What's causing this NOISE?? (Video attached)

kawalaser · 08-23-2015, 08:36 AM

It's a loud chirp that seemed BOV related, but I just finished removing, cleaning, and lubricating the piston and o-rings on my TIAL 50mm BOV. Vacuum host to BOV is clamped, no noticeable kinks or anything like that.

Car is FBO Cobb Stage 2+... this noise started a few weeks ago and happens only when I'm really getting on it. Car seems to hold boost just fine, but letting off WOT causes it to make this noise.

kawalaser · 08-29-2015, 06:26 AM

no ideas?

all4bspinnin · 08-29-2015, 02:48 PM

Sounds like your bypass valve

thatoneguy... · 08-29-2015, 08:32 PM

You might want to check your vacuum line. I know that this is a piston type BOV as opposed to flange type, but I'll be damned if it doesn't sound like my old A4's did when it went. Are the piston's springs calibrated properly for the boost level?

kawalaser · 08-30-2015, 08:28 AM

thanks for the replies. The sound came on suddenly after using this setup after approx 5,000 miles, leading me to think it's not the spring. The spring is the 11lb one recommended for these cars.

The vacuum line appears OK.

This is a video of the BOV in operation.

kawalaser · 09-07-2015, 05:16 AM

Bumping. Just returned from a German mechanic who actually turned me away because he thought it would be a fishing expedition to chase down this noise. I guess I'll put it on the lift, remove the bumped and check all of the hoses to/from the intercooler. What a pain in the ass.

08-23-2015, 08:36 AM	#1
kawalaser New Member 2 Rep 6 Posts Drives: 08 135i M-Sport 6MT Sedona Join Date: Dec 2012 Location: Ramstein, Germany iTrader: (0)	What's causing this NOISE?? (Video attached) It's a loud chirp that seemed BOV related, but I just finished removing, cleaning, and lubricating the piston and o-rings on my TIAL 50mm BOV. Vacuum host to BOV is clamped, no noticeable kinks or anything like that. Car is FBO Cobb Stage 2+... this noise started a few weeks ago and happens only when I'm really getting on it. Car seems to hold boost just fine, but letting off WOT causes it to make this noise.
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08-29-2015, 06:26 AM	#2
kawalaser New Member 2 Rep 6 Posts Drives: 08 135i M-Sport 6MT Sedona Join Date: Dec 2012 Location: Ramstein, Germany iTrader: (0)	no ideas?
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08-29-2015, 02:48 PM	#3
all4bspinnin Second Lieutenant 38 Rep 206 Posts Drives: 09 135i LeMans Blue/Terracota Join Date: May 2015 Location: Jax, FL iTrader: (0)	Sounds like your bypass valve
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08-29-2015, 08:32 PM	#4
thatoneguy... Private 26 Rep 62 Posts Drives: '09 135i Join Date: Aug 2015 Location: 3rd Rock from the Sun iTrader: (1)	You might want to check your vacuum line. I know that this is a piston type BOV as opposed to flange type, but I'll be damned if it doesn't sound like my old A4's did when it went. Are the piston's springs calibrated properly for the boost level?
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08-30-2015, 08:28 AM	#5
kawalaser New Member 2 Rep 6 Posts Drives: 08 135i M-Sport 6MT Sedona Join Date: Dec 2012 Location: Ramstein, Germany iTrader: (0)	thanks for the replies. The sound came on suddenly after using this setup after approx 5,000 miles, leading me to think it's not the spring. The spring is the 11lb one recommended for these cars. The vacuum line appears OK. This is a video of the BOV in operation.
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09-07-2015, 05:16 AM	#6
kawalaser New Member 2 Rep 6 Posts Drives: 08 135i M-Sport 6MT Sedona Join Date: Dec 2012 Location: Ramstein, Germany iTrader: (0)	Bumping. Just returned from a German mechanic who actually turned me away because he thought it would be a fishing expedition to chase down this noise. I guess I'll put it on the lift, remove the bumped and check all of the hoses to/from the intercooler. What a pain in the ass.
	Appreciate 0 Quote