How to minimize Cabin noise

[david.avrahami@]

1987 carrera with a 100 cell cat & a Monty muffler )1 in 1 out)....great sporty sound.
I would like to minimize the sound inside the cabin somewhat...need your experience and advice on what is the best way of doing it....Thanks

[Ronnie's.930]

If you are asking about ways to insulate the cabin from noise, you will find that there are many old threads on the topic if you search keywords such as "sound deadening", "dynomat", "sound proofing" and the like (such as the following) -

Sound Deadening question.

Sound proofing

Products for Roll/Spray Sound Deadening?

[Jerome74911S]

This is tough, because these are simply noisy cars, regardless. There are various threads on PP about noise reduction. I read them all, then did more research elsewhere.

Without getting into a lengthy discourse (that's what it would take) on the process, suffice it to say that modest reduction in noise is all that is possible. I did everything in the highest-tech manner I could, using the latest cutting-edge materials available and my car is still loud.

OK, my car is quieter than it was, but if I'm going to drive more than a few miles I wear earplugs. People will talk about "Porsche music" and that you should learn to love it, etc., but my ears are giving out and the racket makes the car fatiguing to drive for very long.

You can reduce noise. Just be prepared to gut the interior down to the bone and build your new soundproofing from the metal up. Some searching of threads here, and elsewhere on the web, will get you plenty info on how to do the work.

All I'm saying is that you cannot expect much in this endeavor.

[BE911SC]

Put the stock muffler back on.

[4495]

I'd have to agree with the above ^^^^^

That or coat the interior with Dynamat.

[drodg]

Originally Posted by BE911SC

Put the stock muffler back on.

I agree

[Steve@Rennsport]

In my experience, Dynamat (and such products) do a far better job of damping road & tire noise than exhaust sounds.

I hate to say this, but I'd suggest re-installing the original factory muffler since ALL sport mufflers are louder than stock due to their internal baffles and sound deadening.

[alterednines]

[david.avrahami@]

Thanks guys for all the responses...I do love the sound, just wanted to diminish it somewhat...do you think that MLV suggested can be applied in the engine wall? , or do I need to use the sound deadening blanket offered by PP?

[Craig_D]

Question for everyone: Anybody familiar with the exact methods and materials that Singer is using on their 911? From the "Singer 911: All You Ever Wanted to Know - CHRIS HARRIS ON CARS" video, one of the guys shows and talks about the aeronautical sound control system employed on the Singer. I was very curious about the exact methods and materials. Anyone know more?

[david.avrahami@]

Thanks guys for all the responses...I do love the sound, just wanted to diminish it somewhat...do you think that MLV suggested can be applied in the engine wall? , or do I need to use the sound deadening blanket offered by PP?

[Autoban]

Originally Posted by david.avrahami@

Thanks guys for all the responses...I do love the sound, just wanted to diminish it somewhat...do you think that MLV suggested can be applied in the engine wall? , or do I need to use the sound deadening blanket offered by PP?

As a start replacing the sound deadening blanket (purchased from out host) will reduce the noise at least to some degree. The blanket was worn out on my '86 Cab when I bought it and after replacing it I can listen to the radio again (stock exhaust). If you want more noise reduction from the engine bay you need to add sound insulation material behind you back seats.

[RWebb]

to clarify, you are trying to reduce exhaust noise, right?

or chain noise; trans. noise; wind; tire; or???

[david.avrahami@]

Yes, It is the new muffler sound that I am trying to be more moderate...

[Jerome74911S]

Originally Posted by Craig_D

Question for everyone: Anybody familiar with the exact methods and materials that Singer is using on their 911? From the "Singer 911: All You Ever Wanted to Know - CHRIS HARRIS ON CARS" video, one of the guys shows and talks about the aeronautical sound control system employed on the Singer. I was very curious about the exact methods and materials. Anyone know more?

I don't know what Singer does, exactly (I watched the video), but sound deadening material used in aircraft is available and can be used in cars. I used some of it. Actually, the MLV and foam, and other materials I used in my car should be more effective, because of heavier MLV than you would want in an airplane, plus dampening coating, etc.

Never mind. I hope you can attenuate the exhaust note in your car, but I'm convinced that there is no magic out there, so keep that in mind.

[RWebb]

Singer may be using a computerized phase cancellation system

[Craig_D]

Originally Posted by RWebb

Singer may be using a computerized phase cancellation system

Well they didn't mention it at all. They said the guy who does sound reduction for airplanes used microphones and special materials that are put down in a specific way. You can see it and hear it (or not hear) in the video.

[Jerome74911S]

That's not impossible, but I'd be surprised in their application. From what I saw in the video mentioned above Singer is not on the bleeding edge with sound attenuation, so a computerized phase cancellation system appears unlikely to me.

Who knows. . . I wouldn't mind having such a system.

[Craig_D]

Aside from sound attenuation using internal cabin speakers and microphones, I'm more interested (and I think the OP might be also) in what materials and techniques the Singer guys used for a lightweight sound reduction system.

[r-mm]

I'm fairly new to these cars - also drive an 87 (presuming yours is a coupe) and have to say my first impression was how quiet they are. Under ~50mph my Carrera is pretty comparable to the Japanese sports box it replaced. Its the wind noise over 50 that is rather different. Have been told that the 964/993 windshields make a big difference in this regard. I believe but am not positive that there's an issue with the pinch weld flange being a different length on the pre 89's, but it also seems that a lot of people have done this modification. Between cutting down on noise, better aero and getting rid of annoying alum trim, seems like something highly worth pursuing, especially since a lot of our windshields are nicked up by this point.