E92 M3 hood question

Merlin_83 · 11-04-2017, 08:26 AM

Greetings,

Kind of a silly question, is the lack of sound insulation on the underneath of the hood done so that the sound of engine can be heard better ?

I know the hood is made of aluminum to reduce weight

, as are the front fenders made of fiber reinforced plastic, but people ask me frequently why I have no sound barrier. I always state it's done on purpose by the factory to enhance the intake sounds

So is this all correct ?

Thank you,
Merlin

deansbimmer · 11-04-2017, 08:47 AM

I suspect it is due to the low clearance between the intake plenum and hood. I can't imagine insulation could exist there without rubbing.

carenthuziast · 11-04-2017, 08:58 AM

Insulation would also be bad since it traps heat

inTgr8r · 11-04-2017, 09:41 AM

^^
^
and weight

Merlin_83 · 11-04-2017, 12:29 PM

...Ah, ok those all make sense

///M Power-Belgium · 11-04-2017, 12:50 PM

Quote:

Originally Posted by Merlin_83

...Ah, ok those all make sense

Without insulation we hear better the rod knock

'ringmeister · 11-04-2017, 05:46 PM

Quote:

Originally Posted by ///M Power-Belgium

Without insulation we hear better the rod knock

this made me LOL, well played sir!

///M Power-Belgium · 11-04-2017, 05:48 PM

Quote:

Originally Posted by 'ringmeister

this made me LOL, well played sir!

All my pleasure Sir

BOOF-M3 · 11-06-2017, 12:54 PM

Quote:

Originally Posted by 'ringmeister

Quote:

Originally Posted by ///M Power-Belgium

Without insulation we hear better the rod knock

this made me LOL, well played sir!

Send me a PM as I am unable to PM you for some reason. Need your first name for the Dragon run.

BOOF-M3 · 11-11-2017, 10:01 AM

Quote:

Originally Posted by 'ringmeister

Quote:

Originally Posted by ///M Power-Belgium

Without insulation we hear better the rod knock

this made me LOL, well played sir!

Still can't get a hold of you through PM. Can you PM me or post on the tail of the Dragon thread. Thanks.

Nov 19th Tail of the Dragon http://www.m3post.com/forums/showthread.php?t=1427143

Edward · 11-11-2017, 01:33 PM

That a nice thought and all but in reality it's probably so they didn't have to spend the money to outfit some 80k plus units with extra parts.

DSilk · 11-13-2017, 08:15 AM

The bulge in the bonnet of the M3 (both 39X and e46) was placed there to provide needed clearance for the engine and intake. Placing insulation there would have required a taller bulge, and insulation would have trapped more heat in a car that already runs on the warm side to begin with. If cost saving was a primary issue BMW would have foregone the full shield under the engine. Besides, the only purpose insulation under the bonnet serves is to reduce engine noise intrusion. M3 buyers are enthusiasts, by and large, and we like hearing induction sounds and other mechanical noises.

doogee · 11-13-2017, 08:16 AM

BMW stopped using hood insulation on the 2009+ 3 Series.

Cost cutting.

carenthuziast · 11-13-2017, 08:49 AM

Quote:

Originally Posted by DSilk

The bulge in the bonnet of the M3 (both 39X and e46) was placed there to provide needed clearance for the engine and intake. Placing insulation there would have required a taller bulge, and insulation would have trapped more heat in a car that already runs on the warm side to begin with. If cost saving was a primary issue BMW would have foregone the full shield under the engine. Besides, the only purpose insulation under the bonnet serves is to reduce engine noise intrusion. M3 buyers are enthusiasts, by and large, and we like hearing induction sounds and other mechanical noises.

With freezing temperatures in the colder parts of the US, the M3's definitely cool down a lot faster without the heat trapping sound insulation.

'ringmeister · 11-17-2017, 05:29 PM

Quote:

Originally Posted by BOOF-M3

Send me a PM as I am unable to PM you for some reason. Need your first name for the Dragon run.

hi Boof, appreciate that you reached out but I will not be able to make it to the dragon. Best of luck, hope you guys have great weather and empty roads!

jon

BOOF-M3 · 11-17-2017, 05:31 PM

Quote:

Originally Posted by 'ringmeister

Quote:

Originally Posted by BOOF-M3

Send me a PM as I am unable to PM you for some reason. Need your first name for the Dragon run.

hi Boof, appreciate that you reached out but I will not be able to make it to the dragon. Best of luck, hope you guys have great weather and empty roads!

jon

Have been trying for days lol. Ok, you are an honorary driver.

roastbeef · 11-17-2017, 05:35 PM

If it had it, I'd have taken it out.

Solo_M_Tech · 11-17-2017, 09:10 PM

Quote:

Originally Posted by DSilk

The bulge in the bonnet of the M3 (both 39X and e46) was placed there to provide needed clearance for the engine and intake. Placing insulation there would have required a taller bulge, and insulation would have trapped more heat in a car that already runs on the warm side to begin with. If cost saving was a primary issue BMW would have foregone the full shield under the engine. Besides, the only purpose insulation under the bonnet serves is to reduce engine noise intrusion. M3 buyers are enthusiasts, by and large, and we like hearing induction sounds and other mechanical noises.

1. The bulge on the E46 M3 is cosmetic. Serves no other purpose.
2. the insulation isn't only for sound suppression, but also fire suppression.
3. The full shield under the engine bay is for aerodynamic purposes. without it, pressure will build in the engine bay, increasing the chances of the hood popping open at speed, creating an accident. It also improves fuel mileage and emissions.

Outside of that, I agree with your other 2 points.

11-04-2017, 08:26 AM	#1
Merlin_83 Merlin 474 Rep 730 Posts Drives: 2012 BMW M3 6MT w/ZCP Join Date: Feb 2014 Location: United States iTrader: (0) Garage List 2012 BMW M3 ZCP [0.00] 2008 BMW 335i [0.00] 2008 BMW 335xi [0.00]	E92 M3 hood question Greetings, Kind of a silly question, is the lack of sound insulation on the underneath of the hood done so that the sound of engine can be heard better ? I know the hood is made of aluminum to reduce weight , as are the front fenders made of fiber reinforced plastic, but people ask me frequently why I have no sound barrier. I always state it's done on purpose by the factory to enhance the intake sounds So is this all correct ? Thank you, Merlin __________________ 2012 E92 M3 ZCP \| 2008 E90 335xi \| 2008 E90 335i \|
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11-04-2017, 08:47 AM	#2
deansbimmer BimmerPost Supporting Vendor 3749 Rep 2,907 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	I suspect it is due to the low clearance between the intake plenum and hood. I can't imagine insulation could exist there without rubbing.
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11-04-2017, 08:58 AM	#3
carenthuziast Captain 373 Rep 801 Posts Drives: 2013 E93 M3 6MT Join Date: Jun 2017 Location: Northern Virginia iTrader: (0)	Insulation would also be bad since it traps heat
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11-04-2017, 09:41 AM	#4
inTgr8r Lieutenant General 2426 Rep 11,667 Posts Drives: M2 Comp Join Date: Mar 2006 Location: Toronto iTrader: (10)	^^ ^ and weight __________________ '21 M2C Hockenheim Silver '18 718 Cayman S Lava Orange (sold) '13 E92 M3 Santorini Blue (sold) '07 Z4 M Coupe Alpine White (sold)
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11-04-2017, 12:29 PM	#5
Merlin_83 Merlin 474 Rep 730 Posts Drives: 2012 BMW M3 6MT w/ZCP Join Date: Feb 2014 Location: United States iTrader: (0) Garage List 2012 BMW M3 ZCP [0.00] 2008 BMW 335i [0.00] 2008 BMW 335xi [0.00]	...Ah, ok those all make sense __________________ 2012 E92 M3 ZCP \| 2008 E90 335xi \| 2008 E90 335i \|
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11-11-2017, 01:33 PM	#11
Edward Colonel 377 Rep 2,982 Posts Drives: 2013.9999 E92 Jerez ZCP Join Date: May 2010 Location: Los Angeles iTrader: (2)	That a nice thought and all but in reality it's probably so they didn't have to spend the money to outfit some 80k plus units with extra parts.
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11-13-2017, 08:15 AM	#12
DSilk Major 550 Rep 1,148 Posts Drives: 2008 BMW M3 Coupe Join Date: Jun 2015 Location: South Florida iTrader: (0) Garage List 2015 Jaguar XJ [0.00] 2015 Jaguar XF [0.00] 2014 VW GTI [0.00] 2008 BMW M3 Coupe [0.00] 2007 VW Passat 2.0T [0.00]	The bulge in the bonnet of the M3 (both 39X and e46) was placed there to provide needed clearance for the engine and intake. Placing insulation there would have required a taller bulge, and insulation would have trapped more heat in a car that already runs on the warm side to begin with. If cost saving was a primary issue BMW would have foregone the full shield under the engine. Besides, the only purpose insulation under the bonnet serves is to reduce engine noise intrusion. M3 buyers are enthusiasts, by and large, and we like hearing induction sounds and other mechanical noises.
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11-13-2017, 08:16 AM	#13
doogee Major 748 Rep 1,256 Posts Drives: '08 M3, '09 328xi Sport Wagon Join Date: Oct 2008 Location: Ancaster, ON, Canada iTrader: (0)	BMW stopped using hood insulation on the 2009+ 3 Series. Cost cutting. __________________
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11-17-2017, 05:35 PM	#17
roastbeef Lieutenant General 11585 Rep 12,725 Posts Drives: E92 M3 Join Date: Nov 2010 Location: Orange County, CA iTrader: (4)	If it had it, I'd have taken it out. __________________ Instagram; @roastbeefmike
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