99% Sure This Isn't Wastegate Rattle

icabod7 · 01-27-2012, 12:19 AM

Hi All,

So there is a higher-vibration rattling sound I get when I accelerate and keep the engine at a higher RPMs, but its a little different for each gear. So for example, in second gear I hear it around 3-4000 RPMs, but in third gear its slightly higher, and slightly higher again in fourth gear. It sounds like its coming from somewhere in the cabin. But upon closer listening I think its coming from directly below my shifter -- from the transmission. I can make the sound go away by shifting to a higher gear. For reference I have a 2008 6MT with about 29K miles and a BMW short shifter kit. I have Cobb Stage 1 Aggressive -- but I'm pretty sure I heard the sound even before flashing.

From all that I've read searching the forum, I do not believe this is the wastegate rattle. I don't hear the noise on start up or idle -- nor do I hear it upon deceleration from higher RPMs, which is characteristic of wastegate problems.

Any ideas as to what it could be?

Tommeh · 01-27-2012, 05:40 PM

Hmmm not sure. I swear my car makes so many little noises and rattles. Or im just really really paranoid.

infinitekidM2C · 01-27-2012, 06:35 PM

injectors; it's normal

Dackelone · 01-27-2012, 06:42 PM

Since you think its coming from the shifter I would start poking around there. Try jacking up the car(and use some jack stands!) and look at the exhaust bracket (#5 & #6 in the foto bellow)... that holds the mid-pipes. I bet that bracket could be loose or missing. IF not I would then look at the rest of the echaust and also check out your shift linkage - perhaps something is loose down there. My bet is on your exhaust brace/bracket(s).

icabod7 · 01-27-2012, 07:01 PM

Quote:

Originally Posted by Dackelone

Since you think its coming from the shifter I would start poking around there. Try jacking up the car(and use some jack stands!) and look at the exhaust bracket (#5 & #6 in the foto bellow)... that holds the mid-pipes. I bet that bracket could be loose or missing. IF not I would then look at the rest of the echaust and also check out your shift linkage - perhaps something is loose down there. My bet is on your exhaust brace/bracket(s).

Thanks, Dack -- I will poke around down there and see what I can find. I cross-listed this on e90post.com and a few other folks mentioned that perhaps it could be the downpipes (something loose).

Dackelone · 01-27-2012, 07:06 PM

Quote:

Originally Posted by icabod7

Thanks, Dack -- I will poke around down there and see what I can find. I cross-listed this on e90post.com and a few other folks mentioned that perhaps it could be the downpipes (something loose).

You know with the engine cold(so you don't burn your hands) use a rag and grab the tail pipes. Move the exhaust around and see if you hear anything. This might be a good way to see if somethings loose on the exhaust w/o having to jack up the car and get all dirty.

IF not its time to get out the rubber hammer and start poking around there.

01-27-2012, 12:19 AM	#1
icabod7 Second Lieutenant 18 Rep 254 Posts Drives: 2008 135i Coupe Join Date: Jun 2011 Location: Dallas iTrader: (0)	99% Sure This Isn't Wastegate Rattle Hi All, So there is a higher-vibration rattling sound I get when I accelerate and keep the engine at a higher RPMs, but its a little different for each gear. So for example, in second gear I hear it around 3-4000 RPMs, but in third gear its slightly higher, and slightly higher again in fourth gear. It sounds like its coming from somewhere in the cabin. But upon closer listening I think its coming from directly below my shifter -- from the transmission. I can make the sound go away by shifting to a higher gear. For reference I have a 2008 6MT with about 29K miles and a BMW short shifter kit. I have Cobb Stage 1 Aggressive -- but I'm pretty sure I heard the sound even before flashing. From all that I've read searching the forum, I do not believe this is the wastegate rattle. I don't hear the noise on start up or idle -- nor do I hear it upon deceleration from higher RPMs, which is characteristic of wastegate problems. Any ideas as to what it could be? __________________ cdv delete \| clutch stop \| bmw performance ssk \| meisterschaft gt \| berk mids \| dinan cai \| helix fmic \| m3 subframe bushings, swaybar, front and back suspension bits \| dinan stage 1 suspension \| dinan cf strut brace \|gc camber plates \| dinan oil cooler \| apex ec-7s w/PSSs \| cobb stage 1 + fmic
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01-27-2012, 05:40 PM	#2
Tommeh Lieutenant 56 Rep 481 Posts Drives: 96 BMW M3 & 16 GMC Canyon Join Date: Mar 2011 Location: Washington iTrader: (0)	Hmmm not sure. I swear my car makes so many little noises and rattles. Or im just really really paranoid.
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01-27-2012, 06:35 PM	#3
infinitekidM2C Major General 4207 Rep 5,728 Posts Drives: 2019 M2 Competition Join Date: Nov 2007 Location: Orange County, CA iTrader: (4) Garage List 2019 M2 COMPETITION [9.50] 2008 135i (my old car) [7.39]	injectors; it's normal
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01-27-2012, 06:42 PM	#4
Dackelone European Editor 10589 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	Since you think its coming from the shifter I would start poking around there. Try jacking up the car(and use some jack stands!) and look at the exhaust bracket (#5 & #6 in the foto bellow)... that holds the mid-pipes. I bet that bracket could be loose or missing. IF not I would then look at the rest of the echaust and also check out your shift linkage - perhaps something is loose down there. My bet is on your exhaust brace/bracket(s). Attached Images
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