2 gallon res: I missed that post, yes, too small for big pump. Breaks all the rules of thumb', could be done, but the tank design to do that is way beyond the scope of this board.
OP: think need to go back and define the goals at hand. There has been discussion of a 6 hp, and a 14 hp, 11 gpm, maybe larger, 4.5 cyl, maybe go 5 or 4........ going all directions here. What exactly needs to be scrapped or replaced or upsized? Sound more like simply a pump change is all you need.
14 hp is a waste with the 11 gpm pump, not necessary. 6 hp is max the 11 gpm will draw. That's a good match.
14 hp can run 22 gpm pump, but needs larger res and upsized filter, valves, hoses, etc.
4.5 inch cylinder seems like more than enough force. 4 inches is IMO quite adequate for most homewoner stuff. 4.5 is slower, 5 inches on 11 gpm would be like watching paint dry. Way better than maul still. And 5 inch cylinder may tear up the structure with higher forces.
As noted above, the key is the two stage pump, biggest improvement for the money.
It sounded like you were doing a total rebuild and upgrade, but doesn't sound really necessary or approriate. After all the 'possibilities', I'd sell the 14 hp, put on the 11 (or 13 if you haven't bought the 11 yet) pump on the 6 hp, stay with existing cylinder and structure and go to work. Use it a year, make a list of what you want to change, and if it's a big list, build another one. Think way easier than all the mods here. Otherwise, 6 hp is way better than any maul and wedge situation.
and well put, everything matched for size and hp and speed.
k
