ok im not great at this stuff but to me it looks like you are causing that vortex on runner 1 cause you have a ramp to start the vortex then you have the bump to turn the air again and then it fallows the curve of the plenum and then the cycle starts over again... so im thinking you either need to change the angle of your ramp... maybe make it smaller... put holes in it ... change the angle, some thing along those lines. another thing im thinking is to completely change the flow and move or maybe even ad another ramp but put it on the outside the plenum thus changing the vertical cyclone into maybe a more twisting motion that might get the air into the first runner better. cause right now it seems to just be swirling around the outside of it and not wanting to go down the hole lol