Do they have pic's of the bottom of the blower? The reason I ask is as I have been told when the blower spins it naturally trys to push the out going air to the front of the rotors under compresion. From what I see in the picture there is no where for the air to exit. It will have some sort of swill efect and I would think be very ineficent. That is why the alky guys are seting the blowers/rotors back.