Need upgrade recommendation

[slowfkncar]

Plenty of options here if you are willing to upgrade the amp. 2-3k and two fi-q's will sound very good and have more output then your type r's. Buy a good amp and new subs ,dont forget the 0 guage. Get it all done one time so you dont have to keep spending money upgrading everything one by one.

Qs are really in another price/performance level will easily take 2K each, 4K amp two 0ga runs, alt etc.

Either way he goes, it will be much better then the type-r's. I only recomended the q's because to my ears they are very musical even in a ported box. Honestly its up to him if he wants to run 2k or 4k.

[csshakka]

I did some calculations on your box and at least it seems tuned lower than you state and your port area is kind of low, also subs up improves output sometimes, you will be tuned to about 30Hz or maybe less, also you use the center line of the port to measure it's length not the inner walls, you should be tuned instead to 34-35 Hz if aiming for output.

Those subs are good enough to compare with SA-12s or most <1K <$200 subs you can find.

If you really want to step up your output go for 15s if you have the space, like Fi SSD 15s which are not expensive and could take 1500W each.

Good catch on this. I went back to my winISD project and I had the type r modeled @ 1.54 cubes with a slot port of 2 in x 11.5 in, length 31.5, which yielded a tuning of 33.6Hz. Yet, the box was built with a 1.75" wide port. Somehow when I made the CAD of it, I must have accidentally messed up a couple numbers. Also, you mentioned using the port's inner walls. Are you supposed to use the inner walls (like the red line in the picture) and not the centerline?

http://i59.tinypic.com/o75d1j.png

Those Fi SSD 15's look pretty nice, but I think I could only fit one of those, which I'm not sure would be worth it over two type r 12's. I'm limiting myself to the trunk so that I still have a backseat haha. Not a fan of having the box taller than the backseats either and advertising my equipment to the world. This pretty much leaves about 4-5 cu ft to work with in the trunk area.

Like you all keep saying, upgrade the amp, buy new subs, 0 gauge and 2nd battery. For now, I think I'm going to do the wiring, add a second battery, and build a new box (little bigger 1.7 cu ft'ish, 35-36hz tuning, subs up, port back). I already have two runs of 4 gauge so I can tie those two together at a second battery at the back and then split to sub amp and 4 channel amp. A second battery and building a new box won't be that expensive, and then once I start my summer internship, I'll have more money to start looking at new amps/subs.

[Joe X]

No it's measured along the center line but the thing is that your port ends one diameter before the bottom corner so the effective length extends further along the corner itself so tuning should be lower.

And yes, a new box can definitely improve performance and if your voltage is dropping at higher output surely you will need electrical upgrades, set your gains with DD-1 to make sure you are sourcing all that your amp delivers.