So, after the installation of all my performance upgrades last spring and summer the car had a significant increase in NVH. This wasn't a surprise or a disappointment as I was very happy with the increased power.

However, as a Maxima one of the defining characteristics of the car is that it is quiet, comfortable and relatively soft. Ideally, I would retain as much of that as possible.

I began researching different sound deadening materials such as dynamat or similar products. The first obvious compromise is weight. I'd need nearly 200lbs of the stuff in order too achieve what I wanted and even though it was well distributed adding that much weight would see a significant loss in performance. Counter productive at this point.

Then I found this:

http://quietcoat.stores.yahoo.net/index.html 7

The entire 5 gallon jug weighs 72lbs, I planned on using 3 gallons total, given a cured weight of a maximum of 40lbs. (Likely closer too 30) You
can read up on it on that link or search further through your chosen search engine, but after hearing good things from a few others on the interwebs I went for it:



I stripped the floor and trunk of the interior:





Then cleaned all the too be painted surfaces with a degreaser.

Not having a big enough compressor or the required gun on hand I decided too simply apply it with a brush. There were quite a few carpet clip holes and screw holes for various trims that needed too be taped off, I took pictures before just so I would remember where everything was.

Coating was very simple. This stuff is THICK but applied well, taking about an hour and a half for each coat. I let dry for 8 hours between coats in a heated shop with fans too keep the air moving.





It is a rubberized coating, so if it looks like I coated screw heads (like on the gas tank) they are easily peeled off before reassembly.

Another good thing I hadn't counted on was being able too clean all
the interior parts thoroughly as I pieced the car back together. A nice little bonus.



The Results:

After curing for 7 days I noticed a drop of 10db (as measured by a cheap DB meter available at my local electronics store) on startup...This is significant. Part throttle and highway cruising volume has dropped a LOT.
Road noise such as wind and pebbles have also been significantly decreased

The Verdict:

Worth it.

If I were too do it again I would apply thicker coats. More is better in this case and I was leery about applying too much and it not drying properly. This was unwarranted.

Hence the "Stage 1" in the title. I plan to revisit this at a later date. Going more in depth...Another couple of coats too the trunk area. The underside of the hood. The roof, etc etc.

All in all, this keeps the car more civil and that is never a bad thing.

 

Nice!!! I never even heard of this stuff before. Will definitely look into this for my audio install....

 

Yeah if I keep my car I may do this as well along with improving the weather stripping in the door jams. With this 3" exhaust it can be to much....

 

This is something I've always wanted to pursue. Keeping things as civil as possible.

It looks like a whole helluvalotta work though.

I want to ban you because I miss the black interior of my 4th gen and hate the frost interior of my 5.5.

Great Job, BTW.

 

Nice you got it done! I can't believe the difference, that's incredible. Great work, very dedicated you are

 

I can't wait to hear this next month. Or *not* hear it, as the case may be.

I think this approach to sound deadening is a first for the 5th gen forum. Great detail, and excellent pictures.

You are driving the King of the Hill in 5th gens, Markus. A loaded, tuned and fully bolt-on TE 6MT in Polished Ti. It just doesn't get any better than that. Hat's off to you, buddy.

That car is a keeper.

 

This is similar to what second skin audio sells as spectrum sludge only this is $10 cheaper.

I used a gallon of this in my wheel wells with gr8 results.

For the interior I found Mass Loaded Vinyl to have the best sound blocking (also called luxury liner on second skins website).

I am all done with my sound deadening and now need a double insulated windshield(front and back) and dual pane windows in the doors with better seals to really see more results :P

I'm presently at 68db doing 70mph on a newer tar road(higher on concrete) using the JL Audio db meter on my iphone 4 at driver position.

 

Nice job, I'm going to have to look into this.

 

Wow, 10db drop is huge! Definitely interested in this as well. Problem is getting enough time to take the interior apart and leave it apart long enough to apply all the coats.

 

I went the cheap way of sound deading i lined the entire inside of the car with egg cartons behind every panel and in the trunk...... quite as it can be on the cheap

 

Very glad you created this writeup and that I found it. I've been wanting to do add some sound deadening in my car for quite some time as my GXE feels quite lacking for a quality sedan as far as sound proofing. I didn't want to add a bunch of weight to my car either so this looks like a very viable solution.

 

Thanks for all the kind words fellas. I am quite glad I pursued this, you can't really go wrong as far as making something a little nicer to be in.

The being said, this exhaust is loud (In my opinion) and there is no real way around that other than changing some part of it...I'm not really interested in doing so.

The volume of the exhaust has of course not changed, the intrusion of that volume has. So, the results aren't as mind blowing as I had hoped for.
It will never be a "Quiet" Car set up as is.

 

Love this thread. Look forward to doing this sometime. This is the first time I've seen someone use a spray deadener vs mass loaded vinyl or some other solid deadener.

Looks like a ton of work, love your dedication.

 

Subscribed

 

I may be wrong, as I didn't see you address the doors in the pics or write up.... But, I imagine stage two would include the inside of the door panels. I imagine there's still a good amount of noise coming through there.

 

Yep, There are a lot of areas I left untouched. This was my first experience with the product so I wanted too see the results before I went full on coating everything.

Now that I know it works I'll be doing more down the road, just depends on time, ambition...Etc.

 

Love this thread. Will be looking to doing this sometime in the future. More of an issue finding a garage and time to leave the car for a week to cure. But solid research, pictures and overall effectiveness in this. Cheers to a properly modded 5.5 6MT.

 

Well done! Looks good. Props for taking your entire car apart to do this.

 

That is likely the biggest hurdle for most people, the down time.

However, its not quite as daunting once you tackle it. I had the interior out in about 3 hours (I'm no mechanic) and prepped in another 1 or 2.

So, if you strip and do the first coat on a Friday night. Let it dry that night. Second coat Saturday morning, Let dry that day. Third coat Saturday night. Reassemble on Sunday. It CAN be done on a weekend.

The cure time is 7 days for full sound deadening qualities too take effect. Dry time is as little as 4 hours (Per Coat)

 

Nice job. So far I have 2 dynomat trunk kits in my trunk and inner and outer shell of my front doors. I need to hit up the rear doors and then I will move on to something like you are doing. I wonder how this stuff will work on the roof? Is it prone to cracking? Cuz my roof waves with the bass. This is due to my current personal best of 138.8 db from my sound system.

 

Wow, that is freakin loud.

Prone too cracking? I don't really know, it is a rubberized visco-elastic polymer...That doesn't sound like its going too crack too me....

I'm curious about doing the rest of the car with it too, The roof should work just as well as the rest of the areas I would imagine. For an extra measure I'd probably do the back side of the roof liner too.

 

I would have just dealt with the noise lol...that seemed like a heluva lot ova work-a. but still nice job

 

Damn good work...wishing I had the patience for all of that....taking out all of the stuff im sure it is no big taking it out but putting it back in I know it would be a B1tch...Nice Job though....

 

So what is its consistency? gel-like? rubber-like? or is it solid?

 

another good product is lizard skin, looking to do the same with mine soon.

 

Pouring it out of the 5 gallon pail into a 1 gallon pail the closest similarity I can think of is carpenters glue. Its thick and piles up on itself as its being poured.

Once hardened it has a smooth matte finish that is hard but not brittle.

 

Very good thread I might be dong it real soon as well....I think this is lighter and less expensive than applying a mat type sound deadening material......I'll be ready for that %.5th Gen downtime once the 3rd gen is up and running!!!!!

 

I've always wondered about the odor from products such as this. How is the odor of the stuff? Does it leave any odors after it dries? I'd hate to have my car smell like a paint shop/flammable fumes after the stuff dries...

 

Just out of curiosity… y’all read Metal’s thread?

The Definitive Sound-Deadening Thread!!!

 

I was thinking about this thread today after I test-drove a friend's brand new Buick Lacrosss, which was as quiet as a coffin. Although decidedly unlike the OP's car, the Buick also performed like a coffin. (yawn)

OT, I know. Carry on.

 

Obviously I can't speak about other liquid products but QuietCar is an ultra low VOC water based compound that had very little odor. Even when being applied it wasn't half as bad as some paints I can think of (KILZ)

Once dried and cured its not noticeable at all.

Buick Lacross eh? Was it the new Turbo version John?

 

No. It was a 2011 CXS, (at over 2 ton, btw) with the 3.6L V6 @280 hp.

It was a complete slug compared to my Maxima.

 

I'm glad too hear that. I wasn't sure of the weight but I always like knowing that my old car still has an edge over the new higher powered metal.