dynamat over rear vents in truck?

I've removed the rear seat in my ext cab Ford F150 to make room for three subs, and noticed I've got these rear vents that open to the underside of the cab. They are like flaps that spring open with air pressure. I read somewhere (can't find it now) that folks were sealing them up. Can't remember if was to create better sound dampening, or better spl in the truck. If I seal these will my ac/vent/heater work ok? Or is this something, just for people trying to get every little bit for a competition? I'll be running 3 10W3v3s ported with 500/1 and a 250/1.

  If im not mistaken these vents are for releasing pressure when you slam your door shut.  Means nothing when the windows are down but comes in handy when all windows are up.    Hopefully someone who knows more about air velocity and air pressure can elaborate.

I understand now after driving the truck with the seat out. The road noise is very loud. I'll be sealing them up for sure.

ra0062 wrote: I understand now after driving the truck with the seat out. The road noise is very loud. I'll be sealing them up for sure.

I wouldnt. I havent tried it but people that have said their ears popped everytime they closed the door with the windows up...

Just tryin' to learn...

i have a 2004 f150 and noticed the same thing(the increased noise) when driving without my rear seats and carpet.

I sealed mine off, and had to seal all the seatbelt bolts holes to (they whistled). I left my carpet in place, and ended up leaving the the back part of the seat in the truck. What I like is the spl in the cab, kinda hurts my ears unless I roll the windows down. The a/c doesn't blow into the cab like it use to, and my amps do not get that great of air flow, mounted on the step where the seat was. But no over heating problems. Very little bass gets out of the cab with the windows up.

I've worked at a body shop and those venst are needed for air pressure regulation when you close the doors. not only does it take pressure off your ears but also off all the windows which are only held in by urathane. I highly recomend not covering them up.~*Sparky*~

Fords are notorious for this. I also would not recommend sealing them up. Makes it real hard to close the doors.

Depends on the volume of the truck I have a Dodge Dakota Quad cab, I dynamited over mine and do not have an issue with pressure in the cab, I think however is smaller trucks it does make a difference, I do know that in my application I did not see an issue with the rear vents.The basic difference between an ordinary

man and a warrior is that a warrior

takes everything as a challenge, while an

ordinary man takes everything as a

blessing or a curse.

-Don Juan