How'd you measure? In the interior? Closed windows? I have full interior, no ST nor parcel shelf carpet, HT with roof liner and it measures around 60-62dbA at idle, up to 70~ dbA cruising 3-4k rpm, up to 80~ on fwy (4k, 80mph), and only ever reaches close to 90dbA with my music on top of it all.

But then again, opening the window doesn't really increase the db level, and the db reader i'm using probably isn't high-tech, it has a few ranges from 40-70, 60-90, 80-110 etc so I still question it's accuracy.

This is with a Tsudo N1 with silencer, Cali-spec cat.

 

I used the phone app that's pretty accurate compared to the SPL meter at HHR. The windows up, highway cruise at 4000rpm.

 

For a sole DD I'd get a more economical/quieter/safer/more practical Camry or something dirt cheap. Hell, probably anything with a solid roof and weighs a lot more would be much quieter. Just boring to drive.

 

I did the same stuff as 18psi and helped quite a bit. Actual dynamat is very expensive but a lot of people use "Peel and Seal" from the roofing section at Lowes/Home Depot, which is what I used. I think I used around $100 worth of it which pretty well covered the interior and trunk, I still want to do the doors sometime. This is what you're looking for:

 

I will probably always drive a Miata daily. Its little so I can park it anywhere, its very cheap to drive, and I'm full-homo.

 

A 1993 Ford Taurus would fix all your sound problems.

 

How? By being a gigantic, bloated, overweight raging POS? lol

 

Look into doing the wheel wells/backs of the fender liners. Driving to work at 75 last night (around 4000 rpm), I feel as though most of the noise comes from the tires and wind noise around the top and door glass. I don't get many squeaks or rattles until the road gets rough, and most of the squeaking comes from the soft top frame flexing.

If I were to do my car, I would probably apply strips of sound deadener (I like Second Skin's products) in the doors. And for the wheel wells and fender liners, I would probably look into using some sort of acoustic mat. Maybe Second Skin's Luxury Liner.

 

I remember a thread on M.net quite a while back. The consensus was that the tunnels on either side of the back shelf transmit a lot of noise, and act as ports to accentuate certain frequencies. The poster claimed stuffing them with something (I don't remember what material was used) helped quite dramatically.

 

I've used fiberglass wall insulation all over, filling all the crevices in the trunk, an extra layer under the parcel shelf, etc.. It made it quieter, somewhat-- but overall most of the noise that I couldn't deal with were from creaks and rattles. ST delete, HT latch delete solved that problem.

 

I would like to find a way to make the MSM sound "quiet" like a high end sports car. Maybe it's not possible with the miata 1.8?, but that's what I'm after.

 

Trey, please read this thread:
https://www.miataturbo.net/general-miata-chat-9/stripping-miata-hell-48471/

Amazing results.
The entire project added maybe a couple pounds to the car. Maybe less.

But, you have to take your time. It pays off big time.

 

Add a lubed muffler just after a manifold.

 

I can't see what you used (pics blocked at work), but from the comments I'm guessing its the same stuff I posted earlier in this thread.

And Trey I've driven my daily driver (forester) this weekend after doing up the rear section (basically the "trunk") and noticed an improvement already. Though now the noise is coming from *everywhere else*.

So in the miata I am now also going to do the doors. After that I think pretty much every square inch of the interior will be dynomatted.

If that's not enough I have a roll of multi-cell foam I'll also cover the interior with.
And like others said, the stuff isn't heavy at all: 50sq/ft of my stuff weighed just under 13lbs

 

that was a 5x8x18 muffler, not 5x11x22. I acutally dont have any clips of driving around with it IIRC.



FAT MAT on ebay is pretty cheap. I think I got a $40 roll and did my trunk, rear shelf and some of the doors and still have a bunch leftover.

 

Speaking of trunk: if you cover the whole rear shelf and behind the seats, whats the point in covering the trunk? I haven't done the trunk in mine yet, cause I didn't think It mattered since I basically "enclosed" the interior in this stuff.

 

I has a subwoofer...I did mine mainly for bass rattles.

 

CKearns gave me some foam for my tunnel and the results were surprisingly good. More to come later when it cools off.

 

did someone buy that cool mat in the for sale section yet? i bet that would help a lot as well.

 

I considered it, then passed.

You only get a small piece of it vs getting like 100sq/ft of fatmat for the same price