langhorne_bill

This is a great and informative thread. I have a C6 Z51 3LT with MZ6 transmission that I wanted to be a comfortable cruiser. So, my first modification for noise and comfort was to replace the Goodyears with Michelin A/S run flats (for a noise reduction) along with Bilstein Sport shocks which got rid of most of the harshness. Recently, I installed a set of base C7 rims with Michelin PSS ZP which took care of any ride harshness and gave a 2 dB reduction in noise at 70 mph relative to the A/S tires.

I used RAAM Audio products (BXT II and ensolite) to quiet the interior and found that it was rather important to also do the door panels. I completed the project in several steps and kept noticing how much the Bose sound kept improving – GM and Bose must have qualified the sound system in an anechoic chamber with the engine off!!

My C6 sound level at 70 mph is now at 66 dB(A) which is now almost equal to my wife’s Malibu LTZ which is incredibly quiet at 65 dB(A). I do not have a baseline sound level for the un modified C6 as I bought a real sound level meter part way through this – my smart phone showed a 75 dB(A) prior to any modifications. The Corvette is a great car, but reducing the interior noise makes it a superb ride. I still, however, love the music of a great V8 engine and have a complete ZR1 exhaust system with a mild to wild controller that really howls when needed..

Bill

Crazy Cowboy

I somehow never saw this thread until now. Thanks for taking all the time and effort to write this up. I will definitely take note of your input as well. I've been doing insulation kits for Corvettes since the C5 about 13-14 years ago and the C7 Extreme kit is the best kit yet with the extra 'Extreme' level it has really improved the noise-cutting a lot over the already best-selling base kits for the C4, C5, and C6.

Thanks again for sharing. This is the kind of honest review that money and advertising cant buy.

Bubbletop409

That's because our governor cares more about his third world illegal buddies than he does the wants or needs of the citizens, despicable POS.

Hopper12

My pleasure. I've received a lot of help from members of the forum, and want to give back when I can. I found your kit to be very well laid out, the instructions clear, and it really made a nice difference. So much so that I ordered your kit for our new GS too. Will install it in the next couple of weeks! So, my/our thanks to you for a quality product.

FKING1

I put 2 layers of Fat Mat in my Z51.
May be over kill , but, a noticeable reduction in sound.

wlittle49

My Extreme kit from Cowboy arrives today for my C7 Stingray. Will be working on it this weekend and see how far I can get with it. Thanks to all for the pictures and other great tips. Will let you know what I think but since this is my first Vert ever I don't have anything to compare. I just did a thousand mile round trip from Chiggerbranch, MS to Dallas and back and the road conditions certainly make a difference. The older and bumpy concrete roads can get loud and the new blacktop is much better. This will give me another great excuse for a ROADTRIP!!

speedlink

Let us know. Maybe get some decibel readings before and after with top up. Thanks

wlittle49

Will do but only half of the kit came in today and I have contacted Cowboy and asked WTF? Need it by Saturday to get it going. Plus no instructions yet. Grrrrr.

The Chev

I found in my research that the point of diminishing returns on the DynaMat style sound deaden-er is 30% coverage for those that are concerned about weight above all else.

That said, in the tire area 100% coverage is not enough. On my C5 I covered the wheel-wells from the inside, but once I took the wheel liners out and added deaden-er to the inner side of those, the tire noise significantly dropped.

Michael A

Excellent write-up. Great to see some actual sound measurements with a real sound meter, too. Thanks for posting.

lennykoll

Although I don't find my 'vert to be terribly noisy, I have thought about putting a kit in to optimize it.....

Has anyone installed a kit into their 'vert (I already have made the AS tire switch when I first got the car) and do you have any
metrics to share..... thanks, LK

recentlydivorced

For reference: a 3 dB reduction is almost 1/2 the sound level. As someone said earlier sound scale is logrithmic. Per standards, 4 dB reduction of sound is half the effective sound exposure.
That is a good amount of reduction.

BLACKCREEK

RMS73

Tested the Double Extreme Insulation kit out tonight. Driving in Sport Mode like normal.

Before the DEI kit, if I remember correctly driving on the local interstate at 70 mph I was getting around 87 dba on older asphalt. I could not find the paper that I had recorded the readings on so I have to use my old memory. I do know that the radio volume would be around 10-12 on the highway and at 6-8 for around town.

Tonight, driving at 70 mph on several year old asphalt road surface;

The radio level was at 5

My wife and I had conversations at normal talking volumes

dba meter was registering 73; 78 on concrete surfaces at bridges

On new asphalt the sound level was 68 dba

On very old asphalt the sound level was 77 dba

From my testing after installing Crazy Cowboy's DEK:

Driving at 55 on new asphalt - 65 dba, older asphalt was 68 dba

The radio level was at 3

Driving on the back road home at 35 mph I couldn't hear anything. Even turned the radio down to 2.

Previously the radio was never below 6 even at 35 mph on good, older asphalt. Also conversations required an elevated speaking volume.

Finally did hear a little wind noise on the interstate. When accelerating I could still hear the sport mode exhaust, not as loud but still could hear it with ease.

hkfan

Has anyone paired the double extreme kit with CLD tiles? I’m looking for vibration and sound deadening.

gpotski

I used dynamat extreme as the base layer. Bought the block-it as well, and added a Lloyd's cargo mat to top it off.
It all helped a lot, but I didn't do any measurements.
Subsequently went to the Michelin A/S 3+ ZP tires with additional improvement over the OEM tires on my 2015 Z51 coupe.