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DEI NA/NB insulation kit

DEI NA/NB insulation kit

Regular price $169.00 USD
Regular price Sale price $169.00 USD
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Miatas are great, but they're not exactly quiet cars. This kit won't turn your Miata into a quiet Rolls, but it's a good step in the right direction. This kit, from DEI, uses their Under Carpet Lite insulation, which is a 1/2" thick multi-layer composite material specifically designed to absorb sound and insulate against heat. They take that fancy material and CNC-cut it to custom-fit the NA and NB Miatas. Small variations in the years (e.g., ECU location) are accounted for by scored lines that are easy to cut if you need to remove material but strong enough to hold everything together if you don't. 

This kit is intended for LHD (left hand drive) cars, although it should work on RHD cars if you're willing to trim the insulation as needed to make it fit. Please note that it's not pre-scored to address this. 

Covers the floors, transmission tunnel (except under the dash), rear bulkhead, and rear package shelf. Easy install - remove the seats, pull up the carpet, slip this into place, then put it all back - no dash removal required. 7.25 lbs total, so a trivial weight increase. Be sure to add the Boom Mat sound damping kit for the best in sound deadening. 

How much quieter is it? That's a surprisingly tough thing to quantify. While the decibels do decrease, it's not by much - the biggest difference is that the harshness and tone of the noise is much decreased / improved. That's a tough thing to quantify, but it does make a big difference to how pleasant the car is.




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Customer Reviews

Based on 12 reviews
Al S.

Just installed the insulation kit, it made a nice reduction overall in noise and heat transfer to the interior. Didn’t stop the heat completely, but reduced it by about 60%. It was very straightforward to install, and with a little work and an interior trim removal tool, I was able to work the insulation all the way up the sides of the tunnel; well worth the effort. Very glad I did this kit!

Patrick B.
Makes long-distance highway driving much more bearable

Did this with the DEI chassis + door sound damping kits. It's so worth it if you drive the car on highways for any significant distance. Leaving aside exactly how much noise it cuts, I feel a lot less fatigued at the end of those 300-mile stretches.

It is a bit difficult to reinstall the interior with this, since the extra material puts a lot of strain on 20-year-old trim pieces and especially trim pins. It is doable, though.

Totally worth it.

Great upgrade for the car!

Pretty easy, just tedious install. I combined this with the boom mat kits for the door and chassis and my car is much more of a pleasant place to be, even on the highway, where I spend a lot of time.

I'd set aside 4-4.5 hours or so to do this, being generous. I blew through installing this and the boom mat kit, as well as the isopropyl alcohol cleaning and vacuuming in around 3-3.5 hours. If I took a bit more time, I could've added more of the tape (or even my separately purchased amazon branded sheets which are thicker, maybe wish I did) to the tunnel. I think there's definitely enough space for some more material there, but oh well. I used those amazon ones in the trunk which is another spot for sounds to come through.

One thing I will mention though, is that the carpet behind the seats that lays vertical will only clip in with the top clips, the bottom 4 wont go back in because there's no holes in the DEI insulation for some reason. No big deal, only need the top 4 to go back in, but now I have extra clips. Also, the seats may be a bit annoying to reinstall at the end, because the extra stuffing in the tunnel makes it hard to slide the seats back and forth without them becoming misaligned when you are bolting them down.

I'd definitely recommend it overall. If you're not a straight up race car then this is so worth it.

Great kit

Installation wasn't too hard and the fit was perfect. There were a few carpet clips that were missing holes, but they didn't really affect the install so I just left them off. The material was easy to cut and fit to my roll bar - I used my already cut carpet as a template for where to trim the insulation. The transmission tunnel bits were pretty easy to install, after a few drives the material there settled(the carpet was a bit puffy by the gas pedal). I paired this with the sound dampening kit for the chassis and the doors. Road noise is definitely reduced, I'm glad I can talk to my passengers now without having to yell over the noise. Even with stiffer motor mounts and polyurethane differential mounts, I still find the wind noise made by the hardtop to overtake the road noise. I was surprised to hear a whistle coming from the bottom of my window where my hardtop seals! Looks like I've got my next project cut out for me. I would recommend this for hardtop users, as I don't notice a big sound difference when I'm driving with the soft top on.

Steve W.
No Hassle Install

Having watched the video, the install went easily (especially as my son did most of the work!). My car is a '97 and it is easy to pull the carpet out completely.

That made it easy to install the insulation pad up the sides of the tunnel. My son proclaimed it was worth the work because he was not burning his leg on the tunnel when driving it. He wears shorts much of the time. On these 100 deg days, that may make the AC do its job better. The ceramic tint added previously helps for sure.

I think the sound reduction is pretty much as described in the video. It is not substantial but it sounds different and is easier to tolerate. On the rougher surfaced highway, it always sounded like the road noise was coming into the interior thru the rear wheel wheels for the most part. Now, to me, it sounds more like wind noise on the hard top. I am old and deaf and I find the tone easier to tolerate.

All in all, I am quite happy with the results. I was not expecting a major change but I am very happy with the outcome. I did not mention that I also included the Mass Loaded sound deadener in the install. I suspect that changed the frequency of the noise coming in.