Reading some threads on sound deadening a 928 I found mention of a GTS door gasket that has a lip on it that the older ones don't have the "lip"...

I also noticed on my car, a 1988 S4, the passenger side has a thin gasket mounted to the interior side of the door sill and there is no gasket on the driver side.
Is the GTS gasket they speak of attached to the door or is it the thin rubber thing that is missing on one side of my car?

I'm trying to make it as quiet as possible and have put the expanding foam in the cavity behind the rear speakers and in some places behind the forward cover of the rear wheel wells. I also cut a layer of 1/2 inch closed cell foam ( taped together pieces of a sleeping bag pad for camping) and have it covering the rear hatch floor under the carpet, my spare tire cavity is packed full of a loosely folded tarp to cut noise and do double duty as a tarp if needed...

Now it's time to attack the doors because they are the only noisy source left and before I order that missing gasket I want to know does the GTS have superior door gaskets that improve noise deadening? I want to order the right parts including the one missing part or all new if my one is not a part of the better version....
I plan to remove both door panels and tighten things up, clean or replace felt and put some kind of material on the inside of the door as well as replace the plastic with something too.

 

The new style rubber door seals with the lip were introduced in the 1991 production run. The early cars - including mine with VIN 0102, and the one after mine did not come with those seals, yet.

BTW: The same is true to the rubber pieces between A-Pillar trim and windshield

Anyway, I am not sure what the other gasket is you are refering to - is this the black velvet covered plastic one between headliner / A-Pillar cover and body?

That one is probably not for noise reduction, but to make for a smoother visual transition between the interior materials and body.

 

Basically it is a thin rubber piece that the bottom of the door seal would mate up against when the door closes. It bridges the gap between the door sill and the body. It's hard to even notice, at least on a black car anyway. I've had my car for two years and just now noticed it was missing on the driver side....

 

Craig,
If you buy a new door seal it is to the latest standard.
They up issued the older to the latest.
Roger

 

Ah, now I know which one... That's the one that seals the gap between rocker covers and the body - right?

I don't think it's there to reduce noise, just to keep dirt from getting in there and causing damage.

 

Both door seals on my '85 are the updated type from the GTS. Whether or not it makes a difference in noise is difficult to say because 99.9% of the time, when you go from the old style to the new, it's because the old style is worn out. I replaced mine because I couldn't get the doors adjusted properly without having them leak. But how a new old-style seal would compare to a new current seal is anyone's guess. It's like stainless brake lines. Everyone says the difference is tremendous, but that's also because they're replacing rubber hoses that are decades old, with brand new parts. Again, the real test is comparing stainless brake lines to brand new rubber lines.

The other question you should ask yourself is whether it's possible to get $350 worth of sound deadening out of new seals.

IMO, they do make the door close tighter. I had to adjust the latch on mine after I put the new seal on so it would actually open and close properly. Even now it requires a firmer pull or push then it did before. It also keeps water out.

You can also try to add some sound deadening material like dynamat (although dynamat is ridiculously expensive and there are cheaper, better alternatives out there) under the door panels. That helps some as well.

 

Thanks!
If the seals are that expensive I'll go ahead and address the inside of the doors first since my seals seem to be in good shape.
Nicole, yes, that is the piece that is missing, the one between rocker covers and the body. I'll go ahead and order that one after I pull apart the door panels to see what else I might need to order.

 

New seals are nice because they prevent some of the rain drops falling from the roof on the seat when you open the door... but they'll cost you.

 

Craig,
I did the sound deadening treatment several months ago. Lotsa foam, Raamat, and Ensolite. Made a significant difference. Air intrusion is the biggest culprit. Along with the sound of the air you get outside noise as well. Mine still has air leaks at the door...........next on the list.
David

 

Also consider the GTS window seals that go on each side of the windshield. Cheap and easy to install. Don't have a picture of these, but a good upgrade.

 

+1000

 

Nicole - do you sell them, and wold they fit onto the 86? Do they just slide right in the groove?

 

Hi Ed: You can order them from your favorite 928 parts supplier.