[Bonburner]

Originally Posted by Spankopotomous

I hate the road noise and wish for a more comfortable ride.

Back in February 19 I got my stock asphalt manual 13 FR-S with 34k miles. I drive roughly 1.3k L.A. traffic highway miles a month and I hate the road noise/ride quality. Upgrading from stock tires to 225/45/17 MPS4's improved grip immensely but did nothing to quiet road noise. Shouting to passengers or listening to the stock radio between 40-50 volume on the highway seems excessive.

I love the sports car weight and handling, it feels like riding a guided missile barreling down the 110. Now the car is approaching 60k/a major service interval. I can't help to imagine that some dynamat, sound deadening, lightweight 17x9+35's, a sound tube delete, or new bushings/window seals may be in order.

These are over exaggerations but I really believe the car can be improved to a true GT.

Has anyone built and achieved a comfortable "GT" build?

Google is your friend

That being said, the second page of that thread the guy says:

Originally Posted by nalc

It's probably not Lexus LS quiet. The real limiting factor at this point is the frameless windows. Road and engine noise are down significantly, but there's still some wind noise, and there's not much I can do about it.

I measured it around 85 dB with the app on my old phone at 65mph on the highway, and 78 dB after the sound deadening. I don't know how accurate that app is, so the numbers are probably off (I've already been challenged that there's no way the BRZ reaches 85 dB at that speed), but the 7 dB reduction is probably about accurate. Remember, it's a logarithmic scale, so 10 dB = 10 x as loud.

As a better example, I took someone for a ride who did not know that I had done any sound deadening, and he remarked that he was surprised how quiet it was. I'd certainly be up for doing an actual comparison with an accurate SPL meter, perhaps at a meet or some other event where we could compare my car to a stock car at the same speed on the same road.

As for the headliner, there is nothing securing the Thinsulate. It's just sandwiched between the headliner (which is actually quite stiff) and the roof. One nice thing about treating the headliner is that you lose the "rain drops on a tin roof" sound when it rains. Raindrops make practically no noise on the roof now.

I'll post a more detailed write up on it once I have a chance (maybe tonight), but for now the pics are available in the imgur album in the first post.

I paid about $600 for all the materials. In retrospect, my amount of CLD was a bit low (I used 45 and could likely have found room for another 5 without too much trouble), my amount of CCF was too high (I only used half of what I ordered, since there was already foam below the carpet), and my MLV and Thinsulate were right on the money.

I should also add that if you're doing any JDM interior pieces (like the kneepads or armrest), or if you're installing upgraded speakers, do them at the same time. Taking all these panels off makes those upgrades very fast and easy.