What causes the gurgle sound?

deletedelete · 09-29-2009, 08:13 PM

I have a muffler delete so its just straight pipes. I dont think the coupe has a resonator either.

And without mufflers I heard a gurgle sound when decelerating. I like the sound, I just wanted to know what causes it.

JoosyJoos · 09-29-2009, 08:21 PM

Its just the back pressure in the exhaust system. As you let off the gas it creates a bit of a vacuum and reverberates within the exhaust piping I believe. Try going downhill and feathering the throttle in first or 2nd gear.. you should get a lot of burbling. It makes my day every day in my parking garage

Jonny550 · 09-29-2009, 08:22 PM

thats backfiring and it sounds more pronounced on coupes the sedan ( because of the resanator) IMHO i think it sounds pretty badass.

Alpine335TT · 09-29-2009, 08:24 PM

Interesting how the car does this in stock condition also.

deletedelete · 09-29-2009, 08:25 PM

Yeah I love when slowly pulling up to a stop and hearing the gurgle. Its noticeable enough that people standing on the sidewalk will look over at me.

Ill trying going downhill to see if I can make it happen, thanks!

JoosyJoos · 09-29-2009, 08:28 PM

I've also had my friends say that when I shift off from approximately 5500-6000rpm that I can sometimes get a little pop and flame. If you're fully catless you might be able to pull it off too. I'm not so sure its happened more than a handful of times for me though.

lul77 · 09-29-2009, 08:37 PM

if you had an aftermarket muffler would removing the secondary car on a coupe (e92) make the gurgle deeper or more pronounced? mine doesn't sound as sexy as i'd like

JoosyJoos · 09-29-2009, 08:40 PM

If you got rid of the secondary cats it should make it more pronounced because it should free up more back pressure hence the gains from removing cats in the first place.

Woot 500!

lul77 · 09-29-2009, 08:41 PM

Quote:

Originally Posted by JoosyJoos

If you got rid of the secondary cats it should make it more pronounced because it should free up more back pressure hence the gains from removing cats in the first place.

Woot 500!

thanks and congrats on 500 posts

deletedelete · 09-29-2009, 08:42 PM

Will you still pass emissions with only 1 set of cats?

lul77 · 09-29-2009, 08:44 PM

Quote:

Originally Posted by Prowess Symphony

Will you still pass emissions with only 1 set of cats?

think that'd depend on your state law

haha but i get my inspection sticker for $75 so i don't need to worry about passing anything

deletedelete · 09-29-2009, 08:46 PM

Quote:

Originally Posted by lul77

think that'd depend on your state law

haha but i get my inspection sticker for $75 so i don't need to worry about passing anything

Im in md. I dont have many special "friends" to get me inspection stickers.

So the coming from the engine its one pipe with two cats, then an x-pipe, then it forks out to the dual exhaust?

JayKay335i · 09-29-2009, 08:47 PM

A nice blond or red head would cause a gurgling sound... Especially since you drive a BMW.

Eyeman · 09-29-2009, 08:47 PM

What I luv most is the way the step in DS mode downshifts and gives the gurgle!

Madson · 09-29-2009, 08:48 PM

Quote:

Originally Posted by Prowess Symphony

Will you still pass emissions with only 1 set of cats?

+1?????Anyone in ny?

lul77 · 09-29-2009, 08:51 PM

Quote:

Originally Posted by JayKay335i

A nice blond or red head would cause a gurgling sound... Especially since you drive a BMW.

hahaha damn man i miss those comments dude. by the time u come back to the east coast the teeny boppers you were eying on wednesdays might finally be legal bro

Dan335i · 09-29-2009, 08:54 PM

You should pass emissions with no problems if you have the primary cats still on.

Alpine335TT · 09-29-2009, 10:59 PM

Quote:

Originally Posted by Prowess Symphony

Will you still pass emissions with only 1 set of cats?

Yes.. as long as you don't have a CEL

I have no primary or secondary cats

deletedelete · 09-29-2009, 11:03 PM

Engine#-----Cat1*----Cat2*----Xpipe=====Tips~

Is that what it looks like under there? So one cat would be removed and a straight pipe added?

Alpine335TT · 09-29-2009, 11:05 PM

The primary cats are on the downpipes... the 2ndary cats are on the midpipes which connect to the downpipes....

deletedelete · 09-29-2009, 11:07 PM

Quote:

Originally Posted by Alpine335TT

The primary cats are on the downpipes... the 2ndary cats are on the midpipes which connect to the downpipes....

Darn it. Im gonna have to find a pic to see what it looks like under there.

Can I see everything from looking underneath the car if its jacked up?

Alpine335TT · 09-30-2009, 12:08 AM

The secondary cats yes, but the downpipes are nestled in there.. you should be able to see the primary cats though.

09-29-2009, 08:13 PM	#1
deletedelete Major General 361 Rep 5,873 Posts Drives: m Join Date: Nov 2008 Location: usa iTrader: (14) Garage List 2013 e92 M3 [0.00] 2011 e93 M3 (sold) [0.00] 2009 335xi (sold) [0.00]	What causes the gurgle sound? I have a muffler delete so its just straight pipes. I dont think the coupe has a resonator either. And without mufflers I heard a gurgle sound when decelerating. I like the sound, I just wanted to know what causes it. __________________ ---> Click For xi/xDrive Suspension Compatibility List <---
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09-29-2009, 08:21 PM	#2
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	Its just the back pressure in the exhaust system. As you let off the gas it creates a bit of a vacuum and reverberates within the exhaust piping I believe. Try going downhill and feathering the throttle in first or 2nd gear.. you should get a lot of burbling. It makes my day every day in my parking garage __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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09-29-2009, 08:22 PM	#3
Jonny550 Brigadier General 241 Rep 4,936 Posts Drives: 2012 550i Xdrive Join Date: Feb 2009 Location: Jersey Shore iTrader: (14)	thats backfiring and it sounds more pronounced on coupes the sedan ( because of the resanator) IMHO i think it sounds pretty badass. __________________ [SIGPIC][/SIGPIC] .
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09-29-2009, 08:24 PM	#4
Alpine335TT Major 146 Rep 1,403 Posts Drives: LCI E92 M-Sport 335i Join Date: Sep 2007 Location: DC Metro iTrader: (5)	Interesting how the car does this in stock condition also. __________________ Current: E46 M3 (CB) Retired: E92 335i (AW) // E92 LCI M-Sport 335i (LMB) MISCHIEF.TV
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09-29-2009, 08:25 PM	#5
deletedelete Major General 361 Rep 5,873 Posts Drives: m Join Date: Nov 2008 Location: usa iTrader: (14) Garage List 2013 e92 M3 [0.00] 2011 e93 M3 (sold) [0.00] 2009 335xi (sold) [0.00]	Yeah I love when slowly pulling up to a stop and hearing the gurgle. Its noticeable enough that people standing on the sidewalk will look over at me. Ill trying going downhill to see if I can make it happen, thanks! __________________ ---> Click For xi/xDrive Suspension Compatibility List <---
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09-29-2009, 08:28 PM	#6
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	I've also had my friends say that when I shift off from approximately 5500-6000rpm that I can sometimes get a little pop and flame. If you're fully catless you might be able to pull it off too. I'm not so sure its happened more than a handful of times for me though. __________________ 1997 M3 Coupe - BMWCCA I-Prepared #22 2006 M Roadster - 23,000 miles and slowly counting
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09-29-2009, 08:37 PM	#7
lul77 Lieutenant Colonel 111 Rep 1,758 Posts Drives: e92 Join Date: Jan 2008 Location: nj iTrader: (12)	if you had an aftermarket muffler would removing the secondary car on a coupe (e92) make the gurgle deeper or more pronounced? mine doesn't sound as sexy as i'd like __________________ available for photoshoots in NJ/NY area. click links for ::samples:. http://lul77.zenfolio.com/
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09-29-2009, 08:40 PM	#8
JoosyJoos Major 113 Rep 1,347 Posts Drives: 2011 335d Join Date: Apr 2007 Location: Atlanta, GA iTrader: (1) Garage List 2008 BMW 335i [0.00]	If you got rid of the secondary cats it should make it more pronounced because it should free up more back pressure hence the gains from removing cats in the first place. Woot 500!
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09-29-2009, 08:42 PM	#10
deletedelete Major General 361 Rep 5,873 Posts Drives: m Join Date: Nov 2008 Location: usa iTrader: (14) Garage List 2013 e92 M3 [0.00] 2011 e93 M3 (sold) [0.00] 2009 335xi (sold) [0.00]	Will you still pass emissions with only 1 set of cats? __________________ ---> Click For xi/xDrive Suspension Compatibility List <---
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09-29-2009, 08:47 PM	#13
JayKay335i Banned 189 Rep 5,046 Posts Drives: ///M323 DCT Join Date: Apr 2009 Location: North Dakota; its best DUHHHHHH iTrader: (1)	A nice blond or red head would cause a gurgling sound... Especially since you drive a BMW.
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09-29-2009, 08:47 PM	#14
Eyeman Colonel 121 Rep 2,037 Posts Drives: 2008 135 blk, blk, step Join Date: Jan 2009 Location: Atlanta, GA iTrader: (0) Garage List 1994 Porsche 968 Cab [0.00] 2017 AMG GTS [0.00] 1994 Porsche 968 Coupe [0.00] 1977 Mercedes 450SE ... [0.00] 2008 135 [8.00]	What I luv most is the way the step in DS mode downshifts and gives the gurgle! __________________ Injen, RR OCC, MadDad Whisper, donut spare, 19x8.5et43fr 19x9.5et45r Volk LE37's, rear fenders rolled/pulled, PSS4S 225/35fr 255/30r, KW V1's, AR coated catless dps, Cross strutbar, CF grills and license plate holder, iCarbon diffuser, ETS black anodized FMIC, M3 control arms, Quaife, ER chargepipe, ForgeDV's, Topspeed Custom Tune, V3sims, Braille, Andrey_GTA rear hub mod, Ebay Mstyle front bumper and performance style side skirts.
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09-29-2009, 08:54 PM	#17
Dan335i Lieutenant Colonel 32 Rep 1,786 Posts Drives: 07 335i coupe 6MT,w/sp. pack. Join Date: Oct 2007 Location: orange county NY iTrader: (2)	You should pass emissions with no problems if you have the primary cats still on.
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09-29-2009, 11:03 PM	#19
deletedelete Major General 361 Rep 5,873 Posts Drives: m Join Date: Nov 2008 Location: usa iTrader: (14) Garage List 2013 e92 M3 [0.00] 2011 e93 M3 (sold) [0.00] 2009 335xi (sold) [0.00]	Engine#-----Cat1----Cat2----Xpipe=====Tips~ Is that what it looks like under there? So one cat would be removed and a straight pipe added? __________________ ---> Click For xi/xDrive Suspension Compatibility List <---
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09-29-2009, 11:05 PM	#20
Alpine335TT Major 146 Rep 1,403 Posts Drives: LCI E92 M-Sport 335i Join Date: Sep 2007 Location: DC Metro iTrader: (5)	The primary cats are on the downpipes... the 2ndary cats are on the midpipes which connect to the downpipes.... __________________ Current: E46 M3 (CB) Retired: E92 335i (AW) // E92 LCI M-Sport 335i (LMB) MISCHIEF.TV
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09-30-2009, 12:08 AM	#22
Alpine335TT Major 146 Rep 1,403 Posts Drives: LCI E92 M-Sport 335i Join Date: Sep 2007 Location: DC Metro iTrader: (5)	The secondary cats yes, but the downpipes are nestled in there.. you should be able to see the primary cats though. __________________ Current: E46 M3 (CB) Retired: E92 335i (AW) // E92 LCI M-Sport 335i (LMB) MISCHIEF.TV
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