truck blow through

[Subarufool 10+ year member]

does anyone know of any websites to help me with a blow through for a truck?~?

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[dyabolical 10+ year member]

What truck? Model, year, cab...stuff like that.

 

[Subarufool 10+ year member]

1979 gmc truck regular cab

 

[dyabolical 10+ year member]

Interesting choice of truck to use....i personally do not like blowthroughs...at all. But to each his own. Sorry i don't have any info for ya, and goodluck.

 

[Subarufool 10+ year member]

well i was planning on stuffing 2 rl-ps in there and in dont think theres enough room?

 

[dyabolical 10+ year member]

Have you taken a measuring tape and taken some rough measurements? This can give you a rough idea on your max mounting depth, width, so on and so forth.

 

[thejoker989 10+ year member]

I searched but am still wondering what a blow through is???

NVM, google....

 

[dyabolical 10+ year member]

Blowthroughs, bed boxs, extended boxs...different names, all same concept.

The reason i don't like them is because it defeats the purpose of the truck....it is a truck for the bed. You are cutting a hole through the rear of the cab and connecting it to the bed by way of a long box....

I have just seen some bad things happen to those. I know a guy who had one built...$2000 dollar job...he takes it down the road and hits a pothole and tears the box to pieces because his bed torqued.

Most are smart enough to use an accordian type boot that flexes with the chassis, but these can lend to really bad road noise, no matter how much dynamat you use.

Others build the entire box in the bed, and then use a flexible tube to connect to the cab...this works okay, but the spl and sq are somewhat lacking.

 

[PowerNaudio 10+ year member]

here is some info i found i think on this site and i saved as a text file just didnt save who wrote it.

ill post it but dont ask me about it, because i havent done it.

You can only make the hole as big as you
BED wall will allow,

Your CAB wall is bigger, but you want the

holes to be exactly the same size, within

about 1/8 difference as possible.

Basically you get in your bed, and make a

decision on how big your hole is going to

be.

I have a step side, so I didn't make the

box wider than my wheel wells, so I could

slide the box in and out as i needed,

without remove my tono cover, or needing

someones help!

So I just followed the bed floor ribs up

the the bed wall and drew a verticle line

from the floor, to the little lip at the

top of the bed wall.

It's up to you wheather or not to leave a

lip at the bottom of the hole.

If you leave a lip, it should be at least

3/4 inch high to attach the crimp seal on

the accordian rubber seal, similar to a

door jam seal crimp.

then I usually leave a 3/4 inch lip at the

top of the bed wall down from the angle on

the top bed rail, you'll see what I mean

when you look at the rail.

I tend to cut the hole level with the bed

floor, so the box can slide in flush with

the cab.

If you leave a lip, and want to slide the

box into the cab, you'll have to shim the

bed floor with wood, or metal, effectivly

raising the bed floor so the box will

slide in the cab.

Many people make the box bigger than the

hole and push the box up against the bed

wall, it is harder to seal the subs from

the bed to the cab this way, but you get a

bigger box.

When I cut the bed wall level to the bed

floor, I use a metal flange,

duct sheet metal, galvanized and make a

flange, rivet to bed and rivet to cab then

use urathane caulking to seal.

then the acordian seal only has to go up

each side and across the top.

and no, the twisting of the cab and bed

did not mess this up, as I had this in my

truck for 4 years, and no problems.

so, I used an angle grinder with cut off

wheel to cut the bed wall out.

You SHOULD round the corners, not 90

degrees, the crimp seal on the acordian

rubber seal doesn't seal as good in 90

than a nice rounded corner.

I used the bottom of Tim horton's coffee

cups to make the curve.

I then use a two inch hole saw to make the

curve cuts.

So after you have the hole cut in the bed

wall, THAT is your tamplate for the Cab

wall.

I then use the hole saw to make the corner

cuts in the cab wall from inside the bed.

Make the 4 corner cuts, useing the bed cut

out as a guide and they should line up

real good.

I then use a sawsall with a LONG fine

metal blade and follow the line from the

bed wall cut from corner to corner on the

cab wall from inside the bed.

there are two layers of metal in the cab,

you'll see this when you remove your inner

trim and carpet from the back wall.

So you have to use a LONG blade

Use a fine blade with the sawsall, if you

use too coarse of blade, it may catch the

thin metal of the cab wall and warp it.

So, now you have a blow through.

Clean up all the edges with a grinder, or

whatever.

paint the edges, and let dry.

If you use silcone, clear or black with

the crimp seal, there is a little movement

between the cab wall and bed wall, I find

that silicone breaks down quicker,

I always use windshield urathane, Than

stuffs holds good!

So you'll want to cut your acordian seal

and tes fit first before applying urathane

of coarse.

If you left a lip on the bottom, you

should put the joint in the middle, so it

has nowhere to leak, then just urathane

the joint closed.

You'll want some wood and sticks to "prop"

the seal when you get it in place.

I always mush the urathane into the crimp

seal, then put it on the metal, now, it's

called Crimp seal, cause you can Crimp it

to hold better, but the urathane will grip

good enough for you.

Once you have it all on, box line the

whole seal with wood and jam the sticks to

press on the seal while it dries, in the

corners too, this will make a good seal.

Clean up your edges of urathane, if you

used the right amount, you shouldn't have

to touch it!

To run wires to the subs.

If you bring your box flush to the inner

cab wall to make it all pretty, you can

get the wires into the box easily.

If you have the box in the bed, you have

to run you wires under the truck or:

I use black pool hose, or Shop Vac hose.

I cut the hole with a hole saw, beside the

blowthrough hole as close the the inner

bed side as i can and as close to the

floor as I can.

I think the hose is 1 3/4 hole, but not

certain.

Then I cut straight through the cab wall.

Then I push the hose through both holes,

urathance for a seal and let dry.

then I trim away the hose from inside the

cab flush to the urathane seal.

TIP: If you leave your box in your bed,

and the box is bigger than your hole, you

should make a flange, or port to bring the

sound dirrectly into your cab, this way

you won't lose any bass into the bed.

I used a ratchet strap on the two tie down

hooks at the front of the bed to hold the

box tightly against the bed wall, worked

great.!

I made two boxes for my truck, one for

everyday listening and one for competing.

My every box had two 10 inch PG XS which

sounded real good.

and my competition box had one 15 stroker.

If you make your box to come in flush with

your cab wall, you don't have to recess

you subs into your box, make them flush

with the wall and make a port, sounds

good!

Hope this helps!

 

[Subarufool 10+ year member]

thanks guys!!

 

[HotCarl 10+ year member]

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