Bracing roof to reduce flex

[Vogey84]

I want to reduce the amount of flex in my navigators roof. Atm it flexes to the point you'd think it was hyperventilating. I'd like to keep the factory head liner if possible. I've got a couple ideas. home depot has 8th inch thick flat steel 2" wide 48" long grab some of them and use panel adhesive to glue em a few inches apart side to side then put deadener between the strips. Then use pl3x to stick layers of 1/4" (what Ever it takes to be flush with factory brace) plywood over top between factory braces. Fill in gaps with kitty hair. If there's room a 4x8 sheet over everything. A layer of ccf between headliner and roof. If I can't get headliner to fit go 3/4" sheet over everything put 3/4" sheet over the rear side windows (braced with strips of 3/4 on glass side) , and seal off the very back from the roof to top of the box. pretty much turning it into a 6th order though. Unleashing an entirely new set of problems

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[Vogey84]

Edit I'm running 4 hd3000s on 4 15s atm 16.5ft3 252in2 of port 27" long subs up poet up all the way to rear lil over 14" from roof to top of subs

 

[Buck 5,000+ posts]

Can you fit .5" sheet wood on the top? There are SPL tiles or similar that actually make the surface stiffer, rather than just adding mass with deadener. I personally had .5" wood on half of my roof, and it really made a difference. I was only running 2 18's on 2400 rated watts, but I was playing fairly low notes.

Maybe a warning: the more you stiffen parts of your vehicle, the more pressure it's going to put on other parts of the vehicle. I would be careful with over-stiffening the roof, unless you've really worked on the doors and hatch. IMO, you'd want the roof to flex a little bit more than the doors and hatch, because things that open are going to be worse to fix when they break. I've seen chunks of B-pillar metal, right near the door latch, literally break apart and fall out. My 2 18's broke my half-glass rear hatch mechanism so badly that it ripped the sheet metal and fell down into the lower half. My rear window was hanging on by a single .25" bolt (Ford hatches lol). So, that's just something to think about.

 

[Buck 5,000+ posts]

You could fiberglass the roof, as well. The metal is going to make your vehicle top heavy maybe more than something lighter. I also used Loctite PL to adhere my stuff to the roof. It'll adhere anything to anything, I swear. Never fell off. I had like 50-60 tubes of PL in my Exploder roof alone

 

[Popwarhomie 5,000+ posts]

I would use wood and PL3x. I had 5 layers of deadener on my roof and still not enough mass. You aren't planning on competing are you?

 

[Vogey84]

No I don't plan on competing at all, just having fun, seeing what I can do pretty much. I was only planning on laying deadner down between the strips and 1 layar over the top vb4 inghThe steel strips im talking about ain't all that heavy actually. If I put 20 of them. Up I doubt they'd add up to.much more then 60-70lbs. I actually plan on doin some Fiberglass work, I shouldn't have to worry about the rear hatch, or side vent windows if I seal them off. Now that I've got 8 camera's and a 14" head unit I don't need to see out the back. I'm pretty sure once the roof is braced the weak spot will be the sunroof. I think it would be a challenge to overstiffen the roof while keeping the headliner. I have looked into vibrafkex but the idea of torching it to "burn it in" with the electronics up gjrtehh