Exhaust Issue

Chandon · 10-30-2014, 05:22 AM

I have a 135i Axle-back with the resonator deleted, had this since August last year. It used to crackle and pop like crazy while also being quite high pitched in higher rpm's.

Recently in the past few months I have noticed that all these crackles and pops have disappeared, also the exhaust note has become a lot deeper and more mellow, it doesn't sound like it used to and it is quite obvious.

It had sounded high pitched and popped and burbled A LOT for the past year, but all of a sudden is no longer like that. Would anyone have any insight as to why the exhaust would suddenly change so drastically?

631twentyeighteye · 10-30-2014, 08:01 AM

beat on it a little bit. Mine mellows out when i'm babying it and then starts to really crackle and pop after revving it out for a bit.

MightyMouseTech · 10-30-2014, 08:21 AM

Take it for a good 1hr or 2 high speed cruise and blow the carbon out of it.

Chandon · 10-30-2014, 08:22 AM

Quote:

Originally Posted by 631twentyeighteye

beat on it a little bit. Mine mellows out when i'm babying it and then starts to really crackle and pop after revving it out for a bit.

Mm weird thing is I took it to the track 2 weeks ago, I'm sure the exhaust would've got plenty hot, still nothing.
And I'm guessing that applies for above too since the drive there was 2.5 hours each way at around 120km/h.

MightyMouseTech · 10-30-2014, 09:19 AM

Quote:

Originally Posted by viciousgook

Quote:

Originally Posted by 631twentyeighteye

beat on it a little bit. Mine mellows out when i'm babying it and then starts to really crackle and pop after revving it out for a bit.

Mm weird thing is I took it to the track 2 weeks ago, I'm sure the exhaust would've got plenty hot, still nothing.
And I'm guessing that applies for above too since the drive there was 2.5 hours each way at around 120km/h.

You need to run it lean to clean it out. WOT will increase the carbon buildup.

Chandon · 10-31-2014, 02:45 AM

Quote:

Originally Posted by MightyMouseTech

You need to run it lean to clean it out. WOT will increase the carbon buildup.

Interesting, isn't running lean bad for the engine?

Dackelone · 10-31-2014, 05:23 AM

Sounds like you had your SW updated by a BMW dealer. The latest SW has that anti-tuner SW and the exhaust note is more deeper and pops a lot less. Only real way to get the pops back is to get a PPK flash or an aftermarket SW flash.

Chandon · 10-31-2014, 05:27 AM

Quote:

Originally Posted by Dackelone

Sounds like you had your SW updated by a BMW dealer. The latest SW has that anti-tuner SW and the exhaust note is more deeper and pops a lot less. Only real way to get the pops back is to get a PPK flash or an aftermarket SW flash.

Not sure if this applies for N52? I haven't been back to the dealership since getting my car nonetheless.

Dackelone · 10-31-2014, 05:32 AM

Quote:

Originally Posted by viciousgook

Not sure if this applies for N52? I haven't been back to the dealership since getting my car nonetheless.

Oops! Yea, your right. I thought you had a 135i. I just re-read your original post. What I said doesn't apply to N52's. Sorry.

MightyMouseTech · 11-01-2014, 10:21 AM

Quote:

Originally Posted by viciousgook

Quote:

Originally Posted by MightyMouseTech

You need to run it lean to clean it out. WOT will increase the carbon buildup.

Interesting, isn't running lean bad for the engine?

Steady cruise is the leanest time for an engine. Normal.

andrey_gta · 11-01-2014, 02:24 PM

Did you change your intake in any way?

My car has an 135i axle back too. With USA airbox it was loud/angry, with Euro box it was quiet ( except cold start) and I was sad but the car felt slightly faster. Now with the RM intake elbow added its loud again.

Also check your 135i muffler Flap if it works. If it is closed/malfunctioning its possible the noise is gone.

Pig Farmer · 11-01-2014, 02:43 PM

A couple years ago, I helped my friend cut open a brand new M3 exhaust. The exhaust had zero miles on it. We were surprised to find that the fiberglass(?) stuffing was in a plastic bag. If BMW does the same with the 135i exhaust, I suspect the plastic bag breaks down over time and changes the exhaust note.

Chandon · 11-02-2014, 06:42 AM

Quote:

Originally Posted by andrey_gta

Did you change your intake in any way?

My car has an 135i axle back too. With USA airbox it was loud/angry, with Euro box it was quiet ( except cold start) and I was sad but the car felt slightly faster. Now with the RM intake elbow added its loud again.

Also check your 135i muffler Flap if it works. If it is closed/malfunctioning its possible the noise is gone.

Yep.. Injen intake, although I fitted it over a year ago and the exhaust still sounded awesome with plenty of crackles and burbles.
Will check the flap tomorrow, had it "golf tee'd" since I got it so will see if it's broken.

andrey_gta · 11-02-2014, 02:14 PM

Quote:

Originally Posted by viciousgook

Yep.. Injen intake, although I fitted it over a year ago and the exhaust still sounded awesome with plenty of crackles and burbles.
Will check the flap tomorrow, had it "golf tee'd" since I got it so will see if it's broken.

This link may help
http://www.1addicts.com/forums/showthread.php?t=963343

Our fibers are not in a Bag as stated before.

I would check the welds or joins for leaks. its possible they have developed over time

Chandon · 11-02-2014, 08:10 PM

Quote:

Originally Posted by andrey_gta

This link may help
http://www.1addicts.com/forums/showthread.php?t=963343

Our fibers are not in a Bag as stated before.

I would check the welds or joins for leaks. its possible they have developed over time

So my valve is still open, nothing broken. Checked the welds too, no leaks.
Could it possibly have something to do with the thicker intake piping?

Kizzu · 11-03-2014, 09:53 AM

Have you been noticing this change since the tune or before it? Maybe the tune changed something in the intake/exhaust flaps.

Chandon · 11-03-2014, 08:42 PM

Quote:

Originally Posted by Kizzu

Have you been noticing this change since the tune or before it? Maybe the tune changed something in the intake/exhaust flaps.

It started happening a few months prior to the tune, so definitely not.

TheSt|G · 11-04-2014, 07:58 AM

Quote:

Originally Posted by Kizzu

Have you been noticing this change since the tune or before it? Maybe the tune changed something in the intake/exhaust flaps.

Exhaust flaps are vacuum based, not electronically controlled.

VGR00 · 11-07-2014, 03:28 PM

I have the BMW PE and I notice a change in amount of crackles, pops and overall sound depending on weather. Can't give an explanation or back it up scientificlly. I think the car also "self tunes" in between services so it could be a combination of weather (intake temp / humidity) and running lean or richer (self tune / adaptation)

Suprgnat · 11-07-2014, 03:43 PM

Quote:

Originally Posted by TheSt|G

Exhaust flaps are vacuum based, not electronically controlled.

Sorta, kinda, except for the P/N 11747810831 solenoid that controls the vacuum flap. (Not that a tune would normally effect it)

MarkkyyMan · 11-08-2014, 02:33 PM

Quote:

Originally Posted by MightyMouseTech

You need to run it lean to clean it out. WOT will increase the carbon buildup.

Please explain this one.

MightyMouseTech · 11-08-2014, 06:31 PM

Quote:

Originally Posted by MarkkyyMan

Quote:

Originally Posted by MightyMouseTech

You need to run it lean to clean it out. WOT will increase the carbon buildup.

Please explain this one.

WOT is the richest possible condition except for cold start. To clean out the carbon, you need the hottest possible condition with the least amount of carbon. That condition is steady state highish speed cruise.

Best way to clean out an engine/exhaust is to go for a several hour highway cruise with the cruise on.

10-30-2014, 05:22 AM	#1
Chandon Major 99 Rep 1,102 Posts Drives: 1M Join Date: Apr 2013 Location: Sydney, Australia iTrader: (1)	Exhaust Issue I have a 135i Axle-back with the resonator deleted, had this since August last year. It used to crackle and pop like crazy while also being quite high pitched in higher rpm's. Recently in the past few months I have noticed that all these crackles and pops have disappeared, also the exhaust note has become a lot deeper and more mellow, it doesn't sound like it used to and it is quite obvious. It had sounded high pitched and popped and burbled A LOT for the past year, but all of a sudden is no longer like that. Would anyone have any insight as to why the exhaust would suddenly change so drastically?
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10-30-2014, 08:01 AM	#2
631twentyeighteye Colonel 198 Rep 2,239 Posts Drives: 08 335i Join Date: Aug 2012 Location: Long island iTrader: (7)	beat on it a little bit. Mine mellows out when i'm babying it and then starts to really crackle and pop after revving it out for a bit. __________________ 08 e93 335i MT
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10-30-2014, 08:21 AM	#3
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	Take it for a good 1hr or 2 high speed cruise and blow the carbon out of it.
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10-31-2014, 05:23 AM	#7
Dackelone European Editor 10589 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	Sounds like you had your SW updated by a BMW dealer. The latest SW has that anti-tuner SW and the exhaust note is more deeper and pops a lot less. Only real way to get the pops back is to get a PPK flash or an aftermarket SW flash. __________________ Dackel's European Delivery Museum Guide
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11-01-2014, 02:24 PM	#11
andrey_gta Brigadier General 298 Rep 4,040 Posts Drives: 130i coupé ;) Join Date: Nov 2011 Location: Bimmerpost iTrader: (1) Garage List 2008 BMW 128i [10.00]	Did you change your intake in any way? My car has an 135i axle back too. With USA airbox it was loud/angry, with Euro box it was quiet ( except cold start) and I was sad but the car felt slightly faster. Now with the RM intake elbow added its loud again. Also check your 135i muffler Flap if it works. If it is closed/malfunctioning its possible the noise is gone. __________________ 128i Sport 6MT converted to Euro 130i spec, 3.73 diff, tuned by evolve ~220 whp 207 wtq(ft-lb) SAE In-progress: //M front arm, M3 rack, e36M lip Wishlist: Coils, n55 mnts, headers, LSD, e60 finn diff "The 1-series is the last car that BMW engineered before the Germans, as a car-making culture, fell out of love with driving." - R&T 2013 135is
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11-01-2014, 02:43 PM	#12
Pig Farmer Major 340 Rep 1,293 Posts Drives: E92M Join Date: May 2010 Location: Florida iTrader: (0)	A couple years ago, I helped my friend cut open a brand new M3 exhaust. The exhaust had zero miles on it. We were surprised to find that the fiberglass(?) stuffing was in a plastic bag. If BMW does the same with the 135i exhaust, I suspect the plastic bag breaks down over time and changes the exhaust note.
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11-03-2014, 09:53 AM	#16
Kizzu First Lieutenant 41 Rep 306 Posts Drives: Bmw 125i Black Sapphire Join Date: Oct 2013 Location: Malta iTrader: (0)	Have you been noticing this change since the tune or before it? Maybe the tune changed something in the intake/exhaust flaps.
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11-07-2014, 03:28 PM	#19
VGR00 Major 53 Rep 1,497 Posts Drives: 430i Gran Coupe Join Date: Feb 2007 Location: Brisbane - Australia iTrader: (1)	I have the BMW PE and I notice a change in amount of crackles, pops and overall sound depending on weather. Can't give an explanation or back it up scientificlly. I think the car also "self tunes" in between services so it could be a combination of weather (intake temp / humidity) and running lean or richer (self tune / adaptation)
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