Sound Deadening Project

[johnloov]

for sure I will find another type r and do a ride along

I would see if you can ride along in someone else’s FL5 on a road you are familiar with and see if there is a difference. I can’t imagine there would be that much difference between our cars unless they the factory made an error or switched a process/material mid-cycle. My car is an early ‘24 purchased in January.

Sponsored

 

[johnloov]

Here is some more data I collected on the way to Laguna Seca.
1) Driving at 75mph on a good road surface.

2) Driving at 75mph on an excellent road surface like glass.

Attached few more data points all at 75

 

[johnloov]

I’m not very sure how accurate the iPhone decibel meter is in how much of the real story it is portraying. When my wife got in the car, she said it was much quieter and now she can only hear noise from under our feet.

Also Harry’s garage when he does Car reviews he takes decibel meter readings and you can hear the car inside is very loud but his meter shows 75 dB. Remarks how the interior is very noisy.



Conclusion is the car is much quieter and the decimeter seems not to show a true representation of noise on the iPhone application.

I may do the floors next…. Why not…. The car is feeling more solid to drive.

 

[Imped]

I did a quick test using the same app yesterday.

At a steady state 70 mph (cruise) on a flat, smooth, relatively quiet highway surface I recorded a max of 70.9 dB and average of 68.6 dB.

Since I haven't seen it mentioned yet, this is with the fake exhaust noise disabled.

 

[johnloov]

I did a quick test using the same app yesterday.

At a steady state 70 mph (cruise) on a flat, smooth, relatively quiet highway surface I recorded a max of 70.9 dB and average of 68.6 dB.

Since I haven't seen it mentioned yet, this is with the fake exhaust noise disabled.

Thanks for that data point.

Here is what I do know.

1) Stock FL5 Type R - My ears would still ring, after a long drive, even with ear plugs in, when the car was stock. Somehow that frequency and those sound waves were still penetrating my inner ear through the ear plugs. I was getting major migraines.

2) Doors, Trunk, Wheel Wells Dampened - Now my ears don't ring, after a long drive, with ear plugs in and the dampening installed. They do ring a bit, without earplugs. The car is much more civilized, and somehow the Type R dampening works better, and I can't figure it out, but it's for the better. The car feels like a vault.

3) The Floors - TBD - The rest of the road noise seems to be coming from the floor, which is also a tin can.

Had a fantastic day on Laguna Seca. The car was extremely stable. I ran in the Type R mode, nannies on, but for sure the car was not bouncing around at all like it used to in Type R mode.

Ran a 1 min 59, which was my fastest time, without cooking the brakes ( could have shaved at least 5 seconds easy with harder braking ) and the helmet does dampen noises quite a bit. Stock Type R brakes, suspension. One of the instructors told me, if I add like 100 lbs to the car, I'm only going to loose 1/10th of a second. So... I'm thinking of also dampening the floors next.

Spoke to other FL5 owners and they are aware of the road noise, and they had their cars on 18's. One of them mentioned he starting get lots of rattles due to the resonance, as they do use/abuse their cars.

Yes, I have very sensitive hearing. The Alfa 4c blew out my ears, with too much road noise, and now certain frequencies, even with ear plugs in trigger my tinnitus.

I'll do the floors next at some point. If someone has instructions/pointers for disassembly, would greatly appreciate. Like, what torque setting to apply to the front seat bolts after installing them back, etc.

So far, love my car with the dampening and sound proofing.

The Type R performed like a champ at Laguna Seca.

 

[johnloov]

Looking at Dampening on the floor metal + Mass Loaded Vinyl

 

[tibwolf]

Looking at Dampening on the floor metal + Mass Loaded Vinyl

That's a commitment for sure! If you're going to 11, I'd also look into getting the windshield replaced with one of the acoustic ones from the other Civic trims. I'm not sure if this car has double pane glass in any markets, but that could be another path forward as well.

As far as MLV goes, you might want to get a middle layer to go between it and the CLD or metal floor pan. Also worth considering lead sheeting instead of MLV to have better chances of getting everything fitting back together correctly.

https://www.diymobileaudio.com/thre...without-decoupling-layer-on-floor-pan.452568/

 

[Websitesdown]

That's a commitment for sure! If you're going to 11, I'd also look into getting the windshield replaced with one of the acoustic ones from the other Civic trims. I'm not sure if this car has double pane glass in any markets, but that could be another path forward as well.

As far as MLV goes, you might want to get a middle layer to go between it and the CLD or metal floor pan. Also worth considering lead sheeting instead of MLV to have better chances of getting everything fitting back together correctly.

https://www.diymobileaudio.com/thre...without-decoupling-layer-on-floor-pan.452568/

Lead dust is bad. Just saying. I've worked around lead for awhile doing x-rays. I wouldn't put any lead anything in my car.

 

[tibwolf]

Fairly low chance of lead dust if you’re not grinding lead to shape. There’s off the shelf product too, but it’s expensive

https://resonixsoundsolutions.com/product/resonix-barrier-moldable-noise-barrier-mlv-replacement/

 

[Websitesdown]

Yes, very expensive. Not worth the risk imo.

 

[johnloov]

Here is my floor strategy:

1) Amazon Damping - I'm probably just going to stick with Amazon Basics, it's been working extremely well at dampening - making the car feel solid, removes resonance in the cabin, including my seatbelts that used to shake, and their was a rattle around the entertainment gps screen, and that went away also. Somehow by dampening the doors, trunk, and wheel wells, it helped dampen vibrations that traveled to the center console and seatbelt.

I'll do the entire floor, and this should lower the center of gravity a tad... relatively... which should be interesting.

I think this stuff is responsible for my type R mode, becoming much smoother also. The entire chassis of the car is very stiff, and since the car is a lightweight tin can from the factory, the entire car resonates, and most likely amplifies with harmonic waves -- Now it's well dampened, as I did everything in the wheel arches, close to the suspension as well. It's really making the car well behaved.

The dampening is really doing wonders to the car in absorbing all those vibrations that are traveling through the car.

2) AuggSound 157 Mil Close Cell Foam - I used this over the wheel wells, and it was excellent and sticks very well and is very light/thin enough to fit in close tolerance sections.

I'll add this layer on top of the Amazon basics.

157mil 18sqft Roll Pack Universal Sound Deadener for Cars with Aluminum Foil Tape&Car Trim Removal Tool-Closed Cell Foam Noise Deadening Material-Heat Shield Insulation Dampening Mat

https://www.amazon.com/dp/B0BNBTSG36/?_encoding=UTF8&pd_rd_i=B0BNBTSG36&ref_=sxts_sparkle_sbv&qid=1725920793&pd_rd_w=B2nMI&content-id=amzn1.sym.8591358d-1345-4efd-9d50-5bd4e69cd942:amzn1.sym.8591358d-1345-4efd-9d50-5bd4e69cd942&pf_rd_p=8591358d-1345-4efd-9d50-5bd4e69cd942&pf_rd_r=42XY49T6R8ZD0WDBB47G&pd_rd_wg=LI3My&pd_rd_r=cca176ef-9dd0-4024-8fb6-b8acb02f9649&pd_rd_plhdr=t

3) In Sections I have more space, I'll use Acoustic foam, with dampener built in and without. If possible stuff the one with dampener closer to the firewall.

So far I've added ~65-75 lbs to the car. ( Will confirm exact totals after project is complete - I have weighted all the materials. )

After the floors, Then this project is done... I hope

I'll run some more lap times at Laguna Seca and see if my times changed at all.

Supposedly 100 lbs of extra weight is about 1/10 of second around Laguna Seca according to my instructor. Not too worried

 

[johnloov]

Looks like my wife was right.

There is quite a bit of road noise coming from the floor, and it seems Honda did put sound absorption material attached to the underside of the carpet. They put even way more in this rectangle door/hatch which reveals the chassis VIN number.

I removed the passenger side cut away, just to see while on the highway the amount of road noise under the floor carpet, and yes it's louder.

As soon as I removed this rectangle cut out, it got louder in the cabin.

When you knock on this metal, it also sounds like a tin can.

I think amazon dampening + a layer of acoustic

foam will do the trick.

 

[johnloov]

Here are some more observations...

I have driven both the new 992 Carrera/ Carrera S and Cayman S, all equipped with the same Michelin Pilot 4s's we have, and they were also extremely loud inside. Actually much louder than the type R.... I couldn't take it..

I was registering 86-89+ decibels on my test drives of those cars. ... Same as Harry's Garage and he tested both the 992 Carrera and Carrera S.

He thought the smaller wheels would help with road noise on the base Carrera, but still those Michelin P4s's create a crazy amount of road noise into the cabin.

Looks like other's have also experienced this in other cars..

After deadening the floors,

This maybe the next....

 

[Shingo Shoji]

Great thread. The sound deadening I put in my doors is helping but it's not a massive improvement. I must say that my wife's BMW really does a great job of filtering out the road noise on coarse roads but then again, it's super heavy. I'm going to try 18 inch wheels with a bigger sidewall in the future (if I can afford TE37s) and hopefully that helps too.

 

[johnloov]

There's a bit of truth to everyone you speak to... The two Audio pro shops here in Silicon Valley both said the same thing.. Sell it and get a German Car, "35 years in the business, after you dampen the entire Honda Civic tin can.. you're gonna maybe get close to Honda Accord sound level DB's )... I'm trying to prove them wrong, by dampening the hell out of this car, and it's working.. But yes a manual M2 I test drove was much quieter... but it was not as fun... especially the shifter... if I can get this thing to be well behaved... for 100lbs of extra dampening.. she'll be perfect. let's see what happens.



Road noise, you can really hear it in this video.

My car is getting quieter... Very curious what happens with the floors next

Sponsored