with a box at 27x21x27 what size port would i need to run a 18"btl at 2000 watts? this is just the available area for the box. with displacement it puts the box at 7.13ft^3. and i am using 3/4 mdf. or would it be better to run both btl's in the same enclosure and port it. if so the box would change to 27x42x27. what port length would be needed to run it at 32hz?

are you sure that comes out to be 7 ft?

and like i said in your last post id check on your top board and reinforce it with another piece, scott told me to do so with my 2 q's

are you sure that comes out to be 7 ft?

i measured my trunk and i have a total of 14 cubic ft available. with the box being needed to be removed i took away some space. but it is 14 ft^3. 27x27x42.

well 27x27x21 if completely doubled up (.75 MDF doubled up) gives you 6 cubes to work with internal. if you plan on really powering the BTL hard i would double the box up and go with the 32 hz tune but if you are not planning to drive full tilt wattage to the sub then i would double the sub side and the piece behind it and brace the rest (which will give you a little more space to work with internal) but leave the tuning within 32 to 36 hz range. if the internal was 7 cubes total to work with and you did a port roughly 18x4.5x20 to 22.5 deep you would come out smooth.