djejglk

About to dynamat the spare tire area, but through all the pictures I've looked through, I haven't seen this..



There is a device wired to the plastic tray where the spare tire sits, and there is also some sort of slotted holder looking thing on the right. It looks like it may be used to secure or hold something, theres also two holes for screws on this thing. Nothing is there of course, nor do I see anything ever being there, I just didn't want to cover it up without knowing what the heck it's for.

Any ideas what these 2 things are??

Sportstick

Try starting the car while the spare is out and see if you get a low pressure warning. Just wondering if they added a way to read a TPMS from the spare to protect you from the spare being underinflated when you need it? In any event, I would think you could work around/under/next to the wire harness path and still get close to 100% of the benefit. As to the holder, not sure, sorry, but likely a feature for some other market. They like to make dies and stamp parts the same worldwide, if possible. I see no reason not to cover it, if it was unused for your car.

If you found my thread from a couple of years ago, it said what a great difference this mod makes for NVH.

djejglk

That's a great idea, thanks for the info. I'll work around it, and will let you know about the no-spare test!

djejglk

Took the spare out, started the car...no warnings/flags from the car. Interesting little wired box we got there.

J__

unplug it and see what happens

Sportstick

Just before dismissing this possibility, take it for a drive with the tire out too. It may take a few minutes for the lack of sensor to register, if this theory is correct.

C300CA

My salesman said the slotted area next to spare tire was for the battery, which is now moved to the front.

djejglk

Good deal. COVERING IT!!!! lol

I'll take it for a drive to test my work (without the tire) and see if anything trips as far as the sensor goes.

djejglk

BTW Sportstick, I had to google NVH (noise, vibration, harshness) to see what it meant

C300CA

Hi djejglk, How will you judge the dynamat result, by just listening it or using a dB meter?
I am very interested in noise reduction but if it is "maybe better", then I am not sure I want to do it.

Sportstick

Sorry about the abbreviations....24 years inside one of the domestic auto manufacturers will affect the vocabulary! Here are a couple of others to keep handy which might come up on a forum...

TGW=things gone wrong
TGR=things gone right
BSR=buzz, squeaks, rattles
CWI=cost,weight, investment (a key factor of deciding content!)
TCF=trim, chassis, final (the assembly line portion after the body is formed and painted)

and not an abbreviation, but this one drives me just a little crazy....

tires have "tread"
fabric and email chains have "threads"


It's not a "maybe".....a definite improvement if you do a thorough job.

https://mbworld.org/forums/c-class-w...d-you-use.html

See post #14-29 and beyond....

djejglk

I'm actually an audio engineer, and a little OCD. I'm in the process of doing the job now. I didn't do a before measurement, but if there's the slightest difference, trust me, I will hear it. Will report back soon...

djejglk

Making progress...

C300CA

Great, I am waiting for your final report. Are you doing as many places as you can get easy access to, or just the trunk area?

If you can definitely tell the difference then I will definitely do it the way you did.

Acapulco Bill

OP djejglk: You are an audio engineer? Too bad you just didnt go for your daily drive with a sound level meter or your smartphone and an SPL program and actually measure the dB. Then add Dynamat in stages. Then you can say "Lining the spare area gives 2 dB less on rough roads" etc for all of us.

Areas IMHO that are noisy: Besides the entire trunk and under the parcel shelf, on the left and right sides of the rear seat in front of the rear wheel wells; lower part of rear doors; rear floor, in that order. Maybe some noise from lower front doors.

If you have the stock OEM Audio20 unit when you line the doors, you can replace the horrible $1 for all 8 speakers with something 3 to 6 dB more efficient - flat - and extended range like the Infinity Kappas. Link here:
https://mbworld.org/forums/c-class-w...r-upgrade.html

I have a roll of Fatmat laying around, maybe a sound test is in order, first determining levels on a specific stretch of rough pavement in my dead quiet FORD, then the W204, then various stages of dampening. A good weekend project. I have a couple of SPL meters but are only good to 0.5 dB and no graphing capability. Would prefer to have a spectrum analyzer, maybe a decent mic and a MacBook? We will see...

djejglk

Sorry, when I said audio engineer, I mean I record and mix TV commercials. I don't have a lot of technical measurement equipment or anything like that. I was just saying that I care a lot about the way things sound, and appreciate quiet environments, like our VO both and such.

The dynamat in the trunk only, to me, is not a night and day difference. It feels more "solid", but it's not the end all be all solution to a perfectly quiet car. I'm glad that I did it, but I'm not going to go any further, as the car wasn't horrible sounding to begin with. I was just looking to help it out a bit, and this 'mod' did take it a step in that direction.

Sportstick

I had a more enthusiastic response than you seem to be experiencing. I don't know if it relates to personal perceptual differences, or that you used dynamat and I used Damplifier Pro. But, I also did find that extra sense of "solidity". Either way, it is certainly a step in the right direction.

Acapulco Bill

Sounds like a project I will just have to make a commitment too, having repeated in many posts that (quiet) is one of the reasons I bought a Ford 3 weeks after the Benz and use the Ford as my always-puts-a-smile-om-my-face daily driver because the Merc is just TOO DAMN NOISY. Promise to Post with real-time SPL charts and true dB noise reduction per area application.

If the Merc were as (quiet) as the Ford, I would drive the Merc a lot more. Now if I can only fix that lazy lethargic snail-like 7G Tronic and the terribly bbbuUummMmmppPppy Sports suspension.... Oh yes, the novocaine numb steering?

C300CA

C-Class too noisy? Before I decided on my 2001 C300, I checked Consumer Report on quite a few similar cars such as BMW 3-Series, Lexus, Volvo, Audi, etc. C-Class is the quietest, rated 8 of 10, BMW 3-Series is 3 of 10 if I remember right.

I like car to be very quiet no matter it's sports/sporty or not. I will put sound deadening material in the trunk area since it's the easiest accessible area.

edgalang

I agree with C300CA. My 2012 C350 is the quietest car I've owned so far. I also purchased a Lexus hybrid 6 months after for my wife and the C350 STILL offers a quieter ride then that. Either Acapulco Bill has a lemon of a C-Class, or he has a very special Ford, or both.

Not knocking on Ford, since I owned one in the past (technically a Mercury Sable) but I was definitely not impressed (although it was still better than a Taurus my family owned prior). I do know Ford quality has improved greatly over the years, but my wife still can't get past the stigma of American made cars (hence the Lexus hybrid instead of the Ford C-Max, even though I kept pushing for the C-Max).

Acapulco Bill

Coincidently, I obtained Sunday both a SPL meter AND a 1/3 octave spectrum analyzer. Doesn't do Fast Fourier Transformations (FFT) though. Darn! The first thing of course that I did was to check how flat and extended the Infinity Kappa installation is. Actually it is very, very flat, without peaks or valleys, as I had already spent some time with the parametric equalizer in Engineering Mode, but I need to get a 100% accurate white noise source, the MB radio has all kinds of muting that defeats using AM as a white noise source.

I will take the time to do a dozen runs in both the Benz and the Ford. Although I did run the C300 just yesterday on the specific stretch of highway I will use for the noise test, and WOW is the Mercedes LOUD. Perhaps a lot has to do with the tires, which OEM are Michelin Primacy HP's, not the quietest thing around. But the Belgian built Porsche-engined Ford (never sold in the US but in England, Belgium and Luxembourg the most popular sedan) which was Top Gear's Car of the Year twice, is very nice. My 4 Bimmer-owning children steal the Ford whenever they visit. One daughter in San Diego just bought a Ford and her husband steals that instead of using his 328i (one with the 3.0L not the newer 2.0L twin turbo). We even just drove to Las Vegas in the Ford, quieter and more confortable, with much more room, than the 328i. More economical MPG-wise also.

I will try and see a way to do this in the next two weeks. Will post color graphs per vehicle at various speeds, to scientifically see if my opinion is prejudiced or not.