📓 Journals Adding Lightness

[Eagle7]

Just got the Mega Matt and Ill be installing when I get my fabricator to extend the Aerie tips. Hoepfully removes the boominess on the higyway and reduces trunck temps. Mind you the mega matt isnt light. Thanks for all your input.

Make sure you have the high temp foil insulation tape, to tape up the joints and seams.

High Temp Foil Insulation Tape - Large Roll

HVAC tape will seal edges for high heat car sound insulation projects or tape seams to create more effective noise barriers.

www.secondskinaudio.com

If you've ever handled Dynamat or some of the other brands, you'd appreciate how light the Mega Mat actually is.

The resonance boominess is most noticeable at 2,000-2,300 rpm which unfortunately is where the rpm sits in 6th gear at freeway speeds. After these mods, it's only really noticeable if you press the gas pedal when it's in that range. As soon as the rpms get above that range, the resonance stops. At a steady cruising speed, it's not bad. I'm going to keep exploring and see what exactly is resonating at that frequency to see if I can isolate it. Typically when I've dealt with this issue on cars in the past, it was the trunk cavity that was the culprit.

Okay, as I was typing this I realized I hadn't actually done any sound tests on the trunk because the Emira's trunk isn't that big. So I just now went into the garage, and using a rubber mallet, began testing the bottom of the trunk and sure enough, it sounds boomy! especially on the passenger side. I'm going to check in the manual to see if there's any particular trick to removing the carpet on the bottom. I bet some Damplifier mat on the bottom will stop that resonance completely, and that might do the trick!

 

[Eagle7]

Energized by this new discovery lol, I went out to the garage and did some work. Here's a sound test using a rubber mallet and tapping on the left side, middle, then right side of the bottom of the trunk: The passenger side clearly has the worst amount of resonance. (You can hear it best with headphones).

I removed the carpet which is easy (you just lift it out after removing the battery cover, and the two road kits velcroed in the back). There's a large flat piece of plastic on the bottom.

I cut 3 pieces of Damplifer mat and placed them across the bottom. This is the left side to show the size; they're one foot wide.

Here's the sound tap test after installing the Damplifier mat. It's better, but you can still hear a slight amount of resonance on the passenger side which originally was the worst side.

It looks like the plastic bottom of the trunk well is bolted onto something underneath, which has to be metal of some kind since it's above the muffler. I'm going to do a road test to see what effect this has made, but I won't be able to do that until tomorrow since its raining and windy outside right now. It's supposed to be clear and dry tomorrow, so I'll report on the results then.