Particularly with the hearing aids that I wear, the noise inside the C7s that I have demo'd is so loud as to discourage me from buying one. Would all or any of the following things reduce the interior noise to anything approaching that of a conventional non-sport car? 1) Getting a 1LT with basic mufflers and exhaust on the rear corners (rather than centered like on the Z51s)? 2) Getting new after-market quiet mufflers? 3) Installing interior sound insulation? 4) Getting softer and/or narrower non-run-flat tires? Anything else?
I realize that this is not an issue that appeals to most Corvette owners, but please don't respond just to ridicule me or tell me to get another car. I don't want to have to do that if I don't have to. Thanks.

 

I don't know if there are muffler options that would help the cabin noise. I can't imagine how they could be re-routes to the sides? Also, I don't think tires will make a lot of difference. I did add sound deadening insulation under the carpet in the back. It helped some, but not as much as I had hoped. Wish I had a better idea for you, but I don't think you can successfully deaden the road noise all that much. I don't mean to be making a stupid suggestion, but maybe taking your hearing aids out (or adjusting them differently) may be a solution. I guess I am fortunate enough that the noise doesn't affect my hearing aids too badly. Good luck on your solution.

 

If it's the performance exhaust, you can leave it in tour or silent mode. The sound insulation behind the seats and the cargo area will help with the road noise. The C7 will be worth the extra effort to make right for you. Good luck!

 

Thanks, Digfoot.
If I take out the hearing aids, I can't enjoy the sound system. (But, for the life of me, I can't see the point of a premium Bose system in a car this loud anyway.) Re my question about the exhaust on the sides -- I mistakenly thought that the basic 1LTs did not have the 4 in the center. Maybe I'll just have to accept the noise or forget it.

 

I think you demo'd a car with the performance exhaust. Good news is there is an option to turn it off. FYI all models have the 4 exhaust pipes in the middle. IfI this doesn't work, you can always turn down your hearing aid a bit. Don't let this prevent you from getting a vette-the car is relatively quiet with the performance exhaust off- or just don't get that option.

 

I wonder if I just throw a thick down comforter back there on my next demo, if that will give me some idea if commercial sound insulation would help?

 

Maybe I should just wear sound-deadening headphones plugged into the sound system on trips -- although that might be too dangerous.

 

If the car you drove was a coupe and had the NPP option that was set to track mode, yes it's loud. Much quieter in touring or stealth modes. The other thing to consider, the convertible is actually quieter. The cargo area is sealed off from the main cabin.

 

You can eliminate some of the noise by putting in Fat Mat sound deadening material behind the seat and in the " trunk". There are posts about it in this section. Also, putting a non run flat tire such as Continental, Hankook, Dunlap, or one of many others will help with road noise as the sidewalls are not nearly as stiff, resulting in a softer ride and less noise. Plus, a car with the standard exhaust is far quieter than the NPP exhaust. Lastly you could just turn up the radio. Or all of the above.

 

Just buy crazy cowboys insulation kit. He personally instslled mine huge difference.
His company is exoctic vettes. Great kit, makes car very enjoyable.

 

A few things...

• The exhaust system is in no way tied to 1LT vs. 2LT vs. 3LT. It's determined solely by whether or not the car is equipped with RPO NPP, the dual-mode performance exhaust system. NPP is automatically included with Z51 and is available as a free-standing option on non-Z51 Stingrays.
• Whether NPP or standard exhaust, the four pipes exit the car in the center rear. There are no Stingrays that leave the factory with corner exhaust.
• There are several driver-selectable modes for the NPP exhaust system including "stealth" which keeps things relatively quiet all the time.

 

Hmm... The convertible, eh. Hadn't thought of that.

 

Where is crazy cowboy located? Did you get the "extreme" kit? Is this something I could install myself?

 

He is in central Florida. http://www.exoticvette.com/insulation%20c7.htm

 

All good suggestions. I'm pretty sure most of the noise at hwy speed is road noise, not exhaust. And I'm willing to put in as much sound deadening as it will hold. I wonder if I would need new wheels to accommodate quieter tires. BTW, I'm in Austin, too.

 

I've been very interested in noise reduction, and have spent a lot of time reading threads on the subject. I got my C7 mainly for fun road trips. Here are my observations so far:
* Lots of members have installed the under the carpet solutions, and most say they got 'good' or 'really good' results. However, I haven't seen any posts with actual measurements.
* I have a '15 Z51 coupe and drive it in sport mode most of the time. At highway speeds, none of the interior noise is from the exhaust unless I'm accelerating for some reason. It's all road noise.
* I just went out on the freeway with my son, and measured the interior noise with the windows up at 75-80 mph at a constant 79-80 decibels. I'm going to order and install the 'extreme' kit, and go back out to the same stretch of freeway and measure the after results. If I don't get at least a 4-5 decibel improvement, I'll consider it a waste of time and $. I'll post the results. (If anyone knows of before and after measurements I'd sure be interested).

All this said, this is my first vette, and I absolutely love it. An awesome machine. And I would agree with those who said the vert is more quiet than the coupe - at least to my ear, but I never measured it. I needed the coupe for the luggage room for road trips. Good luck!

 

It makes a lot of difference in the road and exhaust noise when you put in sound deadening.
Won't help wind noise, but the C7 is a quiet car and more so with deadening material.

Anxiously awaiting you decibel numbers!

 

buy a caddy

 

You just gave me a great idea. I have a '14 Caddy too - I'm going to measure the decibels in it too and see how it compares to the 79-80 I just got from my vette............I'll be back in a while.

 

Since it was a Saturday, I decided to install Fatmat Sound Deadening (Rattel Trap Extreme) material. I ordered 50 sq ft from Amazon.com with a cost of $109.00. It was delivered mid week, so I thought today was a good day to install it. I own a 2015 C7 Coupe and found the interior cabin to be noisey. I wanted to reduce the noise from the tires.

I removed the side plastic panel that covers the wheel wells, removed the carpet and tie downs then went to work. It was determined that the hatch area flooring is all plastic, no metal floorborad, which I was quite surprised. I thought perhaps it might be a lightweight aluminum to match the chassis, but it wasn't. Also the covers to the wheel wells are also all plastic. How cheap can GM get!

I also pulled the one piece carpet panel that sits in back of the driver and passenger seat exposing the back panel. This panel was a thin metal. I did double thickness on the sound deadening material in back of the two seats.

It took about 6 hours total for the install and replacement of all side wheel well panels inside the hatch area, reinstall the hatch carpet, reinstall the cabin carpet in back of the seats. The hatch side panels (plastic) just snap out and back in with clips.

Here's a few photos of the install and the end result.

Ok......I test drove the C7 after I installed the sound deadening material Fatmat (Rattle Trap Extreme). Bought at Amazon.com. There was no elimination of the sweet exhaust sound from the NPP. It was great. Interior noise from wheel whine, and spin was reduced significantly as well as general road noise from the road surface. While I can't put a percentage on the noise reduction, it was very clear there was a major improvement. The audio system sounds great, and the interior cabin is much more comfortable from a noise standpoint, and conversation with any passenger will be easy to hear.

I have no regrets spending hours completing the project and highly recommend this modification to reduce overall road and tire noise within the C7. For the cost of $109 for 50 sq ft roll, it was worth every penny spent, and I even have some product left to complete a DIY project on my Jaguar XKR Portfolio Edition trunk area.