Read this post. It should help you understand. When looking at a nozzle chart your gpm will never change because your machine puts out what it puts out. The whole point of changing nozzles is to change the psi not the gpm so psi is what you’re looking at. You just have to make sure it puts out whatever gpm your machine has. If using two nozzles than each nozzle should put out half of whatever gpm your machine puts out. If you have a 4 nozzle bar on a surface cleaner each nozzle should put out 1/4 the gpm of what your machine puts out.
I replied to another member in this thread so that’s where the numbers come from. He has a 5.5 gpm machine.
