Cabin noise

cmdjing

If you have the sport package with the 19" wheels, you have the Bridgestone Potenza RE050A's. According to tirerack, they are in the middle of the field of "max" performance summer tires and the road noise is the same. If the noise is really a concern, switch to the Continental extreme contact DW's which are significantly better noise wise than any other performance tire.

Dpeters

I just put down the Second Skin product in the rear portion of the car and it made a little difference, but none to justify the amount of labor required to put it down. FYI: Pulling out the molding and trim in the back of the Z is a breeze. The only trick is learning where the pressure clips are so you pull in the right place.

I think I bought the Damplifier Pro 20 sq ft pack and still didnt have enough to get every little nook of the trunk. If you plan on doing the front of the car, I'd suggest much more than 20 sq ft.

NOTE: I'm not dissing the Second Skin product, I just think more sound comes from the front of the cabin and doors than we think.

Guard Dad

Dpeters,

Which "Second Skin product" did you use? Was It the Dynamat Exterme type product or was it Luxury Liner Pro? If it was Luxury Liner Pro did you follow their recommendations to install the Dynamat Extreme (sorry I can't remember the name of Second Skin's comparable prpduct, is that the Damplifier Pro, an asphalt and aluminum sandwich?) before installing (or did you even use) the Luxury Liner Pro?

I've done Dynamat Extreme in the hatch and doors and it makes a nice improvement but I'm ready for the next step which would appear to be Luxury Liner Pro so I'm very interested in the specifics of what you've done and the results obtained.

RiCharlie

Thanks for this post.. i got my Z about two weeks ago..my first one and the noise really killed the enjoyment of it.. very upsetting. So i went to the audio store and they told me they could dampen the sound but I would have to wait a bit over a week for the job to be done.. since then I have been anxious and wondering what the result will be... I am sure you can understand.. so when you posted this, this comment really helps my psyche a lot!! Thanks so much!

JACKPAC

Glad to contribute

Guard Dad

Jackpac, which Second Skin product(s) did you use?

Dpeters

I used the 20sq ft pack of damplifier pro only. No supplimental products were used as I didnt want to add a massive amount of weight unless I could help it. I think I'm going to order more of the damplifier pro and possibly some of the secondary additions that compliment it to ensure I have a "sound" install (pardon the pun).

chops

i drive a 2006 corolla as a daily driver and the road noise was killer with high performance tires and lowering springs (compared to the cheapo tires it came with). i coated all the wheel wells as well as the doors and road noise was reduced dramatically. although it was pricey, i think i paid like 60bucks for a gallon of the stuff. im thinking of using the leftovers to do the trunk area once the weather warms up (much easier to apply when the weather is warmer)

Guard Dad

Dpeters,

Just checked, Damplifier Pro = Dynamat Extreme. It took me 36 square feet to do the doors and hatch, no surprise that 20 square feet left you a little short. The noise reduction was nice but only made me want more.

I was wondering just how bad the noise from the hatch still was and what I could do about it, so a couple of nights ago I packed the hatch and the passenger footwell with blankets and fabric covered patio chair cushions and then ran some errands.

AND THE ENVELOPE PLEASE! Cushions in the passenger footwell had little if any positive effect. Packing the hatch area made an real difference and this was done with Dynamat Exterme already in place. You still clearly hear the changes in the pavement but the pebbles-on-sheet-metal sound that was so noticeable when stock had diminished enough that it wasn't an issue for me. I also found that I needed to lower the volume on the radio, the quieter interior made the old volume setting seem too loud. Not luxury car stuff but trending in the direction of Grand Tourismo.

The take away for me was that the hatch was still the major noise source and that I should concentrate my efforts, for now, in that area. Since I don't want to drive everywhere with a hatch area loaded with blankets and pillows (what might people think, I'm a little old for sleep overs!) my next move is probably going to be overlaying the Dynamat Extreme with Luxury Liner Pro. As you might guess I'm interested anyone's experiences with Luxury Liner Pro or similar produces.

Parrotguy

I have a 2010 roadster and I do not have a problem with interior noise with the top up, and I don't recall seeing any roadster owners complaining about cabin noise. In a way this seems backward - cabin noise is something many convertibles have, and in car reviews of rag tops they will always comment on interior noise. I think that this re-enforces the conclusion of Guard Dad that most of your noise is coming from the hatch area. The compartment in the Z that holds the top in the down position is enclosed, so sound doesn't come forward.
Nissan uses a double fabric top to reduce noise like the Z4 has, and it reduces noise from the outside.
Ironically the disadvantage in the roadster is that the "sub woofers" are mounted behind the top compartment and a lot of bass doesn't make it through. It would sound a lot better if those speakers were mounted right behind the cabin, but my guess is there is not enough room there when the top folds in.

RiCharlie

Well what you say makes lots of sense. I am not asking for Lexus quiet but one reviewer compared the noise on some pavement to a cement mixer and I have to agree! Meanwhile, I am writing this as I am getting ready to deliver my car to the audio installation store where they will add this sound dampening material to the hatch area. I will let you know but meanwhile thanks for the advice..

Jquad

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LunaZ

Get an exhaust and then you won't notice the road noise.
You also get the benefit of added performance and a small weight saving!

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RiCharlie

Well here is the report on the noise reduction efforts of yesterday. It added fifty pounds to the car and lightened my wallet by $800 and as far as I can see did nothing.. absolutely a waste of time and money..
I have to believe the material did something but the result was nothing I could detect.

I think part of the problem is that the noise is a bit hard for me to accept coming off a Honda accord, but I am getting used to it. It did not help that the first day I had it we took a trip to Cape Cod and met with several miles of really noisy surface highway.. that is like riding on a washboard and so things got off to a bad start with my wife the very first day... and this waste of money on sound dampening isnt going to make things better..Next time I am going to change these tires as that is the only reasonable next step.
But with a little getting used to, and accepting the fact my wife has a different view, I am very happy and excited about this car and look forward to many miles of enjoyment. Thanks for everyone's help.

Guard Dad

Sorry to hear of your disappointment with the upgrade. I'd like to offer the following for your consideration.

Noise can be a real problem and simply turing up the radio or getting a loud exhaust in no way addresses the very real problem of noise fatigue and it's negative effects on driver performance, fatigue and comfort. Having said that, the 370Z will never be a quiet car unless extensive measures are taken, measures that most owners would feel compromise the sports car experience that the Z offers.

Based upon my modest experience and the experiences of several others on this forum you should be able to achieve an acceptable sound environment without draining your wallet.

The most common first step is the application of a Dynamat Extreme type product on the hatch floor and fender wells in the hatch area. Often included in this upgrade is the application of the same product on the doors, as much for improved speaker performance as for sound reduction. The widely available technical information advises that the Dynamat is primarily for reduction of sheet metal resonance (and noise suppression/reduction to a significantly less extent) and really needs to be applied to only about 25% of the area of concern. Then the entire area, including the Dynamat, should be overlaid with a layer of sound absorber/suppressor like Luxury Liner Pro. In reality, most forum members, myself included, simply buy a big box of Dynamat and cover everything in sight with the Dynamat, check the 'Mission Accomplished" box and move on to the next mod. This might not be the sophisticated approach but the benefits are real, it's simple to do, the sound levels are down and the harshness of the sound is reduced as well. If you drive with the windows open this may be all you need. Why? Because the altered acoustics (the cockpit is no longer a sealed enclosure) of the interior change, favorably in my opinion, the character of the noise and no, the improvement isn't simply the wind noise masking the cabin noise.

For me, I wanted greater improvement. Shortly, I will be installing Luxury Liner Pro over the Dynamat and I'll post my results here as soon as possible.

I suspect that a lot of the road and tire noise is the result of the suspension bushings installed by the factory. My guess is that they are on the firm side to accentuate Z's crisp handling, a choice which in my opinion is appropriate for this car. However, firm bushings often transmit significantly more noise than soft bushings. An aside, a number of years ago I upgraded to a urethane transmission mount on 99 Camaro SS M6, I was blown away! What a noise! No joke it sounded like the transmission was actually IN my brain. Needless to say I reinstalled the stock mount. Different tire brands and types can have a similar impact on cabin noise.

You said you noted no improvement after the work was done, I am curious as to exactly what was done, perhaps you could elaborate. If you can still clearly hear every pebble and bit of sand hitting the underside of the car it would make me wonder if they did much of anything to the car. Dynamat is a very popular choice here, and for good reason, however the application of sound deadening mastics have yet to find many fans here. Do you know much about the products that were used? If they had just done the 100% Dynamat treatment (material cost for 36 square feet is about $140.00 from Amazon) I would have expected you to post that you noted a significant (not dramatic) reduction in noise levels since numerous other posts, and my own experience suggest that this would be the expected result. Undercoating the fenderwells hasn't been shown to be especially effective but sound absorbers like Luxury Line Pro do seem to be effective. Application of these products is not difficult but requires a certain attention to detail to get good results. Dynamat installation is well documented on this forum, not so much information is available on Luxury Liner Pro, acoustic mastics and undercoating in the 370Z. I plan to add to that knowledge base in a few days.

If you're interested, you might duplicate my previously mentioned experiment with the blankets, pillows and cushions PACKED into the hatch area. If you feel that this doesn't yield an acceptable improvement, the Z may not be the car for you. Short of loading 100+ pounds of sound deadeners in the car, I don't expect a sound environment dramatically better than I achieved with the Dynamat and the blankets etc. in the hatch. My pending installation of Luxury Liner Pro is simply my attempt to reduce the sound level to that achieved with the blankets without actually having to drive around with a car full of blankets.