Exhaust Howl / whistle

rhodesman · 04-04-2016, 12:25 PM

I've researched this already but nothing was definitive or answered to my needs so I think this problem is a case-by-case issue and hoping I can solve it with your collective help.

Last week I received my Berk Street Performance Axle back. This has been coupled to my Berk mid-pipes and my AR-DPs w/ racing C.A.T.s (this maybe an important part of this problem).

After about a week of fiddling, adjusting, buying new gaskets, I'm at a loss. When the engine gets in the range of 5k-7k RPMs, I get this wonderful "howl" or "whistle" sound bellowing out from my exhaust. I cannot find the culprit. I've checked the inlets connection to the turbo's, I've adjusted the gaskets at both the DP-midpipe connection and the midpipe-axle back connection and still at 5k-7k, I'm a howling monkey (other, slightly "cooler", name: screaming eagle).

I'm curious if anyone else has had this problem, what you have done to resolve this issue and also, I'm curious if MAYBE the racing C.A.T.s are in someway causing the howl due to the turbulent exhaust coming off the turbines hitting the fins/edges of the C.A.T.s.

I'm seriously considering just buying a pair of BMS DPs just to try that theory, but I rather not throw money at a theory but instead a slightly better confirmed solution. Thoughts?

Thanks!

Yeineken · 04-04-2016, 02:19 PM

I may be incorrect but I believe it's the y-pipe section near the tips. I believe the AFE exhaust also suffered from this problem; considering it had the same design near the tips.

rhodesman · 04-04-2016, 02:54 PM

I was afraid you would say that! I put in a message to Berk but have not heard back. Has anyone running a Berk Street Axle-Back come up with a way to stop this from happening?

TX135i · 04-04-2016, 03:29 PM

Mine does not make the sound you describe, but the exhaust is all stock except for the axle back. It's a 2012 N55.

rhodesman · 04-04-2016, 03:34 PM

Quote:

Originally Posted by TX135i

Mine does not make the sound you describe, but the exhaust is all stock except for the axle back. It's a 2012 N55.

Fascinating, my friend has a 2011 N55 with DPs and Berk Racing Axle-back w/o any problems. I wonder if this a N54 issue?

ShocknAwe · 04-04-2016, 03:40 PM

This is fairly common. Didn't have the issue myself when I had the Berk Street setup, but many others have, and not just with that exhaust.

It's the y pipe split right before the tips. Could be that if we looked inside on noisy units, the welds could be less clean or complete. Just a thought. Also could be very slight variation in distance from the muffler to the y split.

rhodesman · 04-05-2016, 03:12 PM

Well (as-of-now) if I keep the boost under 19psi there is no howl/whistle, I can live with that for the time being.

I was wrong, whistle still there....damn.

I made a call into Berk again and found out all their techs are out for some racing event... hopefully once they are done being a pit-crew, I'll get some answers/course of action.

Solo_M_Tech · 04-06-2016, 05:56 AM

It's the tip design and how close the junction is to the end of the tips. It's the same effect as blowing air across the top of a beer bottle.

My old exhaust did it, so I know what you are describing. Berk should take care of you.

cesarortiz23 · 02-04-2017, 12:44 AM

Quote:

Originally Posted by Uber///M

It's the tip design and how close the junction is to the end of the tips. It's the same effect as blowing air across the top of a beer bottle.

My old exhaust did it, so I know what you are describing. Berk should take care of you.

so what was the fix to this?

or what exhaust does not do this or what set up

thats my fear with modding my exhaust because I don't want that nasty sound.

Solo_M_Tech · 02-04-2017, 09:40 AM

Quote:

Originally Posted by cesarortiz23

Quote:

Originally Posted by Uber///M

It's the tip design and how close the junction is to the end of the tips. It's the same effect as blowing air across the top of a beer bottle.

My old exhaust did it, so I know what you are describing. Berk should take care of you.

so what was the fix to this?

or what exhaust does not do this or what set up

thats my fear with modding my exhaust because I don't want that nasty sound.

The Y split needs to be as far away from the tips as possible. I switched to the Berk race exhaust and the whistle went away.

cesarortiz23 · 02-04-2017, 11:22 PM

Quote:

Originally Posted by Uber///M

The Y split needs to be as far away from the tips as possible. I switched to the Berk race exhaust and the whistle went away.

I've seen some videos of the berk race exhaust and they do it too?

do you have a downpipe on your car?

Solo_M_Tech · 02-05-2017, 08:23 AM

Quote:

Originally Posted by cesarortiz23

Quote:

Originally Posted by Uber///M

The Y split needs to be as far away from the tips as possible. I switched to the Berk race exhaust and the whistle went away.

I've seen some videos of the berk race exhaust and they do it too?

do you have a downpipe on your car?

I don't have the car anymore but it had a catless downpipe with berk midpipes and berk race axleback and it didn't whistle.

2008135i · 02-06-2017, 03:35 PM

I'm running VRSF downpipes with Berk street axle back, and it also has a whistle. I have contacted Berk and sent videos of the sound, but they wont respond... I guess its time to search for a new exhaust

1er///M · 02-12-2017, 11:15 AM

I'm running a Berk muffler delete on an otherwise stock exhaust and I get the howl as well on my 12 N55.

I have a buddy with an N54 with Berk mids and street muffler with no whistle.

Haven't found a way to get rid of the noise. I'm thinking I might go back to the factory muffler with catless DPs until I can figure out another option.

04-04-2016, 12:25 PM	#1
rhodesman First Lieutenant 113 Rep 367 Posts Drives: E88 135i Join Date: Dec 2009 Location: Maryland iTrader: (2) Garage List 2010 BMW 135i [10.00]	Exhaust Howl / whistle I've researched this already but nothing was definitive or answered to my needs so I think this problem is a case-by-case issue and hoping I can solve it with your collective help. Last week I received my Berk Street Performance Axle back. This has been coupled to my Berk mid-pipes and my AR-DPs w/ racing C.A.T.s (this maybe an important part of this problem). After about a week of fiddling, adjusting, buying new gaskets, I'm at a loss. When the engine gets in the range of 5k-7k RPMs, I get this wonderful "howl" or "whistle" sound bellowing out from my exhaust. I cannot find the culprit. I've checked the inlets connection to the turbo's, I've adjusted the gaskets at both the DP-midpipe connection and the midpipe-axle back connection and still at 5k-7k, I'm a howling monkey (other, slightly "cooler", name: screaming eagle). I'm curious if anyone else has had this problem, what you have done to resolve this issue and also, I'm curious if MAYBE the racing C.A.T.s are in someway causing the howl due to the turbulent exhaust coming off the turbines hitting the fins/edges of the C.A.T.s. I'm seriously considering just buying a pair of BMS DPs just to try that theory, but I rather not throw money at a theory but instead a slightly better confirmed solution. Thoughts? Thanks! __________________ '10 N54 135i Cabrio \|\| ///M-Sport \|\| SCHWARZ/BEIGE *Mods:* JB4, Trebila Custom tune, FBO, Fuel-It Stg2 LPFP, Berk Street Performance w/ Berk Resonated Midpipes, & lots of little body/OEM+ mods
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04-04-2016, 02:19 PM	#2
Yeineken Colonel 1301 Rep 2,093 Posts Drives: '11 135i M Sport Join Date: Dec 2013 Location: Delmarva Peninsula iTrader: (3) Garage List '11 135i [8.20] '16 Ford Hatchback [0.00] '15 X5 [10.00]	I may be incorrect but I believe it's the y-pipe section near the tips. I believe the AFE exhaust also suffered from this problem; considering it had the same design near the tips. Attached Images __________________ Pyrat Clone
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04-04-2016, 02:54 PM	#3
rhodesman First Lieutenant 113 Rep 367 Posts Drives: E88 135i Join Date: Dec 2009 Location: Maryland iTrader: (2) Garage List 2010 BMW 135i [10.00]	I was afraid you would say that! I put in a message to Berk but have not heard back. Has anyone running a Berk Street Axle-Back come up with a way to stop this from happening? __________________ '10 N54 135i Cabrio \|\| ///M-Sport \|\| SCHWARZ/BEIGE *Mods:* JB4, Trebila Custom tune, FBO, Fuel-It Stg2 LPFP, Berk Street Performance w/ Berk Resonated Midpipes, & lots of little body/OEM+ mods
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04-04-2016, 03:29 PM	#4
TX135i Second Lieutenant 47 Rep 208 Posts Drives: 2012 135i Coupe DCT Join Date: Feb 2012 Location: Florida iTrader: (0)	Mine does not make the sound you describe, but the exhaust is all stock except for the axle back. It's a 2012 N55.
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04-04-2016, 03:40 PM	#6
ShocknAwe 1Addict 3233 Rep 7,894 Posts Drives: E82 Mutt, M57 Truck Join Date: Jul 2012 Location: Charleston iTrader: (22)	This is fairly common. Didn't have the issue myself when I had the Berk Street setup, but many others have, and not just with that exhaust. It's the y pipe split right before the tips. Could be that if we looked inside on noisy units, the welds could be less clean or complete. Just a thought. Also could be very slight variation in distance from the muffler to the y split. __________________ 2010 135i 6MT Jet Black N54/3 FE82 Mutt \| BUILD THREAD \| GARAGE SALE
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04-05-2016, 03:12 PM	#7
rhodesman First Lieutenant 113 Rep 367 Posts Drives: E88 135i Join Date: Dec 2009 Location: Maryland iTrader: (2) Garage List 2010 BMW 135i [10.00]	Well (as-of-now) if I keep the boost under 19psi there is no howl/whistle, I can live with that for the time being. I was wrong, whistle still there....damn. I made a call into Berk again and found out all their techs are out for some racing event... hopefully once they are done being a pit-crew, I'll get some answers/course of action. __________________ '10 N54 135i Cabrio \|\| ///M-Sport \|\| SCHWARZ/BEIGE *Mods:* JB4, Trebila Custom tune, FBO, Fuel-It Stg2 LPFP, Berk Street Performance w/ Berk Resonated Midpipes, & lots of little body/OEM+ mods Last edited by rhodesman; 04-05-2016 at 08:25 PM..
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04-06-2016, 05:56 AM	#8
Solo_M_Tech Brigadier General 1688 Rep 3,140 Posts Drives: 2014 M5 6MT Join Date: Nov 2013 Location: Massachusetts iTrader: (7) Garage List 2014 BMW M5 [0.00]	It's the tip design and how close the junction is to the end of the tips. It's the same effect as blowing air across the top of a beer bottle. My old exhaust did it, so I know what you are describing. Berk should take care of you. __________________ 2014 M5 6MT
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02-06-2017, 03:35 PM	#13
2008135i Private 11 Rep 58 Posts Drives: 2008 135i Join Date: Nov 2016 Location: Milwaukee, WI iTrader: (0)	I'm running VRSF downpipes with Berk street axle back, and it also has a whistle. I have contacted Berk and sent videos of the sound, but they wont respond... I guess its time to search for a new exhaust
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02-12-2017, 11:15 AM	#14
1er///M Enlisted Member 2 Rep 35 Posts Drives: 2012 135i Join Date: May 2015 Location: Toronto iTrader: (0)	I'm running a Berk muffler delete on an otherwise stock exhaust and I get the howl as well on my 12 N55. I have a buddy with an N54 with Berk mids and street muffler with no whistle. Haven't found a way to get rid of the noise. I'm thinking I might go back to the factory muffler with catless DPs until I can figure out another option.
	Appreciate 0 Quote