A Laserwash 4000 should have the high pressure pump set between 1000 psi and 1200 psi in order to get the impingement correct at the vehicles surface for proper cleaning. We run at 1100 psi. For what it's worth we use the Water Saver Valve to reduce the pressure to 400 psi for non cleaning passes. This helps provide a shinier vehicle when using a sealant.