This will involve some financial investment in better equipment, but it will cost less than a new vacuum pump and yield far more results. First, I would purchase two core removal tools. They cost about $50 each. Removing the Schrader core while you evacuate the system is the single most important step in reducing the restriction and reducing the time it takes to evacuate a system. This $100 investment should cut your time in half, even if you don’t change anything else.
The next recommendation is to get a short ½” hose to connect to the ½” port on your vacuum pump. Appion makes a 6” hose with a ½” connection on one end and a 3/8” connection on the other. If you are using four port gauges with a 3/8” vacuum port, this short hose will connect right to it. This costs around $35. So for $135 you can easily cut your vacuum time in half if you are already using four-port gauges with a 3/8” vacuum port.
You don’t have a 3/8” vacuum port on your gauges? If you are using valve core tools you don’t really need gauges to pull a vacuum. The valves in the core tools allow you to blank off after the vacuum is pulled and connect your charging hoses and refrigerant. With that in mind, put a 3/8” tee on the short hose which is connected to the vacuum pump. Finally, connect two hoses from the tee to the core tools. Appion makes ½” hoses with a 3/8” connection on one end and a ¼” connection on the other which will allow you to do this. These are about $75 each. Since you are using valve core tools, you can connect your vacuum gauge to the side port of one of the core tools.
A couple of final notes. Change the oil in your vacuum pump! Vacuum pump oil gets dirty every time it is used, and dirty oil reduces the vacuum pump’s ability to pull a good vacuum. Not to mention letting running the vacuum pump with dirty oil can shorten its life and you WILL need a new vacuum pump. You should always start out with fresh oil every time you use your vacuum pump. For large jobs, or particularly dirty systems you may need to change the oil more than once. And of course, use a vacuum gauge. Without a vacuum gauge you don’t really know when you have a good vacuum. You can get a micro BlueVac vacuum gauge for around $100.