Super Max 8900C-640 WS Pressure WasherPrice excludes freight. Powered by a 10 HP gasoline engine, the Super Max 8900C 640 WS is a portable cold water wet sand blaster pressure washer that provides a higher pressure of 3000 psi and lower flow rate of 3. 5 GPM than the 8900C 525 WS. This pressure washer machine has the ability to actually remove layers of material (like rust, corrosion, paint layers, heavy deposits and more) from surfaces. It can restore surfaces back to shiny bare metal.