Belt driven pressure washer

I have a belt driven Honda 3000 psi using a buffer tank. The pressure washer pulls the water from the tank. My question to someone is, because I am adding another 8 gallon per minute to my trailer. To save room I want to put both pressure washers on top of my water tank which would be about 4 foot above the bottom of the tank. Considering that my pressure washer pulls the water it’s self do you think it would pull up 4 feet? I feel like it would with no problem, right now it is level with the pressure washer so it Hass to only pull from a level source. Again my reasoning is to save for space when adding to pressure washers. Can anyone help with advice?. Also I will be using inch and a half and collapsible hose from tank to pressure washer as I do now.