Sound Deadening Model 3

[Fernand]

Wow, I just took some spectra tapping on different surfaces, which BTW is a very good way to spot resonances that would amplify road noise. My wheel wells don't, fenders don't. So far a very strong suspect is the frunk liner's tall vertical wall that faces the cabin. It's a perfect drum. The spectrum also matches up well with that of the loudest rumble I got inside the cabin at highway speeds, so it would likely contribute.

Lining that with any kind of adhesive rubbery schtuff until it's deadened would likely help. Removing the frunk "tub" is pretty easy, but if we just stick some material onto that wall without pulling out the whole assembly we won't really lose frunk capacity and we can evaluate the effects, and maybe do a more permanent job if it helps. I'd guess the trunk tub also has some drum surfaces, that's next to go tap on.

 

[Mrcarcrazy]

Wow, I just took some spectra tapping on different surfaces, which BTW is a very good way to spot resonances that would amplify road noise. My wheel wells don't, fenders don't. So far a very strong suspect is the frunk liner's tall vertical wall that faces the cabin. It's a perfect drum. The spectrum also matches up well with that of the loudest rumble I got inside the cabin at highway speeds, so it would likely contribute.

Lining that with any kind of adhesive rubbery schtuff until it's deadened would likely help. Removing the frunk "tub" is pretty easy, but if we just stick some material onto that wall without pulling out the whole assembly we won't really lose frunk capacity and we can evaluate the effects, and maybe do a more permanent job if it helps. I'd guess the trunk tub also has some drum surfaces, that's next to go tap on.

View attachment 479719

Super easy to remove that tub so I’ll go ahead and put some noico on that as well. Hoping I can start this project on Sunday. Waiting on my thinsulate still. Damn you amazon.

 

[cab]

Wow, I just took some spectra tapping on different surfaces, which BTW is a very good way to spot resonances that would amplify road noise. My wheel wells don't, fenders don't. So far a very strong suspect is the frunk liner's tall vertical wall that faces the cabin. It's a perfect drum. The spectrum also matches up well with that of the loudest rumble I got inside the cabin at highway speeds, so it would likely contribute.

Lining that with any kind of adhesive rubbery schtuff until it's deadened would likely help. Removing the frunk "tub" is pretty easy, but if we just stick some material onto that wall without pulling out the whole assembly we won't really lose frunk capacity and we can evaluate the effects, and maybe do a more permanent job if it helps. I'd guess the trunk tub also has some drum surfaces, that's next to go tap on.

View attachment 479719

I put some on my Model S frunk...didn’t notice a difference I’m afraid.

 

[Fernand]

I put some on my Model S frunk...didn’t notice a difference I’m afraid.

@cab There you go, nothing like testing ideas and not making assumptions. That's why I'd rather try different spots on the intact liner wall before putting even an hour into pulling the tub (and putting it back).

I'm curious now: was your Model S frunk wall very "drummy"? ''Cause the Model 3 one sure is, very much so. And did you find that your treatment changed that, before you tested the noise in the cabin while driving?
.

 

[Magnets!]

So if there is noise resonating in the frunk, perhaps a Frunk lid carpet liner would help cut it down? The same people that sell the wheel liners and trunk liner make a frunk lid liner.

 

[Fernand]

It's intuitively obvious that if you pad everything inside a vehicle with both deadening and sound absorbing materials, it will be quieter. It's just that it gets expensive, requires a lot of work, and is heavy. The ideal solution is to find those spots where specific tricks yield the most benefit. If you have a large metal or plastic surface, for instance, it has resonant frequencies, just like a drum, or on a much larger scale, bridges that vibrate apart when the wind and loads happen to strongly excite those frequencies. But on a drum all it takes is a finger at the right spot to turn that tom-tom into a potato.

Given the cost and labor and weight of the total or generalized gooping approach, it's beyond my stamina and wallet, and most of it will be wasted, contributing next to nothing. Placing small amounts of sticky rubbery stuff that absorbs vibration (and turns it into tiny amounts of heat) in the right spots, like the finger on the drum, is more like it. I wish somebody made maps of various cars showing the critical spots and cavities. In the meantime, we are all stuck with a lot of the "I guess it helped a bit" results.

 

[skatefriday]

It's intuitively obvious that if you pad everything inside a vehicle with both deadening and sound absorbing materials, it will be quieter. It's just that it gets expensive, requires a lot of work, and is heavy. The ideal solution is to find those spots where specific tricks yield the most benefit. If you have a large metal or plastic surface, for instance, it has resonant frequencies, just like a drum, or on a much larger scale, bridges that vibrate apart when the wind and loads happen to strongly excite those frequencies. But on a drum all it takes is a finger at the right spot to turn that tom-tom into a potato.

Given the cost and labor and weight of the total or generalized gooping approach, it's beyond my stamina and wallet, and most of it will be wasted, contributing next to nothing. Placing small amounts of sticky rubbery stuff that absorbs vibration (and turns it into tiny amounts of heat) in the right spots, like the finger on the drum, is more like it. I wish somebody made maps of various cars showing the critical spots and cavities. In the meantime, we are all stuck with a lot of the "I guess it helped a bit" results.

This is precisely why when people ask me how I like my M3 I say, "It's a fantastic computer on wheels, but Tesla is still figuring out how to actually build them."

I hope they succeed, but my wife's Honda Accord Hybrid Touring is a better car to ride in. It has adaptive cruise control that doesn't balk at overpasses, and it's dead quiet. Is it as fast as my M3? Not at all. But quick off the line only lasts for 5 seconds. For the other 30 minutes that I'm getting to my destination I wish I were in my wife's car.

 

[Zcd1]

It's intuitively obvious that if you pad everything inside a vehicle with both deadening and sound absorbing materials, it will be quieter. It's just that it gets expensive, requires a lot of work, and is heavy. The ideal solution is to find those spots where specific tricks yield the most benefit..I wish somebody made maps of various cars showing the critical spots and cavities. In the meantime, we are all stuck with a lot of the "I guess it helped a bit" results.

Exactly.

An obvious, easy spot to muffle would be the opening from the parcel shelf to the trunk. It's there for pressure relief when closing the trunk lid so it wouldn't be a good idea to block it off with anything airtight, but it seems intuitive that adding a baffle in that area would help. I'd also think that adding a layer of material to the rest of the underside of that shelf could help.

I may also get roof shades, as all that glass is surely reflecting the sounds emanating from other parts of the cabin, making the overall noise level worse.

I'm somewhat torn on whether to line the trunk and frunk lids. It couldn't hurt and would be easy to do, but it may not help much.

 

[Fernand]

I say, "It's a fantastic computer on wheels, but Tesla is still figuring out how to actually build them." For the other 30 minutes that I'm getting to my destination I wish I were in my wife's car.

Nothing's stopping you, and she might well trade you once we show her how to use it, and she too will be riding the freeway maze in autopilot like riding the train.
.

 

[KenC]

So if there is noise resonating in the frunk, perhaps a Frunk lid carpet liner would help cut it down? The same people that sell the wheel liners and trunk liner make a frunk lid liner.

I've bought all those things, and I thought the frunk liner had the least effect on sound, but I think it looks good!

 

[Mrcarcrazy]

I've bought all those things, and I thought the frunk liner had the least effect on sound, but I think it looks good!
View attachment 480575

It does look good!

 

[Magnets!]

Yes looks good. I was looking at the ebay listing and was wondering does it screw into existing holes? or how does it fasten?

In terms of noise reduction which of the items do you think worked best?

 

[Fernand]

From going around and tapping - and you don't need a spectrum analyzer for that - the whole center of the frunk lid is pretty resonant on my Model 3. The liner looks great, @KenC , but I don't know if it's bonded to the metal enough to deaden it. With the frunk closed, if you tap/slap on it, is it dead and potato-like now?

My plastic trunk tub bottom rings pretty loud, not the sides, just the bottom. Then if I put the cover on (and that's quite inert on its own), the combination makes a strong kick-drum. That trunk tub could use some treatment! When I stopped driving with the rear sets folded down, it was a big improvement. Noise comes from the back. I'd expect padding the bottom of the trunk tub and that side spot on the panel above the wheel to be worth a little effort.

It seems like there's padding behind the Model 3's bigger steel body surfaces in most cases. Maybe each car has its own untreated drumming areas. One bad spot on mine is on the right (passenger) side, on the rear wheel-well panel. That's hollow and pretty resonant, X marks the spot. Sorry about the sketch quality ;-)

And around center of the driver's door (not on the passenger side), below where the mirror sits, it's hollow and the steel is un-padded, it rings pretty loud. There are other less significant ones, but these are the worst spots on my car.

 

[Perscitus]

Don't think so. The included fasteners are longer, but you'd have to squish it all together to get it to fasten, and squishing the thinsulate kind of defeats the purpose, no? Here's pic of the included fasteners, sorry I didn't put the old ones in for comparison.
View attachment 478527

Even better get these 8mm fastners. They work in all, including the trickiest, locations once the new liner is sandwiched with the OE and/or thinsulate etc.

 

[BioSehnsucht]

Why not just put the thinsulate on the back side of the original liner?

 

[Fernand]

I don't know if that's true of all Model 3s, but the factory wheel wells on mine are well lined, they are acoustically inert. Check yours out, tap on them.

There are lots of areas that are far far more in need of treatment. IMHO unless your wheel wells are messed up and resonate like an empty garbage can, the very real vibration being passed from road+tire up that rigid linkage to the chassis can't possibly be affected by thickening the factory wheel well liners.
.

 

[Magnets!]

I don't know if that's true of all Model 3s, but the factory wheel wells on mine are well lined, they are acoustically inert. Check yours out, tap on them.

There are lots of areas that are far far more in need of treatment. IMHO unless your wheel wells are messed up and resonate like an empty garbage can, the very real vibration being passed from road+tire up that rigid linkage to the chassis can't possibly be affected by thickening the factory wheel well liners.
.

Is the model 3 suspension different from any car? Don't they all have a rigid linkage to the chassis?

 

[Fernand]

Is the model 3 suspension different from any car? Don't they all have a rigid linkage to the chassis?

Of course. That's the point. The tires vibrate on the road and excite the chassis which resonates in different spots at specific frequencies, (and/or loose things rattle). You hear it because you're as if inside a drum, what you hear is the surfaces pushing and pulling air and creating sound waves, amplifying the vibration of the tires.

The spectra show most of that is low frequency rumbling. Low frequency sound has a long wave length, so it easily passes through barriers that higher frequencies get blocked by. That's why after you've closed the door to that practice-room the bass makes it through anyway. If that bass makes it through 2 thicknesses of sheetrock, it's not going to be stopped by adding a little layer of padding. So it's most important to suppress it at the source: those surfaces that the wheel vibration is driving to push/pull the air and create what we hear as a rumbly road noise sound. Surfaces that are solidly held in place don't rattle. Surfaces that are padded in the right spots don't resonate. My wheel wells don't rattle or resonate, so they aren't adding to the noise. Adding more padding to them wouldn't change that. And padding wouldn't block any low frequency sound waves that originated elsewhere either.

 

[KenC]

Yes looks good. I was looking at the ebay listing and was wondering does it screw into existing holes? or how does it fasten?

In terms of noise reduction which of the items do you think worked best?

The trunk liner I think had the most effect, but that's if you have the hole. And I thought the front wheel liners helped, but it's totally subjective and probably alot of placebo. On the other hand, the placebo effect does work, so there's that.

As for installing, it has the same bolts with long nuts as the rear trunk shelf liner, to fit in the 2 holes in the frunk. Then they give you a roll of red adhesive tape. I did the following:

 

[R1Fast]

I've bought all those things, and I thought the frunk liner had the least effect on sound, but I think it looks good!
View attachment 480575

Can you share the link to the frunk liner? Maybe it's posted already but if so I am blind,