'upgrade' my air compressor? clueless in Colorado!

[DenverGP]

I think a typical 1/2” impact will pull 5 or 6 CFM so you’ll likely be pushing maybe 45 or 50 psi through it effectively cutting its performance in half.

The CFM of the pump doesn't effect the PSI going to the tool, as long as the tank has at least as much pressure as your output regulator is set to.

The CFM of the pump will definitely effect how long you wait for the tank to refill in long continuous uses.

[ray1970]

The CFM of the pump doesn't effect the PSI going to the tool, as long as the tank has at least as much pressure as your output regulator is set to.

In a round about way it does. If your output is 4 cfm and you’re pulling 8 cfm it won’t be able to keep the pressure up. In other words, you might start out at 100 psi but once you start pulling more air than it can make that pressure is going to tank. And with the 17 gallon tank the OP mentioned it isn’t going to take long.