A shop vacuum of 5 hp or higher can be an air source for the Flow Performance Basic 2.0 flow bench kit, but there are a couple models available that can produce extraordinary flow rates. These models have the detachable blower unit. These detachable blowers are easy to mount on a special fixture for optimum air flow through your flow bench.
This grey detachable blower is rated at 6.5 hp, and is available on Craftsman (Sears) and Ridged (Home Depot) brand vacuums. When attached to the actual shop vacuum, their power is diminished by the shop vacuum hose. But when detached their full air power can be realized.
With the blower unit mounted on a special fixture, higher flow rates are possible from the blower unit than are possible when the blower is attached to the shop vacuum canister. A special fixture for the blower unit is simple to build for intake (vacuum) flow direction. Reverse direction (positive pressure) is more difficult.
The intake of these blower units is quite large. But it is surrounded with a flat surface that makes it easy to install on a flat surface with a hole cut into it. Making a ring of soft rubber hose fitted around the intake filter cage (there is a filter inside the cage) of the blower makes a good seal (light grey band shown around the intake filter cage).
This is the special test fixture we built to test these blower units. The hole for the blower intake cage is 7.5" in diameter, and the box needs to be a minimum of 4" deep from the top surface to the box bottom. There is a 3" bend attached to the box with a 3" to 2" bushing installed into the 3" bend to accommodate the FE2.0 flow element. With a soft rubber gasket intalled on the blower unit, we simply lay the blower unit on top of the box. The vacuum generated from the blower unit holds it securely in place.