Cabin noise

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.

RiCharlie

Thanks for your very thoughtful response. I tried the blanket idea and it worked! FYI I am returning to the audio store tomorrow and something is going to be done because I am pissed!!!!!!! I located a dynamat dealer and will see them tomorrow. Thanks again so much!!

Smallywood

I'm interested how this will go since they already have your money. Good luck as I'd expect little motivation to do anything for you.

__________________

RiCharlie

Just got a letter from VISA.. they have agreed with my claim and are withholding payment.. good reasons to use credit cards!! Thought you might want to to know..Meanwhile I love this car now and the noise issue is a thing of the past.. Rough start but very happy ending..

Diesel370

I think alot of you guys are taking the wrong approach here to reducing road noise thus not getting the desired results. Basically you've been falsely sold that lots and lots of vibration dampers will reduce noise. A vibration damper such as Dynamat/Raamat/Second Skin/etc only purpose is to control resonance in a vehicle’s panels NOT reduce noise. So don't expect to cover your entire vehicle in a vibration damper and expect to cut a noise. If you are wanting to reduce overall noise in the Z you are going to want to also add a close cell foam and a Mass Loaded Vinyl to really reduce noise in the car. To get best results you'll not only want to do the trunk but also the floor boards and doors with a Mass Loaded Vinyl. The Z comes with very little sound deadening material to begin with so applying 25% coverage with a vibration damper with a closed cell foam with a Mass Loaded Vinyl on top will reduce road noise in your Z. Companies like Second Skin and Dynamat do sell these MLV's but they are extremely expensive.

Guard Dad

Hopefully the audio folks will make it right. If they surprise everyone by pulling back the carpet in the hatch to reveal a full Dynamat job (I would be surprised considering your reaction to their work) your next step would be to wait and see how my Luxury Liner Pro works out. If it works for me it should work for you.

One bit of very good news is your positive response to the "blanket" test. This suggests that a solution to the problem is possible. I suppose that this is where some wise a** posts the following: "Problem solved: "The big Blankets-R-Us sale at the mall, the new hot mod for the 370Z".

Happy Motoring!

Guard Dad

Ok, I just finished installing the Luxury liner pro and here are my thoughts:

Phase one:

Installed 36 square feet of Dynamat Extreme on the doors and hatch.
Cost: $140.00 from Amazon.
Weight: About 20 pounds.
Results: Significant noise reduction, the harshness of the noise significantly reduced. Tire and road noise significantly reduced, and the feeling that you are able to determine the exact composition of every road surface by it's overpowering sound is significantly moderated. The sense that you can hear EVERY grain of sand and every pebble that hits the chassis is almost gone.
Bottom Line: Great bang for the buck! The weight is not excessive considering the positive result. Probably good enough for most owners.

Phase two:

Installed about 20 square feet (2 1/4 panels) of Second Skin Luxury Liner Pro.
Cost: About $130.00 including shipping and a can of spray adhesive.
Weight: About 25 pounds.
Results: Additional noise and harshness reduction. Sand and pebble noise is gone. Changes in road surfaces can be noted but they are no longer annoying.
Bottom Line: Provides an extra level of refinement. Noise from the rear is no longer an issue, most noise is now from the front of the car. A moderate low frequency resonance/rumble over some road surfaces is now noted from the front of the car, apparently it was previously masked by the noise from the rear. It's not especially objectionable but it seems a bit out of place in the now, quieter cabin. I could have been very aggressive and installed even more material but I was reluctant to add any more weight. I think that most of the benefit can be obtained with two panels applied to the hatch floor and the wheel wells, about 80% coverage. I skimped on the rear wall of the hatch and I don't think it had any negative effect.

Notes:

Dynamat is fairly thin and easy to work with but in this application it goes on just about everything (about 90% coverage) so it is slow to install (about 8 -10 hours but I'm sure I could do it in about 1/2 that time now that I've done it once) the many pieces needed to do the job.

Luxury Liner pro is thick and heavy and not that easy to work with but I didn't try to apply it to every nook and hollow in the hatch so it actually went in fairly fast, about 4 hours. Avoid gaps wherever possible. Reinstallation of the trim panels is not going to be as easy as normal, I trimmed about 3/8" from the bottom of the styrofoam blocks surrounding the spare and it was still a tight fit to get trim panels back in place. Due to the bulk of the Luxury Liner Pro I had to pass on reinstalling the retainer buttons that the factory uses to secure the styrofoam blocks, they stay in place just fine without them.

More stuff:

I call this Chicken Soup because as they say "It couldn't hurt": After the original Dynamat I had some short pile (1/4" prox.) indoor outdoor carpet left over from another project so I applied it over the floor of the hatch and I stuffed some hollows behind and below the seats with polyester batting (basically pillow stuffing) and applied some of the Polyester batting on the backside of the hatch trims with spray-on contact cement.

Lay a thick soft blanket over the perimeter of the hatch opening to protect the paint from scratches. No watches, rings, bracelets, belt buckles, button front pants or pants with rivets, your paintwork will thank you.

Luxury Liner Pro is a two layer product. The soft side (feels like Temperpedic mattress foam) faces the body, the firm side is a dense vinyl and faces the interior. The material is bonded to the body with spray adhesive, one can seemed to be more than enough.

I found myself wondering if 3/8" rebond carpet pad could be substituted for Luxury Liner and still obtain most of the benefits, for those on a budget it might work, who knows?

Well that's about it.

boomboom

it takes that long to install dynamat!! damn! is there a sticky on doing this yet?

37Z

See SilNik's video sticky located in the audio section.

ocfoilist

I'm afraid I don't really understand the logic that this kind of ambient noise is a positive thing and that people shouldn't be interested in sound dampening their Z's. While I agree that the sound of a beautiful engine or an aggressive exhaust can be pleasant to hear, I don't think the majority of Z owners relish the sound of tires slapping the pavement. To me, tire roar is an unpleasant sound that makes it hard to have a conversation in the car or listen to music and after a 6 hour road trip, it can get pretty irritating. And let's be honest, it's not rocket science to make a quieter cabin environment.

To that end, it isn't particularly difficult to install sound dampening material, nor does it add an excessive amount of weight to the car. Adding Dynamat to the cargo area, floor and doors added a whopping 30 lbs to my 3,200 lb vehicle. Adding my weight pushes it up to almost 3,400 lbs and I can't see how 30 lbs is going to make any significant difference to the performance. I track my Z fairly regularly and I had it on the track both before and after the dampening. I felt absolutely no difference and would be very surprised to find any objective research that shows 30 lbs. slowing the car down enough to feel.

I also don't think that putting a bit of sound dampening material takes away from the "sports car" feel of the Z. I intentionally did not dampen the firewall and so I can still hear the engine, which is nice. Although the dampening did not eliminate the road noise, it did help to reduce it. It's a shame that Nissan chose not to add ANY dampening material to the vehicle. Regardless of a person's individual tolerance to this kind of noise, the road roar clearly irritates a large segment of the Z community. Given a choice between a 370 with no dampening and lots of road noise and a Z that is 30 lbs or so heavier but has less tire roar, I'll take the second option any day. I can't hear the road noise on the track, but my Z is also my daily driver and that accounts for far more time in the driver's seat.

__________________
Proud owner of a new 167.2 inch, 3278 lb baby Z!
Stillen CBE & G3 Intake // Stillen Lightweight pulley // Stillen Oil Cooler // Goodridge Braided Stainless Steel Brake Lines // ACT HDSS Clutch& Alum Flywheel

Guard Dad

ttt

Guard Dad

By the time you remove the trims, install the Dynamat, and reinstall the trims the time starts to add up. There are several good threads with photos that cover Dynamat installation, usually in the DIY or Audio sections. First time is slow second time is fast.

RiCharlie

Just to let you know.. This matter of the money I paid for the installation of whatever it was that did nothing, is now in dispute and Visa is withholding payment., I have a Nissan technician who has written a letter saying there was no noise reduction.
Meanwhile, I have an appointment Friday with a guy who does this kind of thing all the time including very high end cars. He looked at what had been done and tells me he can do the job correctly, for a lot less than what the other guys charged. Will let you know Saturday.

RiCharlie

Well today I got the car back and things are fine! They found there was no.. NO.. sound dampening in the doors and so they added some and also added some to the area below the glass in the back.. the result is a a great reduction in the high frequency noise and i hear more of the deeper sounds of the motor..Like the purring of a tiger ready to spring followed by a full throated attack!!! Very good job..I have found that most of this noise occurs in cars with the Sport Package because of the larger tires..
Anyway .. all is well now and I might add that the guy that fixed it said he has driven many many exotic cars because a very high end dealer has him do work for him and he told me this Z compares favorably with Porsches costing 90K!!

The key is the upper area of the hatch and the doors... I could still do more but right now I am just going to relax and enjoy the car..

and one other thing to all the guys on this post..this is totally off topic but I will say it anyway.. get yourself a PSA test.. Prostate Specific Androgen.. An incredible One in seven to one in three males will find they have prostate cancer.. I figured it would never happen to me but it has..but I am lucky because i detected it early and am a survivor..if I had waited until I had symptoms I would be dead after two years of misery.. It was when I got this disease and was lucky enough to get it treated early that I said "F" it!! I am buying this car. NOW and that is the "rest of the story!" ..Perhaps I can save just one life by posting this...Spread the word..