997 2005-2012 911 C2, C2S, C4, C4S, GTS, Targa and Cabriolet Model Discussion.

REDUCING EXCESSIVE hGHWY ROAD NOISE ON 911/911s

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  #16  
Old 10-06-2009, 07:32 AM
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Originally Posted by dndodd
I had some Dynamat "extreme" laying around (and I have never wanted to tear apart the insides to add some of this) so I knocked on the car in a few places like the inner fenders. There is no sound deadening there so I decided to add some. I put some Dynamat on each inner fender closes to the passenger compartment ,on the front lower plastic panel under the steering box, and on the plastic under the transmission. Note; I didn't try to cover every square inch at all.
Can you post any pictures of what you`ve done? Did you put dynamat outside facing street or on inside surfaces?
 
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Old 10-06-2009, 07:34 AM
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My P-Zero's are wicked loud. I hate 'em and plan to switch to Bridgestones once they wear out. My wifes Boxster had Bridgestones.... they are sooooo quiet....

Matt
 
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Old 10-06-2009, 07:37 AM
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Sorry I din't take any pictures. All the dynamt was put on The inside surfaces of the plastic.

The idea being to absorb or trap the sound before it can be transferred to the passenger compartment. I did not put any on the steel body of the car behind these areas.
 
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Old 10-06-2009, 07:39 AM
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Originally Posted by Matt(in MA)
My P-Zero's are wicked loud. I hate 'em and plan to switch to Bridgestones once they wear out. My wifes Boxster had Bridgestones.... they are sooooo quiet....

Matt

Are the Bridgestones quiet when they are worn out?
 
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Old 10-06-2009, 09:31 AM
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dndodd - your post reminds me of a similar thing I did to my Alfa GTV when I rebuilt the body 15 years ago. It suffered considerable road noise so when it was on stripped and on the rotisserie I took the time to apply additional underbody protection in and around the rear axle housing. There was none there - I think Luigi had a bad day when it was built in '72!

If the 997 is like that then what you're suggesting makes sense. Some others may not want to add weight but done properly and using the right product there is very little additional weight. I used a water based Glasurit Underbody sealant. In total it would have added maybe a couple of pounds tops.
 

Last edited by aggie57; 10-06-2009 at 09:37 AM.
  #21  
Old 10-06-2009, 11:43 AM
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Originally Posted by dndodd

I had some Dynamat "extreme" laying around (and I have never wanted to tear apart the insides to add some of this) so I knocked on the car in a few places like the inner fenders. There is no sound deadening there so I decided to add some. I put some Dynamat on each inner fender closes to the passenger compartment ,on the front lower plastic panel under the steering box, and on the plastic under the transmission.



I've used Dynamat on other cars and it works well. I'm sure it made a difference in your case.
 
  #22  
Old 10-06-2009, 11:55 AM
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Some say that N2-filled tires are quieter tires. If there's any truth to that it must be be because N2-filled tires have no moisture. Thus, if tires are filled with dry air they should be just as quiet (or as loud). What do you think?
 
  #23  
Old 10-06-2009, 12:03 PM
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Originally Posted by adias
Some say that N2-filled tires are quieter tires. If there's any truth to that it must be be because N2-filled tires have no moisture. Thus, if tires are filled with dry air they should be just as quiet (or as loud). What do you think?

This is bait, right? I had a PT Barnum flash for a sec...
 
  #24  
Old 10-06-2009, 12:07 PM
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Originally Posted by casaforte9
The 911 with 19" wheels seems to have a lot of tire roar on Highways

When speccing a 911 base does getting 18" wheels help on the highway from a road noise perspective?

Thanks
Yes, (although who knows by how much) not because the 18s are smaller in diameter, but because the 18 inch specs are narrower in the rear 265mm vs. 295mm. For this reason, the car will move around less in a straight line as well. The most common tire fitted is the Michelin Pilot Sport in both sizes and it is not a quiet tire relative to other max performance tires.

Keep in mind, if highway comfort is a priority, the PDK has another gear - 7th which lowers rpms and engine noise as well as improving gas economy.

Good luck
 

Last edited by drspeed; 10-06-2009 at 12:10 PM.
  #25  
Old 10-06-2009, 12:24 PM
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Since I don't commute in my car I have learned to live with the noise (concrete and expansion joints are the worst). I had PZeros that were pretty worn at one point and had switched to PS2's and there was a minimal reduction in noise. I love every other aspect of the car that the noise is just one of the "quirks" of the car.
 
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