polyfill

i have a 4 ft^3 enclosure. how much "volume" can i add with polyfill? and how much would i need. if possible i would like the woofers to see about 6 ft^3. also, how would this affect tuning? i think it lowers tuning, my box is already tuned to 32, so how much would it be lowered?

Ok. I read somewhere that 1 lb or maybe it was 1 sq ft adds 33% more space...not sure which it was though or if I read it right.

33% is the most you can "increase" the volume.

1lb per cuft is a good ratio.