Road noise reduction: What worked for you?

[Kern Dog]

The auto manufacturers have done an excellent job of isolating the outside world from the inside in all the new cars that I have seen. I've been in some that are so quiet, you almost couldn't tell that there is a gasoline burning V8 up front.
This is absolutely NOT the case with the old cars that I have and I'm trying to change that.

The noise I've heard in my own cars can be traced to a number of areas. Some can be reduced, others are much harder to improve for a variety of reasons.

This last weekend, I went on an almost 900 mile road trip in my '70 Charger. The body is stock but does have a small front spoiler below the valance.

This was added years ago mainly for appearance but does hide some of the undercarraige from view.

While talking with others, it seems that the road noise I have is common to other classics. One of the faults lies here:

The rain gutters and vent window frames seem to catch the wind and make some noise.
The aerodynamics team that built the 69 Charger 500 and Daytona knew about this area.

That is part of it but there is more.

Exposed wiper arms, a windshield that seems recessed with a slight ridge of weatherstripping around the perimeter and the down slope of the roof around the quarter window top.

 

[Kern Dog]

The rake of the windshield is more upright than any new car. There is no changing that without negatively affecting the look of the car and inducing several other changes in the process.
Custom builds sometimes include shaving the rain gutters and other tricks:

There is some loss of the old car appearance here so it will not appeal to everyone.
The tight fitting custom bumper is a great look to me, though I'd prefer to see chrome.

 

[69 Sleeper Bee]

I became a framing carpenter and head cut man running the saws all day for 20 years.
I can barely hear any noises my car has now

 

[Kern Dog]

Solid lifter cam, headers, stiff suspensions, grippy tires....What are you willing to give up for less noise?
Me? I'm keeping all of that.
The outer door handles stand off the body.

That surely induces some turbulence compared to these:

I'm not changing those either.

 

[Kern Dog]

The late model cars do have some areas that cause drag and noise.
The scoops :

The inset grille:

Even the single scoop hood:

The wipers are hidden low though.

The spoiler is bolted to the trunk lid but does have gaps between it and the quarters.

Still, this car rolls down the road quietly.

 

[Tony Tee]

Rolls Royce has sound deadening material in side the wheels . They got it so quiet that they had to remove some of it. And I would guess that low profIle tires would make it louder! Saw it on, How it's Made.

 

[Kern Dog]

I have new carpet. There is sound absorbing mats from the firewall to the trunk divider.
This picture was taken before the 5 speed swap.

Given my many years in wood frame construction, my hearing is actually still okay. I hear things, I just sometimes have trouble knowing exactly where the noise is coming from. I don't get exhaust drone. My tires are like grooved slicks so I doubt much noise comes from there. No drive line vibrations. I have noticed that the road surface makes a huge difference though. New asphalt is the quietest. Grooved concrete seems to be the worst.

I am curious about what can be done. The A pillar deflectors may stop a fair amount of the noise but I suspect that even reproductions are big money if they are even available.
Door and glass alignment is a possibility. My hinges are original and since my door gaps are not as consistent as they could be, maybe there are some gains to be seen there.

 

[rmchrgr]

My Coronet suffers from ridiculous amounts of wind/road noise. I've been driving "old" cars for decades so I'm somewhat used to it but the Coronet is literally the worst I've ever experienced. It's even louder than my old '76 D100 was at 70 mph with the windows fully open and that thing was the opposite of aerodynamic.

From my vantage point, the vent windows are the major contributors. A solid window eliminates several leak points. Even with a minimal street machine interior my Duster is way quieter - no vent windows. In the Coronet anything above 40 mph I get a constant, high-pitched, focused sound like an air gun right at my ear. The vent window seals don't fit well, there's at least a 1/4" gap between the top of the seal and the actual frame. This seems to be common. I have a friend who just completed a high-end resto on a '68 Super Bee and his repro vent window seals have the same dumb gap They don't close very tightly either.

The cowl area creates a lot of noise too so make sure the floor vent seals and wiper pivot seals are good and the vent doors shut tight. You can put foam strips around the vent openings to help with any unwanted incoming air. Windshield seals dry out and shrink which creates plenty of areas for incoming air to make itself known.

When I was at the dealership, we'd get a lot of "NVH" complaints. (Noise, Vibration, Harshness) First thing we'd do with excessive road noise complaints is try to find leaks in the door and window seals. You shut all the windows and put the fan on full blast then step out, close all the doors and spray around the cabin openings with soapy water to see where the pressure was escaping from. It worked every time, even just a little folded over piece can set the whole seal out of whack.

 

[64fury74charger]

I really like the 1st and 2nd gen Chargers. 3rd gen Chargers are somewhat more aerodynamic and a little less prone to wind noise having concealed wipers and other style changes. They still have a fair amount of road noise and insulation helps but I think there’s only so much and the bodies have larger gaps between panels and the unibody construction certainly adds to the noise transfer as well.

 

[Kern Dog]

I agree. The open cowl/hidden wipers probably helps along with ventless door glass.

 

[Bighouse]

I believe the new challenger has quite a few cavities and even the “A” pillars filled with foam. A lot of newer cars are packed with foams. Not something you’d want to do to your classic, but it sure makes collision repair interesting.

 

[rmchrgr]

 

[Nate S]

Gotta say my ‘64 Sport Fury is one of the quieter ones I’ve had. The A pillar and rain gutter are covered with chrome pretty thoroughly. In fact , there’s no rain gutter any more with the chrome on there. Hadn’t thought of that until your discussion here.

 

[moparedtn]

Noise?
Fred is loud as hell with the 3" duals and single-chamber Flow-wannabe's on him....
especially at 65mph/3000rpm. All windows down as always...
My hypersensitivity had to do more with vibrations - and of course, heat - being transmitted
into the cabin.
There's a noticeable (to me) slight harmonic vibration at around 59-60mph; it's less lower or
higher speeds than that. I attribute it to the drivetrain being all cobbled with unknown engine
balance and a bellhousing/clutch/transmission all alien to the car - and to each other.
When I'm under there, I'm always wiggling the driveshaft to check for u-joints and such, but
who knows if the thing is "indexed" properly to the rear housing (which is also not what came
with the car)?
It all calms down at about 64mph, so I don't think it's some horrendous engine balance issue
anyways....

Lookit, these cars are obviously old technology, not to mention unitized construction.
There literally is nowhere for noises/vibrations to be isolated to - or from.
50 years of nvh development have left them in the dust (although it hasn't been totally
eliminated - ever driven a modern "Brampton" car? These are so damn rigid and unitized that
you feel and hear every damn thing the low-profile tires encounter, even if better muffled).

 

[slimt]

I dont mind the noise. Windows down and cruising to where ever. Cant hear nothing but wind. Cant even hear the wife.

 

[dadsbee]

WHAT...

 

[1967coronet]

I wear hearing aids in both ears. This current pair i have I can control with a small button on top of aid.
Also I can adjust them with a app on my phone.
I have cured all the noises in my 67.

 

[Kern Dog]

At idle and low speeds, I hear the radio just fine. At 60 and up, I have to crank it up to drown out the wind. That kills the ability to have a decent conversation.
I know for some dudes, that is fine since they don't want to hear what the wife is saying.

 

[Photon440]

I'd be interested in wind noise comparisons to similar years but different aerodynamics: compare a 1970 road runner to a 1970 Superbird for example. They'd have to have identical running gear and tires etc. to make a meaningful comparison.

 

[ckessel]

Greg, if you get a chance, go by a body shop and check out a job being done on large panel replacements or repair. Along with what you did on the floor, there are deadening pads inside the doors on the back of the skins, in various places on quarter panels, roof skins on the backside, back of hood and many others. Sometimes its just sprayed in material. The panels are like skins on a drum. They will transmit outside noise through them unless something id on the back side. You can do some aero work on the outer trim but since they were not designed for aero it will be tough.