Maxie2U

OP, outstanding write-up and skillfully articulated. It clearly came down to the noise ruined the driving experience for YOU and that’s what counts because it’s your car. And the cost of material was far less than I thought it would be. Then again you didn’t break or crack any of the trim you removed because that would be expensive!

I’m happy you were able to find a solution and had the fortitude to solve the problem with an innovative sound proofing solution. Clearly it was a lot of work but it sounds like it gave you the desired results.

Did you have figment issues reinstalling the trim, carpet, center console, etc after laying down the CLD tiles plus neoprene foam and the mass loaded vinyl?

I took an easier route that I’m sure did not deaden the sound anywhere near your results but given the road noise is not a big deal to me it was not worth the effort you put in. I simply laid down the BlockIt sound deadening mat in the hatch area and laid down BlockIt material under the carpet behind the seats and up the backside behind th3 seats. I did not (yet) cover the rear wheel wells but need to since that is now the main source of road noise.

And I don’t find I get a lot of heat through the firewall. I do get a lot of heat from the transport top but resolved that by installing a heat shield on hot days.

I hope you get to now enjoy your GS as it is an awesome sports car.

tome

This should be added to the sticky section!

Maxie2U

red62vette

Sounds like you did a really nice job and are happy with the results.

I’m not dissatisfied with the noise of my GS. My prior 335i was louder, and the M4 I almost bought was far louder. I also drove in my colleague’s five year old Carrera and it was loud and rattled like hell. The only thing I plan to do is ditch the run flats, which in my experience makes a big difference.

bjones7131

Great write up. I too hate the road noise on my 17 GS. I took the less aggressive route and put down the LOWES insulation foil product in cargo area and behind seat and under seat on top of the carpet, on top of that i up down 2 black shipping blankets from HF and finally put a GS lloyds logo carpeted cargo mat. Didn't want to rip anything out and you would never know it looking at the car. Reduced the noise quiet a bit. Happy NY to all.

Kevin A Jones

I test drove 2017 GS and Z06 Coups prior to purchasing my GS vert and while I wasn't really concentrating on vehicle sound, I feel if it was abnormally and/or disturbingly loud I would have picked up on it. I mean, in my experience, high performance sports cars are typically loud from both engine and road noise perspectives. 911's, Lambos, old C2-3s are especially noisy.

Perhaps if I were exposed to a C7 Coup on a daily basics I too may be tearing my brand new interior apart as well.

Evident from this thread, noise is a problem for quite a few coup owners, one would expect GM would add more sound insulation.

red62vette

They need to trade off cost, weight/performance, and noise. I think Chevy did a good job, all considered. If the car were heavier or more expensive, folks would complain.

JerryU

^^^
100%! I am guessing that the new mid engine Caddy version, which is supposed to precede the Chevy C8 Vette by 1 to 2 years will be quieter.

They will no doubt do the job right and use appropriate insulation for the Bang & Olufsen 18 speaker car stereo to help justify the high price! Probably will have all season tires as well.

Many Caddy owners don't care about price, in fact probably like a high car price to keep out the riff raff!

They will no doubt have other luxury items you'd find in a Rolls Royce so the owner's can justify paying the higher price than the Vette version! In fact for some who live in CA and OR perhaps they would buy if it didn't have any animal products, like leather seats. Just pay Gucci to use their logo on cloth seats so their friends will know the vinyl is not real leather!

red62vette

How much do you think it would do to insulate just the hatch area, under the rear carpet, and the wheel wells?

DickieDoo

Yeah, most of the unwanted noise i found to be tire noise. I unfortunately traded my car before i did this installation.

There was another post in this section titled "anything that is worth doing is worth overdoing" and that person pulled off the rear inner fenders and applied the dynamatt to the back side of the plastic liner and inner fender.

Your post is also quite extensive and for those that complain you added too much weight, most of us can probably need to lose 20-30 lbs so that would make up for that !

Anything that make the care a better driving experience for "you" is worth the effort!

JerryU

FWIW, not as much as the thin aluminum behind the seats and the driveshaft tunnel. The rear hatch is plastic but would think insulting under the plastic inner rear wheel well over the inner wheel well would be logical. Tires ar a significant source of noise.

Above is a guess but others have put insulation under the rear carpet and not reported much difference. Some have presented before and after dB measurements.

Sandyman

OP, great write up! The wife and I enjoy long trips in our 2016 Sting Ray and I really do not like tire noise for long periods of time. Consequently I took a route very similar to yours. One difference is I only treated from behind the front seats rearward. FYI, here is a post I made:

https://www.corvetteforum.com/forums...long-post.html

I found that once getting the car opened up, I was motivated to do as thorough a job as I could. Looks like you did that and more!

G8R-Vette

Maxie2U

I soundproofed from just behind the seats to the rear end, except for the wheel wells. The remaining noise is coming from...the wheel wells!

So if you do only one area make it the rear wheel wells.

red62vette

Would you mind posting how many of each type of insulation part you used?

jimmbbo

Holy attenuation, Batman! Nicely done, and terrific writeup, op!
Since I use the car for touring and cruising, we share the same irritation at the noise levels generated under certain road conditions, caused largely by the chosen tires, and the their proximity to the cabin, exacerbated by the drum head that serves as our "cargo area" that magnifies the noise caused by road joints or bumps.
While not nearly as extensive as your acoustic treatment, nor likely as effective, I dropped in a set of Block It sound mats (cargo area plus one behind each seat) in my C7 Stingray coupe, and using the Decibel X Pro app, measured 2 - 5 dB lower noise level which is noticeable, but most importantly was cutting down the reverberations from the cargo area floor and the noises generated by road joints and seams... The 'Vette is now about as quiet as my '11 Mustang GT 5.0, my previous "touring" car...
I highly recommended them for their ease of application and ability to reduce cabin noise.

Hollingswerth

Thanks to Wikipedia: Lotus founder Colin Chapman's most famous quote is "simplify, then add lightness."

Locally, a good car audio shop would be my guess...however, I would make sure they had a lot of experience with C7s and was familiar with the trim clips/removing trim pieces - last thing you want to do is replace a bunch of trim pieces or have loose trim due to missing clips.

In an ideal scenario, you could see if the guru himself, Don Samborn and Sound Deadener Showdown would do it for you. They are located in Manchester, MD...but I don't know if they actually do installs. I'd imagine if they did the job for you, you'd have the best soundproofing job possible.





In my write-up, I noted under the MODIFICATIONS section that I did the floor of the rear hatch area differently, and let the OEM padded rear carpet serve as the neoprene foam isolation layer. The actual plastic floor of the rear area has too many raised up indentations, ie, it is not flat. The padding attached under the oem rear carpet has mutiple cutouts to allow the carpet to ultimately lay flat. If you try to do CLD tiles, Neoprene foam, MLV and then the oem carpet on top of all that it will be way too thick and the carpet won't fit under the trim pieces on the sides and rear. So, that is why I layered the products on the floor of the rear hatch in the order that I did

The rear wheel wells are covered in CLD tiles, then Neoprene foam, and then MLV on the top layer. This all fit well under the trim pieces covering the wells.

Up front, CLD tiles, neoprene and then MLV all fit fine beneath the oem carpet.....this includes under the seats and foot area, under the transmission tunnel carpet, under the trim on top of the trans tunnel, and in the vertical carpeted area behind the seat backs.



It is amazing how it does make the car feel tighter.

I also had a 335i.....a coupe, was pretty heavily modified....ran JB4 Map 5 with flex fuel - 29% ethanol most of the time. Was running 275/35-18 Supersports on rear. However, I kept the stock exhaust and just did the "golf tee" mod (to keep both sides open 100% of the time.) To me, the BMW seemed far more quiet and refined.



Even if you only do the rear and the rear wheel wells, you will be very happy! I know for a fact it will make a huge difference. See, I did the whole rear hatch area/wheel wells first, as sort of a trial/test. The rear area seemed to be the lowest hanging fruit, and if I didn't get the results I wanted, I would just quit there. After doing it, I was so blown away with the results that I then decided to go whole hog and do the front the next weekend. Bottom line:doing just the rear will make a significantly noticeable difference.



Insulating under the seats and floor mat areas seemed to reduce the vibrations coming into my body and make the car feel more solid, refined and tighter.





I did one big product order from SDS with the intention of doing my GS completely and then doing less extensive soundproofing on my wife's car and on my brother's car....so I don't have the exact amounts I used.

However, here is a fairly accurate approximation of how much product my entire Grand Sport took:

75 CLD Tiles
10 Linear feet of Plain MLV 1/8" 1 lb/ft² 54"
3 Linear feet of Foil Faced MLV 1/8" 1 lb/ft² 54"
1 1.5" thick piece of Hydrophobic Melamine foam - 1.5"x24"x24" (4 ft²) piece
1 3/4" thick piece of Hydrophobic Melamine foam - 3/4"x24"x24" (4 ft²) piece
3 Sheets 1/8"x36"x54" Neoprene/EPDM Closed Cell Foam
10 Velcro® Strips, Adhesive both sides - 2"x4"
1 8 oz can of HH-66 Vinyl Contact Cement
1 Marshalltown 2" Maple wood roller

4GS7

Wow. I wouldn't have the resilience to tear out my entire interior, but this is a hell of a project. Bookmarking this for my eventual C7 purchase.


Convertibles don't have a big hatch echoing all that rear sound and projecting it forward.

Zymurgy

Link added to the DIY, FAQ's, TIPS and Announcements sticky thread

fsvoboda

Wow, talk about over-achievement! What a great job.

I did the quick and dirty version, which was Hushmat on the vertical surface under the carpet behind the seats, and MacNeil Automotive floor liners over the rear carpet and replacing the floor mats, and found that tire noise (most annoying) was cut a lot. I may do more after driving some more in the spring and summer.