2 18" Strokers=New Box Need Help! | Ford Explorer Forums - Serious Explorations

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2 18" Strokers=New Box Need Help!


Well-Known Member
January 15, 2002
Reaction score
City, State
Springdale, Arkansas
Year, Model & Trim Level
94' XLT 97' XLT AWD V8
Well i got another 18" Stroker for the insane price of $75 so now i need to build a new box. Now since leenjen isnt here i need someone elses help. The box I have right now is 1.5" mdf thick with the dimension 20" tall 22.5" depth 39" width. I have it ported with 2 4" 7.5" long pvc tubes. He told me it came out around 6 cu. ft. I dont have the software to make the dimensions so could someone help me out? I can give you the specs. you need from the website. Also would i want dual chamber for this setup? What are the advantages if i did go this way? Space is not a problem here i am willing to make this sucker HUGE. I would like this to be about 14 cu. ft. without the stroker and ports in. About 12.5-13 cu. ft. with everything in. Also i want it to be 1.5" mdf thick again. Someone please help thxs. My Xplorer cargo area is 40" Long 41.5" Width

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Hey man,
What do you want to box to look like? Do you want it to take up your whole cargo area? I can tell you how to figure out the Cubic feet.:
lets say the box will be 40" long x 41.5" deep x 18" tall.
40 x 41.5 x 18= 29880
29880 would be the cubic inches of that box. To get the cubic feet from that number you must do:
29880 / (12x12x12) = 17.291666 C.FT.
29880 / 1728 = 17.291666 C.FT.
That is not subtracting the width of the box or for ports
or the sub or anything. Tell me how many Cubic ft. you want the box to be. And the size of the Ports. And i can give you a rough sketch of a box.


First off....all i need to know is what frequency you need to box tuned to and I will give you a good box. Keep in mind that you have strokers and they naturally are not for SQ so tuning them between 25-35Hz would be pointless. 40 Hz would be a pretty good frequency because it should peak right around your vehicles resonant frequency.

Ok...i went ahead and calculated for the box to be tuned to 40Hz...you will have roughly 12.5ft^3 after all the displacements. You will also have 192.5 in^2 of port area. The dimensions....

BOX: outside figures(1.5" MDF)

41.5w X 37.25d X 23h


The effective length of the port is 14.75
The physical length of the port is 12.25(what you need to make)

Forget I even said the effective length...just make the port 12.25 inches deep

38.5 inches wide X 5 inches tall=192.5in^2 of port area.

If you use these figures correctly you will get a tuning frequency of 39.8 Hz, the .2 Hz is inaudible.

I went ahead and made a box with a slot port....because I think they are easier to use than putting in multiple round ports.

Hey beast thanks. Few questions how many ports do I need? What would i need to do to tune it to about 30hz? I only have 4" pvc pipe can you work up sumthing for those that i can use instead of me having to go find some 5" pipe somewhere. thxs. Also is this for aim the subs up or to the cargo door?

Nonono...this is a vented design...with a slot port. There are no pipes involved. You make the port out of the MDF(rectangular shaped). Also...i would not recommend tuning to 30hz, if you do you will take away quite a bit of spl. I would go 35hz at the lowest. If you still want the 30Hz let me know and if you have any more questions about how to make the slot port just ask.

The reason I say it would be better for you to use a slot port instead of a tubular port is because you have such a large box and need such a large port area. This was to have your subs pointing back with the port being in the very back of the box pointing up.

Oh BTW...nice X:) and I like the gauges.

what exactly is the resonant frequency of a 98 explorer in hz?? anyone one know??? any spl competitors???

not sure but tuning it like 40-45 seems to be the consensus from what i've seen.

that box design up above will hit very high spl numbers. It will pretty much sound like hell though... but i don't think thats a problem here.

how are you powering this?

that is an insain box dude =) very nice work looks nicely done..now all u gota do is get to an spl contest and get the things rated =)