there are two things that control the speed and power of a wood splitter. (Because, I am sure somewhere there is a government employee that sets the maximum pressure allowed in a wood splitter sold to the public.)
so all you have control over is the size of the cylinder and volume (gpm) gallons per minute of the pump.
you want to buy a wood splitter with:
the largest diameter cylinder size you can afford and you want a hydraulic pump with the largest gpm volume.
all wood splitters work on the same principle: the hydraulic pump is a two stage pump, meaning it flows one (gpm) at no pressure, high speed, then when the ram shaft hits the wood, the pump shifts to high pressure low speed to have the power to bust the wood.
to get more power from your wood splitter you have to have a larger diameter cylinder and a higher volume (gpm) hydraulic pump.
just a heads up: when out looking at wood splitter just ask the saleman about these two numbers and you will see the difference in machines.
the units with higher numbers will have larger hp motors and higher cost. but will split wood faster!!!!!!!!! less waiting time for the ram to return after splitting the wood.
good luck and be safe,
these are very dangerous machines. always wondered how long it would take for the government to require a guard cover on the ram as it splits the wood.
I was a safety officer for many years, so I know a thing or two about guard and pinch points.