives: 2015 Yas Marina Blue M4 Join Date: Aug 2013 Location: DALLAS, TX iTrader: (1)	Sound like surging? Weird sound when the bov vent. Idk if it sound like a light surge
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12-13-2013, 08:04 PM	#2
Freon Major 81 Rep 1,051 Posts Drives: 2009 135i Join Date: Nov 2007 Location: Indianapolis iTrader: (3)	I just hear an aftermarket blow off valve of some sort operating normally. That rpm dependent whine a moment after is odd to me. __________________ 2009 BMW 135i 6MT Sport, AFE intake, Cobb AP, Apex 18x8.5+9.5, 255/275 PSS
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12-13-2013, 08:06 PM	#3
andyho123 First Lieutenant 54 Rep 382 Posts Drives: 2015 Yas Marina Blue M4 Join Date: Aug 2013 Location: DALLAS, TX iTrader: (1)	Yeah the moment right when it vented out. The sound is kinda like like surging
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12-20-2013, 08:19 AM	#4
Cozy Major 111 Rep 1,487 Posts Drives: E82 135i Join Date: Mar 2011 Location: Surrey, England iTrader: (0)	Surge is when pressurised air is forced back into the compressor housing the wrong way i.e. FMIC hot side and causes the compressor wheel to chop the air, making a rapid 'chuff chuff chuff' sound. This is a situation only produced under load and while 'on boost' caused by a build up of air in the intake system. For example if your turbo is drawing in more air than an inefficient FMIC can flow or the mapping of an engine is willing to combust it'll get built up. BOV surge, as it is called, or to give it another name, turbo flutter, is along the same lines as above where by air is returning to the compressor wheel but this is caused by a bov spring that's too stiff for the level of pressure that the turbo is producing, therefore it cannot open fully and cannot vent the air. Your video shows signs of neither
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