• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Road noise reduction: What worked for you?

I live about 20 miles away from Greg and I also drove down to Spring Fling, in the Dart. About 1000 miles round trip, mostly with the the vent windows open and the windows down. The wife rode shotgun and we didn't even bother playing the radio because it was too loud inside the car. However, last fall I installed subframe connectors while redoing the interior and they made a noticeable difference. We drove the Dart to Spring Fling in 2018 and this time gone were the rattles, squeaks, and groans. SFC make a big difference lessening ambient noises.
 
I did put sound deadener mats on the back sides of the outer door skins and the quarters behind the window regulators.
A hydraulic cam would cut down on some noise. The MP 528 solid calls for a pretty wide lash... .028 intake, .032 exhaust. I closed it up to .024 and .028 but it still is loud compared to a hydraulic.
I drove with the windows up and the A/C going.
 
Before my resto I thought it was a bit much road noise.

I added a Dynamat type sound deadener to the whole floor, upp half the firewall and back to below the tray.
Added thick isolation to the tray cover and to the big board behind the rear seat.
Sprayed the insides of the doors with a rubber paint, then new seals to the windows.

This really helped with the road noise and i can still hear the engine clearly which I like.....with those fm 40s.
 
Ear plugs

65591EB3-6763-45C2-8C47-085573F0A5FB.jpeg
 
I live about 20 miles away from Greg and I also drove down to Spring Fling, in the Dart. About 1000 miles round trip, mostly with the the vent windows open and the windows down. The wife rode shotgun and we didn't even bother playing the radio because it was too loud inside the car.
Dennis H says that his buddy John has a '70 Cuda with a rowdy 440 and it rolls down the road really quiet due to extensive sound deadening. The E body cars had no vent windows though.
Vent windows have their advantages but I agree that that whole arrangement adds several points that not only can leak but also cause drag and turbulence.
On the way home from work today, I thought about how my other Charger seems to have less road noise. The 383 does have a smaller cam and is hydraulic so it runs a lot quieter. "Jigsaw" has no carpet or insulation on the firewall, no package tray and about half a headliner. Going down the road, I hear noises from everywhere but the window seals. That may not be a legitimate observation, on second thought. Maybe if all the other noises were to be eliminated, I might then notice wind noise if it were there.
Out in the shop, I decided to look at the gaps between the vent frame and the body.
Ginger:

Vent 1.JPG


Now Jigsaw:

Vent 2.JPG


It was clear that the frame on Ginger was tilted outward compared to the frame on Jigsaw.

Note the gap between the top edge of the pencil and the inner stainless molding:

Vent 4.JPG


Now look at Jigsaw. Much tighter gap.

Vent 3.JPG


On the bottom of the door shell, there is a hole with a body plug in it.

Vent 9.JPG


Up inside is a 1/2" hex nut.

Vent 10.JPG


I backed it off and pried the nut and threaded rod to the outside of the door shell. This in effect tilted the top of the vent frame toward the body. I wasn't able to get it to sit as close as it is on Jigsaw. I got it about 3/4 of the way there and tightened the nut.
A test drive at 50, 60 and 65 mph showed there to be less road noise but some still remains. I was able to hear the stereo a bit clearer than before. The weatherstrips are original and although they look decent, they may have shrunk or deformed enough in a few places to let some noise in. They don't leak water. That is good.
 
Vent windows are worth the extra noise. They were created so one could flick their cigarette butt out at 60 mph without the risk it would fly back in and burn the rear seat.
 
I’ve seen 68-70 Chargers in movies where the vent windows are eliminated. It looks okay to me. The 2 door Dart models went to a one piece side glass in 1973. Looking at profile shots of a 72 and 73, the later car looks less busy.
I wouldn’t change mine but it wouldn’t bother me if these cars didn’t have them. When I want airflow, I just roll down the window. I had a 71 then an 84 Chevy truck and rarely ever used those vent windows either.
 
Auto Transport Service
Back
Top