Four versions of a 1D3D type cyclone were tested at four entrance velocities. The cyclones tested were a standard 1D3D design, a 1D3D with a 2D2D air inlet, a 1D3D with a D/3 trash outlet, and a 1D3D with both a 2D2D air inlet and a D/3 trash outlet. Air containing a heavy load of gin trash was fed to the cyclones. Dust escaping with the clean air was captured on pre-weighed filter membranes. The cyclone catch was also weighed. The design with both modifications had the highest efficiency. The highest efficiency for all designs occurred at entrance velocities near 3,000 fpm.