Trunk lid jumping up and down help calm it!

[InFaMoUs119 10+ year member]

so a few months ago i bought new dual 12' kicker solo classics already in a kicker made sealed box package shortly after kicker discontinued the solo classics i picked up the package new for $349 new (thats half price from retail)..so i put them in the trunk and start to have a little rear trunk area rattle.i buy a dynamat xtreme trunk kit and install which calmed it nicely for the kickers i recently sold the kickers for $325 bcs i was never happy with them really, i stepped up to 2 new sundown sa 12's in a ported box built buy JG construction ( a supporting vendor on here). still using the same amp that was powering the kickers..but my trunk lid rattles violently now! the whole trunk lid lifts up so how should i go about calming it? a 2nd layer of xtreme on the trunk lid or should i try a different dynamat product on top of the exisitng xtreme layer that is covering the trunk lid? i see they offer other various products such as dynaliner,dynapad ect. what will work best?.....(btw the kickers i had have NOTHING on this new box and the sa's even tho we are comparing small sealed vs a nicely built custom ported box...these sundowns are violent.

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[InFaMoUs119 10+ year member]

there is a 3' by 10' slot that i did not want to cover with dynamat for getting in to replace the small brake light if needed that i left alone with the kickers but with the sundowns i rolled up 2 washrags and crammed them in there nice n tight even but dosnt seem to calm it much the car is a 2010 cobalt sedan.

 

[goingdef 10+ year member]

dynamat isn't going to stop pressure like that time to reinforce the crap out of it, I turned my box facing into the cab with the back of the box up against the trunk lid and it helps reduce some pressure on the lid, but I'm not worried about the lid moving as much as look at your latch hook it will show signs of wear and my modded one is half way through and it's only 6 months old.

 

[InFaMoUs119 10+ year member]

dosnt firing the subs towards the cabin cause a loss of deep bass notes? im not sure myself just asking. i have to remove the rear seats and basically kick the box in after the halfway mark to get it in the trunk

 

[murph 10+ year member]

Expanding foam will help a little.

 

[BlactimusCrime 10+ year member]

im not sure how the deck lid is made with those, but if there are hollow support cavities in the trunk lid, get spray foam and fill them, it helps a good deal.

 

---------- Post added at 07:02 PM ---------- Previous post was at 07:02 PM ----------

 

Expanding foam will help a little.

dammmm you!!! just a few seconds faster than I was!

 

[kramer_212 10+ year member]

Expanding foam will help a little.

this ^ i think it will help alot, i actually just got done doing the lid on my work car, because it kept coming unlatched, (i have some industrial rubber heavy stuff).

also i bent the pinchwell up, and what i like to do is pull the seal off overlay sound deadning on it, and hammer it back on, creates a hell of a seal and gets rid of all the rattles.

 

[InFaMoUs119 10+ year member]

the lid does have hollowed supports but i have it all covered with 1 layer of extreme already from when i had the kickers it was enough for them but not the sa's...how hard is it to get that **** off? the dynamat) and will i be able to re-use the same peice after i fill the supports? thanks.

 

[goingdef 10+ year member]

let me know when you start finding cracks and rips!

 

[quackhead 10+ year member]

the lid does have hollowed supports but i have it all covered with 1 layer of extreme already from when i had the kickers it was enough for them but not the sa's...how hard is it to get that **** off? the dynamat) and will i be able to re-use the same peice after i fill the supports? thanks.

A can of Spray Glue from Lowes...if you get it off without tearing it in little pieces...might try a heat gun to heat it before pulling , if it acts like it wants to tear?

 

[murph 10+ year member]

Never understood why people with trunk systems that are loud as shit don't get their trunks rhino lined. It would keep the flexing down along with making the trunk not crack.

 

[filtor1 10+ year member]

Fire the subs and port into the cabin and seal it off completely from the trunk. It is the only real way to eliminate trunk rattle. I have done it several times and will never have a rattle trap car again.

 

[goingdef 10+ year member]

Never understood why people with trunk systems that are loud as shit don't get their trunks rhino lined. It would keep the flexing down along with making the trunk not crack.

mainly because I will tear the entire system out if it get wrecked and since quite a few of my cars have went that way I try not to sink money in that I can't directly tear out, hence the no real deadening.

right now the thing I'm trying to fight is the roof of the car and the dome light smack together when the car really stars flexing and it sounds like the subs are bottoming until you press hard in the center of the roof, I'm thinking there expanding foam will help.

 

[Chriszle 10+ year member]

I'm running 5k to 2 9500s in my trunk. Filled all the supports. 3 layers of AT later. Still flexes, but its not so bad. The roof is wayyy worse.

 

[THATpurpleKUSH 5,000+ posts]

Never understood why people with trunk systems that are loud as shit don't get their trunks rhino lined. It would keep the flexing down along with making the trunk not crack.

I would think it would make you loose spl due to the softness of the rubber. You want all surfaces as rigid as possible to reflect the sound waves and not absorb them. A guy at comp back in October told me that he gained 2db just from taking the carpet off his box.