Folks, I am getting a new Prius soon and only thing I am not looking forward to is the road noise. My curent BMW 3-series registers 69 dB on the sound meter on I95 here in the NY area. Even though Prius (I rented) is same 68-69 dB - it feels noisier. Not smooth. I am wondering what it is that its bothering me. Is it the noise coming from tyres and the rough ride quality or just the fact that type of noise in Prius is different from that in the BMW (and me not being used to it) ? Anyway, I am definitely going to replace stock tyres with GoodYear Comfortreds. Next, I would like to put Dynamat Extreme in the door and floors for 8-10 dB reduction that others have reported. I am wondering how much Dynamat I will need to cover 4-doors and the floors. I was thinking of getting 36 sq. ft bulk pak + 1 door kit (12 sq-ft) for a total 48 sq ft. 24 sq. ft for the doors and 24 sq. ft for the floors. Will that be enough material ? thank you, -Sanjay
<div class='quotetop'>QUOTE(femski @ Jun 29 2006, 04:23 AM) [snapback]278507[/snapback]</div> Some people have previously measured that the floors are already well sound proofed enough. Only the doors need some more.
<div class='quotetop'>QUOTE(NuShrike @ Jun 29 2006, 07:28 AM) [snapback]278508[/snapback]</div> I looked in an old post where Tadashi measured dB drop after each step. Door - 5dB, Floor 5dB (even though its well insulated as you say), and Roof 3dB. Given the cost and hassle of roof insulation and I am not going to get it done. Floors also I am not sure about. I would like to keep Dynamat to minimum - given the fire hazard, complications in later repairs and chances of developing the rattle. May be do the tires first. Then the doors. And then see if the floors are needed. Any experience advice wold be welcome.
You will be bothered no matter what. Due to the sound being different. I started with the basic car and was bothered because I was used to a diesel engine noise. All I heard in the Prius was road noise mostly. So I insulated the doors with B-Quiet (1 damper layer, 2 insulation layers) and the noise level dropped dramatically. I then stated being bothered by the wind noise. I also use Michelin Energy MXV4 tires. Much better ride, handling, and quieter. Next I may insulate the floor a bit. I removed my seats in back recently to bring a freezer home, , so while they are out I will add some insulation. Amazing how many new noises I hear driving without the rear seats in place! Lots of metallic buzzes going over bumps! All from the metal under where the back seat goes. Every change leads to a new kind of noise to bother you even though the car measures quieter and you can hear the radio better. I don't think I will bother with the roof. Too much noise from the window glass and the gaskets to notice the roof noise much. I'd like the sound absorbing glass next but don't think it is available yet! Then maybe the roof insulation would help. Might have to seal the windows permanently up though with caulk!
Even though the current Prius model has insulation under the hood, I am sure that noise could be reduced with some of the aftermarket stuff.
I think my friends Camry Hybrid is quieter than my Prius. I haven't measured it but I have pretty good ears and it does seem quieter. If you are willing to give up some mileage compared to the Prius the TCH might be an OK car.
<div class='quotetop'>QUOTE(femski @ Jun 29 2006, 04:23 AM) [snapback]278507[/snapback]</div> Some of the difference is in the fact that you are comparing a transverse coupled 4 cylinder engine against an inherently smoother inline 6 cylinder that is linearly coupled. Beyond the obvious other differences due to the natures of the 2 vehicles; ie, the BMW most likely has a more sophisticated suspension and tire set than the Prius, where the engineering effort was expended in the HSD system.
As many of us would attest, the Comfortreads are awesome tires. But they last for something like 80,000 miles, so don't plan on trying other tires anytime soon.
Trust me -- try the tires first, then decide on the rest. I also know what a quiet car sounds like as my "other" ride is an Audi A8. The Prius with Comfortreds isn't quite as silent as the big Audi, but it is close enough that I don't plan on getting the doors or floor done in Dynamat.
<div class='quotetop'>QUOTE(Tigerops @ Jun 29 2006, 08:58 AM) [snapback]278611[/snapback]</div> Do they make them in a Low Rolling Resistance variety?
<div class='quotetop'>QUOTE(darelldd @ Jun 30 2006, 07:38 PM) [snapback]279471[/snapback]</div> Yes, they're called "42/40" Comfortreds and they're just for Prius...
...Or you could move to a state that uses rubberized asphalt, like Arizona. In Phoenix rubberized asphalt reduces freeway noise by 50% - both inside and outside the vehicle! http://www.azdot.gov/Highways/EEG/QuietRoads/faqs.asp
