Mak 4 gph at 14'

[stephane]

Bigger the pipe the less you will lost your flow as water will travel more slowly inside the pipe so you eliminate a lot of friction.

Canadian even if the pipe is 20 inch wide the pump will not see any difference. Pump are only sensitive to the head and friction not the size of the pipe.

pressure in watter calculate in height not in wide, you will have the same pressure 20 feet deep in a pool than 20 feet deep in a 20 mile long lake