# Truck cab air vents - please, shush-up....



## tulse

There are two vents in the rear of the cab in my truck. They were a secret to me until recently. I have the rear bench seat out at the moment, and that's how I discovered the bastards. Those things are loud! 

Is there a common fix for this - a baffle or such. Or, can I just kill them with some CDL. 

Are they really necessary for ventilation? I don't want to suffocate and turn blue, but anything short of that is fine by me. 

Thanks


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## jcollin76

This will give you some of the pros and cons of sealing them...
http://www.diymobileaudio.com/forum...4460-rear-wall-cabin-vents-truck-seal-no.html


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## BuickGN

What's funny is I recently went back and really sealed up my IB setup as airtight as I could get it. I've also been complaining that I need to replace the cabin air filter because output is pretty bad. It didn't occur to me that it might have been from sealing the trunk off (which is where the vents are)from the cabin. I need to try it with a window down to see if it's the lack of vents that's causing it.


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## jcollin76

When I had mine sealed up, output easily doubled on my AC when I cracked a window/ door. 
The cab got so pressurized, you could hear the air being forced out of the seals.(from outside the truck) Lol yeah, had to fix that.


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## tulse

jcollin76 said:


> This will give you some of the pros and cons of sealing them...
> http://www.diymobileaudio.com/forum...4460-rear-wall-cabin-vents-truck-seal-no.html


Thanks, I'm really thinking about throwing together some simple baffles then. 

What did you end up with? Any tips on a design?



BuickGN said:


> What's funny is I recently went back and really sealed up my IB setup as airtight as I could get it. I've also been complaining that I need to replace the cabin air filter because output is pretty bad. It didn't occur to me that it might have been from sealing the trunk off (which is where the vents are)from the cabin. I need to try it with a window down to see if it's the lack of vents that's causing it.


The vents are bloody 7"X3"-ish. No wonder why there's so much noise in cabs. I just replaced my obnoxious muffler with a dynoflow turbo, too. It's MUCH nicer, but those vents have to be tamed.


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## jcollin76

Honestly, haven't gotten to it yet. Plan was to address it when I pull the rear seat again. Haven't gotten that far... 

Passenger vent is covered to help with exhaust noise. Driver side is open, and ill be messing with it in the future. 

Noise is not as bad as open, and the pressure situation isn't as bad... but could be better.


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## BuickGN

tulse said:


> Thanks, I'm really thinking about throwing together some simple baffles then.
> 
> What did you end up with? Any tips on a design?
> 
> 
> 
> The vents are bloody 7"X3"-ish. No wonder why there's so much noise in cabs. I just replaced my obnoxious muffler with a dynoflow turbo, too. It's MUCH nicer, but those vents have to be tamed.


I had a few paragraphs written but then I realized I forgot to ask the most basic question. These vents contain flappers that only let air travel out but not into the cab, right? Is the problem with outside noise getting in through the vents or is it the flappers making noise when the bass hits?


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## tulse

BuickGN said:


> I had a few paragraphs written but then I realized I forgot to ask the most basic question. These vents contain flappers that only let air travel out but not into the cab, right? Is the problem with outside noise getting in through the vents or is it the flappers making noise when the bass hits?


It's outside noise that's the problem. The vents do look like they have flappy, one-way louvers, though. The vents are behind the trim. I'll pull it off and get a better look tomorrow.


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## BuickGN

I wish I could help but I've never had a car with vents in the cabin. You can always cover them up temporarily and see if it makes a difference. I can't imagine it making a huge difference though, they're normally closed unless the HVAC is being used. I'm interested to hear your results though.


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## tulse

No problem. I appreciate it. Should be prety easy to do some trial and error stuff.


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## mojozoom

I heard that these vents were also there to vent pressure during airbag deployment.


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## pjc

I guess u need to look into it further too. But I completely covered mine when I Raammatted my truck. I actually just went right over them with a piece of raammat. I've noticed a quieter ride. And never noticed any extra noise with the AC on. And no airbag deployment yet so I can't vouch for that part.


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## BuickGN

I'm sure they help with airbag deployment. However, my airbagless GN has roughly the same vent area as the TL. That probably means nothing though. For all I know it might mean the difference in blown eardrums. Hopefully my IB15s would have a little give in the event of airbag deployment but I'm sure they can't come close to covering the amount of volume the airbags displace.

I did try rolling the windows up and down with the fan on high today and there was no difference. I guess it really is just time to change the cabin filter.


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## MUGWUMP

This should take care of that shouldn't it? 

http://www.diymobileaudio.com/forum...equested-pictorial-big-meat-rear-sub-box.html


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## Aaron'z 2.5RS/WRX

The vents are there to equalize pressure, when you close a door, when you turn on the fan....ect.... 

Rip the flappy out or seal over it... you've got one of 2 choices..

Rip it out, run the risk of water/dust, cover it and pressurize the cabin constantly, I've done both...


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## tulse

I'm going with option somewhere-in-the-middle. 

Passenger side vent is getting covered. It's right over the muffler, basically. For the driver's side, I'll make a simple foam lined, right angle baffle. How does that sound? That should get rid of that high frequency wind sound, I'd guess. 

I was actually mistake about the louvers. They do not move (are not hinged).


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## Timelessr1

what kind of truck? I know on mine (2010 F150) the "louvers" only move when you choose to blow aire NOT using the recycle air feature. when you use the recycle air feature, the louvers do not move at all....


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## Aaron'z 2.5RS/WRX

Timelessr1 said:


> what kind of truck? I know on mine (2010 F150) the "louvers" only move when you choose to blow aire NOT using the recycle air feature. when you use the recycle air feature, the louvers do not move at all....


 
Right, because on the "recycle" setting, you are recycling the air, not taking any from outside... .:laugh:


Come on man, think a minute...


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## Timelessr1

Aaron'z 2.5RS/WRX said:


> Right, because on the "recycle" setting, you are recycling the air, not taking any from outside... .:laugh:
> 
> 
> Come on man, think a minute...


haha..i know that....


but the op said his didnt move...and i find it hard to believe that they dont...i have a feeling he tested it and looked while he had it in "recirculate " mode. I know when i had my back apart and had the air setting in normal mode it sounded like a freight train was back there.


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## iregret

If someone figures out a way to quiet those things down, I'd love to hear it.


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## Aaron'z 2.5RS/WRX

Timelessr1 said:


> haha..i know that....
> 
> 
> but the op said his didnt move...and i find it hard to believe that they dont...i have a feeling he tested it and looked while he had it in "recirculate " mode. I know when i had my back apart and had the air setting in normal mode it sounded like a freight train was back there.


Hahahaha troof...lol

Sent from the other side using mind bullets...(YapaTalk)


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## Aaron'z 2.5RS/WRX

iregret said:


> If someone figures out a way to quiet those things down, I'd love to hear it.


The way is here.. remove them or cover them...

Sent from the other side using mind bullets...(YapaTalk)


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## BuickGN

Its off topic but does anyone know the percentage of air that has to be fresh when in recycle? I knew it once but can't remember.


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## Aaron'z 2.5RS/WRX

BuickGN said:


> Its off topic but does anyone know the percentage of air that has to be fresh when in recycle? I knew it once but can't remember.


 I didn't think any came in fresh on recycle, besides what leaks in/out through the "vent of hell".. :laugh:


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## minbari

mojozoom said:


> I heard that these vents were also there to vent pressure during airbag deployment.


highly doubt it. 

They are there so that the heater/air conditioner can pull air into the cabin. good test if you have them sealed up. turn the "recirculate" on and see if volume increases alot.


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## minbari

BuickGN said:


> Its off topic but does anyone know the percentage of air that has to be fresh when in recycle? I knew it once but can't remember.


the manual on my Audi says 20%


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## Cooter69

I would seal one all the way and do the other one half way, that is what I did and worked pretty good.


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