I just installed new window rattle bumpers...




...and foam door insulators...




...on each side of the car. I just got back from a spin on the highway and road noise is down considerably. Its still no C5/6, but its a nice improvement. I plan on dynamatting (not necessarily that brand) the whole thing when I rip the carpet out. The best part I think is that the windows (besides not being wobbly when 1/2 down anymore) are now solidly sealed with the roof panel side weatherstripping like never since I've owned the car. I used to always get some good wind noise up there and water pours through when you spray at hose at that area. I'm willing to bet it doesn't now.

The insulators were a bit of a pain in the neck to install, but I got em' in there. They required a few custom slices and trims, especially around the door lock pin. Since they have probably about 1/8" thickness to them it is also much harder to get the door panels back into place. I had to use my knees to push the door grabs into place while screwing the two bolts into the handle area.

The crappy trashbag condom that GM used originally for noise prevention.



God these doors are a cluttered mess. Don't mind my ghetto speaker install from when I was like 19.


Bumper locations, one at the back and front of each door.





New vs. Old





Sorry, didn't take any shots of the new insulator installed. Keeping it in place just to get the panels on was hard enough!

 

That was the part I was waiting to see! Lets us now if there is a noticeable difference.

 

Been thinking hard about doing this soon.

 

The window bumpers are easy to do. Once you get the door panel off (which is kind of a project in itself) then you can have em' done in less than 5 minutes.

 

Definitely something that's on my long to-do list. Thanks for the info.

 

Great info,,,, as always

 

That project is on my list to. Nice info! Cool to see the old/new difference in shape and such. That clear plastic is suppose to be sound deadener? D'oh!

 

Actually it serves more as a water shield,moisture barrier.
Hence,they may no effort to make the doors shut solid and quiet.They always sounded like tin cans falling across the floor.

 

Where did you get those insulators?? From the regular aftermarket parts websites (eklers, madvet, etc.)?

 

Btw,I think a styrofoam board would work much better covering the silver tin like part of the door...in later cars GM uses thick styrofoam pieces to fill in the door hole areas behind the door panels.I have a 97 grand prix with a bad window regulator in the back door.I took the door panel off,water shield and was suprised to see this thick hard styrofoam piece in there.Those doors shut pretty quiet and I think those help.

Youd have to use a thinner styrofoam panel for the inside of the C4 door and can cut to fit and glue anywhere it may be needed.It would probably work much better than those inside panel insulators you can buy for 20 bucks or so....I tried those dark thin panels on my 86 and thought they sucked.You can even glue thin styrofoam panels to the back of the outer door shell on the inside for more added noise reduction.

Only problem is store bought styo-panels have alot of styrofoam beads so it can hold excess water.Youd have to coat it before putting it in places water would drip on,like behind the door shell in front of the window when its down...The styro in the grand prix is a hard brick like piece.Feels more like fiber than beads.

 

Interesting. I just had mine taken apart yesterday for the same reason. I had one of those stops at the center, and one at the back. None in the front. There was another provision for a third at the front but did not have one.

 

I'm not convinced that the dynamat does much if anything to cut down on road noise. It'll cut down on the very low frequencies, but that's it. Dense mass won't do anything to higher frequencies, you need lighter, thicker material for that. I put a layer on my floorboards, and two on the tranny tunnel, and thinking back, it was kinda a waste of time and effort.

Those door panel inserts do look effective though, since there's nothing to isolate noise from the noisy aluminum door panel or everything that goes through the fiberglass.

 

Same here. I added one though. The best thing I did on the doors was to install the metal armrest savers. Those really make the doors solid. Everyother vette I've been in, the door handle felt like it was going to tear off.