Objective analysis of cabin noise solutions
 

There is general agreement that the 370Z is noisy. The sport package versions appear to be the loudest. There also is agreement that reducing the road noise would be a good thing.

Several solutions have been tried by members. Members report different results applying the same solution. Since "loud" is subjective, I suggest that members preparing to perform cabin sound reduction provide some objective data.

If you have an iphone, a droid, or a Windows phone, you can download an app (99 cents I think) for measuring sound levels. Since we are interested in "before" and "after" numbers, we are not really concerned with how accurate the absolute values are; just the difference between before and after.

How to do the measurements
Download the app and familiarize yourself with how to use it.
Before you install the material:
Find a road you can easily reach that you consider noisy. Measure the sound level between two points you can find again. Drive at a constant speed. Note that level. It should be in db (decibels).

After the material is installed:
Return to the exact spot you measured the first time. Take a sound reading at the same speed you drove before the installation. Note the sound level.

Post the readings as well as what you did to reduce noise in this thread.

Some notes on sound readings
The decibel scale is logarithmic. That means that changes are not linear...for example if you measured 85db before and 75db later, you didn't reduce noise by 12% (the difference 10 divided by the original 85). You actually reduced the sound level by 1/2. A 10db change down is 50% of the original.

So if you reduce the noise by 10db, you have cut it in half. However, that does not mean the sound is half as loud to you. The human ear is not linear either; so reductions in sound level do not necessarily sound quieter to the ear. This is one reason why subjective reports are hard to understand.

If you can help with this, we can compile some objective expectations for various noise reduction solutions.

It's a sports car.

Sports car.....

They made the G37 for this reason.

...? I don't remember agreeing to that.

Like the others say - it's a sports car. If you wanted a quiet, easy ride...Infiniti dealership was probably right next door?

get a new car

Really, how did you come to that conclusion?

I've owned mine for almost a year and a half - it is not noisy.

And, as others have pointed out, it's a sports car...

My ears are still ringing from my ride to work today.

I don't mind the noise

I've actually done some research and discovered that the faster I go, the more noise the car produces - any solutions for this?

*sigh*

What a bunch of idiots on this board.

Every review of the 370Z complains about the noise - what do you think that does to people's opinions considering buying the car?

I owned an MR-2 SC and an NSX - the 370Z noise is worse than both, though not necessarily louder than my HKS Stage II MR-2, just much more annoying.

Mine was 106db with the wife inside, and 85 without her.

Yes it is a sports car. Bad answer, narrow thinking, and acceptance of something that is unnecessary. High cabin noise does not a sports car make, any more than putting a big-*** wing and loud exhaust on an FWD Accura makes it a sports car.
I would enjoy my Z on road trips immensely more if the road noise was reduced and it would take nothing away from the rest of the sports car experience. I don't expect it to have an interior noise level like a high end Mercedes, but I don't think that some effective engineering by Nissan to reduce the noise level of the car would have compromised anything else in the overall performance of the car either.

have you owned a WS6, cause you sound just like someone else on this board.

all this talk about noise is giving the 370 a bad rap to people thinking about buying the car. to those complaining did you even take a test drive and if you did stop crying about the road noise. it is not that bad.

^ This!

I myself noticed no unnecessary noise during my test drive; I was allowed to take it on the freeway as well; the ride is very smooth & I was actually amazed how quiet it was compared to my integra

I think it's part of the raw character of the car. I enjoy hearing the tiny pebbles/sand/water under the tires, I enjoy the limited visibility (in a way), I enjoy that I can hear the clutch when I depress the pedal prior to starting the car. I even smile when I open the hood for cleaning and have to use a prop rod like an old muscle car.

These are some of the reasons I bought the 370Z over something similarly priced but quiet/refined/boring, like a G37 or IS350.

Buy a better stereo, put on some good music and try a smile once in a while that you own a Z.

Drive slower...


To the OP:
I have no issue with any noise, so it's not a general agreement, it's the opinion of a few.... As you stated, it's subjective...

Just out of interest, outside of applying noise absorbing material, what are these several solutions you are referring to?

i think that those buying this car knew full well what they were "getting into" and as such noise is not a problem for us. the reviewers might have a different opinion and thats they're problem, but i'm also perfectly happy with my car.

those who didnt like the loud noise pretty much just dynamatted it.

From Edmund's InsideLine

Nismo 370Z Test Results:

Test Results:
0 - 30 (sec): 2.1
0 - 45 (sec): 3.6
0 - 60 (sec): 5.3
0 - 75 (sec): 7.7
1/4 Mile (sec @ mph): 13.6 @ 103.2
0-60 with 1-ft Rollout (sec): 5.1
30 - 0 (ft): 28
60 - 0 (ft): 115
Slalom (mph): 70.4
Skid Pad Lateral acceleration (g): 0.91
Db @ Idle: 47.1
Db @ Full Throttle: 84.8
Db @ 70 mph Cruise: 72.9

370Z Touring Test Results:

0 - 30 (sec): 2.0
0 - 45 (sec): 3.5
0 - 60 (sec): 5.2
0 - 75 (sec): 7.6
1/4 Mile (sec @ mph): 13.5 @ 103.7
0-60 with 1-ft Rollout (sec): 4.9
30 - 0 (ft): 26
60 - 0 (ft): 108
Slalom (mph): 72.0
Skid Pad Lateral acceleration (g): 0.94
Db @ Idle: 49.2
Db @ Full Throttle: 82.7
Db @ 70 mph Cruise: 70.3


Compared to

Mercedes C350 Test Results:

Test Results:
0 - 45 (sec): 4.0
0 - 60 (sec): 6.2
0 - 75 (sec): 9.0
1/4 Mile (sec @ mph): 14.5 @ 96.5
30 - 0 (ft): 30
60 - 0 (ft): 118
Slalom (mph): 67.6
Skid Pad Lateral acceleration (g): 0.83
Db @ Idle: 43.3
Db @ Full Throttle: 75.8
Db @ 70 mph Cruise: 65.2

I have no idea why the Z is getting this bad rap -- seriously. I read what people say on the forum about the noise. I also read reviews that state the same complaint and I still don't get it. I never thought this Z was noisy (or at least noisy in a negative way) until I started reading all this stuff.

Now I am often distracted when I drive because I am trying to figure out if the car is "noisy" or not. Geez, like I need something else to f**king obsess about. Honestly, my obsessions list is long. Everyone who rides with me agree that the car is not very noisy inside. People form my wife to colleagues who happpen to tag along with me all agree that the ride is smooth. These people drive "normal" cars, too.

Sure, under hard acceleration it gets somewhat loud (intake and exhaust help that), but it is the good loud. It is the sweet song sung by a fairly high performing engine that is allowed to breathe correctly. But when cruising it is not at all uncomfortable. I have 13,500 miles so far which include 4 road trips of 800 miles each (driven at 80 – 85 mph).

Is it a fluke? Am I going deaf? Are people expecting too much? I have no clue. I do know though that the Z is, like others have said, a sports car. So go ahead and muck it up with your insulation and decible meters and such. Whatever people do to make them happy in their rides, as long as they are not hurting others, is OK, I guess.

You should have bought a Mercedes C350!

My brothers 350z is def much more quite inside.

It doesn't bother me at all but it's def not as loud inside while cruising or running over rocks.

The noise doesnt really bother me but I'm just stating a fact. I have no intentions of sound dampening material being installed but what the OP said makes sense.

He seems concerned so I think he should conduct his study and post his results.

My .02

wow, i'm actually pretty surprised at the response the OP is getting with this post. i'm pretty sure he was only trying to be helpful.

do i think the z is too noisy, or does the cabin noise bother me? no. is it much louder in the z's cabin than other cars that perform better than the z? yes. do i care? no. do some people care, and would they benefit from the OP's post? yes.

every car has strengths and faults; we all chose to accept the good with the bad when we bought the 370z. with that said, we're all here to improve our driving experiences as much as possible -> to me, that's what the tuner/enthusiast crowd is all about. for me, it's the clutch/transmission that can use work for our cars, and not the cabin noise. for other people, it's oil temps. for other people, it's the terrible base stereo or the bose system. fine, we all have gripes and we want to improve aspects of our driving experience. we still think the z is great.

so this guy has an issue with cabin noise. maybe he spoke too soon when he decided everyone else has the same issue, but he's only trying to crowd-source some helpful data and organize a thread to help other people collect data. then people s**t on him for that with snarky comments; it's disappointing to see that here.

save the sarcasm for retards who ask a question they can answer with the search button, yeah?

OP, go spend some time in the audio/video section and ask the same questions there... a lot of guys should have experience with this question and probably can give you some worthwhile feedback...

Whenever the subject of cabin noise comes up the smart remarks are sure to follow. Some folks just can't resist putting people down if they have views that differ from their own.

I covered the rear interior with Dynamat Xtreme.
Good results. It does a lot to rid the cabin of annoying road noise so that you're hearing more of just the engine sound.

If you don't like the road noise, buy an exhaust, an intake and some high flow cats. Wont here the road noise over that...

Because some views are just wrong to others :p
Some Z members may consider that threads like these bring upon a negative image towards the car, including myself. For me thats a valid reason to state my objection to said views. Besides there is already a thread for this on the same page.

Wow. I didn't expect these type of responses after reading the OP.

I'm pretty sure he was only suggesting this so people can find the best solution IF the noise bothers them. It's like putting your car on the dyno to test an exhaust. If someone finds a cheap solution that makes the obvious sports car noise level go down, would you guys really complain?

Anyway, OP, I suggest a standard place in the cabin to place the Iphone or device. The noise will vary from position to position.

Ill do this test if someone would like to buy me some dynomat.

on the real tho, even with an exhaust this car is just loud. my brothers 350z with test pipes and exhaust is much more quite inside.. when I take him in my car he always says how loud it is.. I am completely used to it but he isn't.. If I cruise at 50-75 mph even with the 4.08s its relatively silent still, but while accelerating and going speeds over 80, it gets a bit louder than I would like. But I am doing nothing to help it with test pipes, gears, and an exhaust system.

A buddy of mine has a 370z with a greddy exhaust, canister style with tit. tips and his car is OBNOXIOUSLY LOUD with test pipes. He comes in my car and tells me how quite it is..

It is what it is, i don't mind it at all... BUT some do, and all OP did was list how to test it... I thought he was going to have results to follow though. I like his concept he needs to try it out and post his results.. So get to it Mr. OP and report back.

Guys, there's no need to personally attack OP for this thread or question. Everyone has their own opinion. Please be respectful to your forum colleague.

As for noise, I don't have any complain because I like my car noisy/raw. I have an HKS exhaust and love it to death. It's a sports car so I don't mind it. If I wanted quieter, I would've been driving a g37. If anyone ever been in lambo or ferrari, you know how noisy they can be. There are plenty of quiet sport coupes that out there (335i, 135i, TTS etc) but 370Z is a little on the noisy side compare to those.

:iagree:
What badass car isn't noisy and raw?!:stirthepot:

Gtr

finally some common sense reasoning.............

Point well made. Just the other day i had a friend who has driven nothing
but high end luxury cars ride with me and his first comment was "hey this rides and sounds a lot better than i thought it would".

:icon18:

FWIW I used some Second Skin Damplifier and Luxury Liner on the hatch after I installed my FI exhaust. It cut down on a little bit of noise (and by little bit I mean little-to-none... like a "trace" of snow accumulation), but since the car is a hatch you really need to do the entire thing if you want to make a noticable impact on road noise. This means pulling the seats, carpeting, door panels, etc. and covering everything. Not just with a Dynamat-type product but with an actual sound absorpotion product like Luxury Liner.

The problem is you could easily go through 200 lbs of deadening to do the entire car.

In my view you don't need a spl meter to do this and, remeber that mobile phone mics are caliberated to work for voice. The op just sounds like a a dorky iphone user. :icon17:

I'm on the "like it loud" side.

IMO - Sports cars should sound aggressive on the inside and out.