Not the normal noise in here!!!

[unzie57]

I hope someone else out there has experienced this, I have run into dead ends so far. My 81' SC Coupe (no sunroof), has a lot of engine noise coming in from the vent slots above the rear window. If I am sitting in the car with the windows up and the motor off, any noise from around the rear of the sounds as clear as if I had no rear window. What and how much insulation should there be between the headliner and the roof? This is my second 911 and the first was not at all like this. Curious....

[plymouthcolt]

I have an '88 and it's the same for me. While sitting with the windows up, I ccan hear everything just like the windows were down.

[mambodave]

Originally posted by unzie57
I hope someone else out there has experienced this, I have run into dead ends so far. My 81' SC Coupe (no sunroof), has a lot of engine noise coming in from the vent slots above the rear window. If I am sitting in the car with the windows up and the motor off, any noise from around the rear of the sounds as clear as if I had no rear window. What and how much insulation should there be between the headliner and the roof? This is my second 911 and the first was not at all like this. Curious....

both of mine have been like this.... now even louder since Ive changed the exhaust... My Rover is quiet..so it dosnt bother me much, if I want quiet, i drive that...at least I dont have to answer the phone becuase I cant hear it

[DGL]

My 88 has the same noise issue and if it rains hard enough water bounces into those vents in shockingly large quantities. I haven't had the nerve to rip out the headliner yet, but in my research I've not seen a source that carries replacement parts for the headliner foam. Anyone know where I can get that?

[unzie57]

At least I am not the only one to wonder about this. And not the only one to wonder about a solution. I was considering weaving some open cell foam with adhesive on one side, from one side through to the other with a stiff length of wire and pressing against the metal to hold it in place. Since the slots are there to equalize pressure I don't think that would hurt anything...am I way off here?


Porsche list...
81' 911 SC Coupe
84' 944 Coupe
69' 911E Coupe
73' 914 2.0

[mthomas58]

Thanks for bringing this up again. I Posted a thread on this problem a week ago and got no replys.

Here's what I said:

Noisy rear window vents

Thanks!

[mthomas58]

Picture of vent with missing foam.

[Vereeken]

Yes the foam should be in those vents, or you will suffer extra noise. Since you do not have sunroof you also have no zipper in the headliner to get to the sunroof motor. If you would have disassembled that you will notice that there is a lot of foam to quit thing sdown. I assume that without if it acts like a loudspeaker.

Here is a suggestion to quite things down and add some safety....

[Paulporsche]

So it looks like the foam extends the width of the vent area, and I'm assuming it fills the entire gap up to the underside of the roof, but can anyone tell me how big it should be, front to back?

Thanks for that photo, Mark.

[Paulporsche]

A bump to see if anyone knows this.

[Vereeken]

Originally posted by Paulporsche
So it looks like the foam extends the width of the vent area, and I'm assuming it fills the entire gap up to the underside of the roof, but can anyone tell me how big it should be, front to back?

Thanks for that photo, Mark.

In my SC it is a three piece cardboard plate with the foam glued on to it, it is basically as wide as the total vent area and runs from the back some 25cm inward to the front of the car, mind you my SC has a sunroof , but I do not think that in a non sunroof car it will be bigger as you would hit part of the roof structure pretty soon, but you could get more insulation in place of the sunroof motor.

Michel

[Paulporsche]

Thanks, Michel. That's a big help.