Hello everyone, I am new posting here, but I have been reading threads here for quite some time.  I will get straight to the chase:  I want to build a WO for my 4 Cerwin Vega Vega 124s.  This is to go in my Astro Van.  The subs have a very high sensitivity rating of 94db and an Fs of 23hz.  They already hit hard and low, but I can't help but think the WO would really make them sing.  The plan is to build 2 WOs and stack them on top of each other- the 36x24 scaled by a factor of about 1.361 to create 2 boxes 49x32.75.  This will fit snugly between the wheel wells in the van and leave very little waste from a sheet of MDF.  It will also make it easy to service for the 12"s.  

My real question is this: Should I build this?  I like very good SQ with tremendous bass when I want it.  Right now, I have the subs in a half wall box that is seperated into 4 sealed enclosures.  The subs are all wired 1 Ohm mono to a 1600 Watt RMS Hifonics amp.  The subs fire at the back doors and the space between the half wall box and the doors acts as a port of sorts... meaning the system acts (while in the vehicle) like a bandpass box.  It has pretty good SQ and gets seriously loud, but I can't help but want something more.  

I love building boxes and messing around with my system.  I like everything I have seen and heard about the WO and would like to know from the experts before I drop around $150 in supplies.  Any help would be greatly appreciated.  

Mmm... I have also seen most of the posts here about scaling- and how the design doesn't work that way- instead, I should add 2 inches instead of scaling.  I hate to build some sort of hack WO and then be upset with it, especially if I didn't build a WO to specifications and therefore have no real means for judgement in the first place.

Ok, how about this-  I have 51" inbetween the wheel wells.  What if I built 2 of the 36x24 WO (as designed) and stuck them back to back with each horn firing toward the left and right side of the vehicle?  What about cancellation?  Would that be a real concern?  I could at least build one 36x24 and try it out- if I don't like it in my car I am sure my 2 12"s in my home theater setup would like the WO better than their sealed box...   ???

I have all but decided- I am going to build a scaled WO this weeked.  Well, that is the plan anyway.  If I like the box I may try to put all 4 in one box- Isobaric.  It wouldn't help output, but should lower the bass and will get the full wattage from my amp.    What if I build this thing and it is a terrible and glorious subsonic monster?  What if Elephants fall in love with my van?  I am excited.  Even if I screw it up, I still get to smell MDF dust!

Wow.  I think you have fired me up.    I have been so busy with work here as of late that I haven't been able to even think of picking up a saw.  But, to respond to some of your statements:

If I stack two WOs, I am going to put a divider inbetween them.  So, it will be two seperate enclosures.  I just wanted them to be the same size to make the box LOOK like one enclosure and to ease my amp rack design.  I have so many amps and wires- I need lots of room to make it work and look good.

I read that about Steve working with the Imperials with two different drivers and getting a better sound.  Very interesting stuff- but since I already have 4 matched subs that I am running at a desireable impedance load off of the same amp, that is a non issue for me.  

However- the part about building a scaled version and a +2 version has my ears ringing and my brain racing.  I can do that!  And compare them in my vehicle!  I can put the scaled one on the bottom and the smaller one on the top.  Mount my components on my rack and it will be easy enough to disconnect one box and listen to the other for comparison.  And if I like the scaled version, the +2 can go in my wife's car to replace the poor sealed box for her 2 12"s.  If the scaled one goes, it can go in my home theater to replace the poor sealed box for my 2 12"s in my house.  Either way, I can do this with very little waste!  I can justify it and maybe even get my wife's approval!  
Holy crap!  This is working out... in my mind at least.  ???  I hope to do this.  And when I do I will let you guys know with words and pictures.  I don't mind doing the saw work.  I have been missing the smell.