Well apologies im taking so long to grasp this, but im not giving up till i get it. I understand what Gavin says about the negative pressure in the crankcase and what way the vacuum goes etc.. So from that this is what i have sussed in my head about the two can method... One line takes from the air filter relocation bend feeding into a can, which then runs to your intake.. The next line takes from the PCV valve and into a can and then on to the inlet manifold. Your line from your air intake needs a check valve in it to prevent flow back to pre turbo meaning the oil/gas resides in the can. No need for a check valve in the other can because the PCV valve is doing that job? Im sorry if this seems easy to grasp, but my car had a half assed setup previous so i never had anything to learn from really off of mine. I wish this had come to light sooner, wouldnt have wasted my money on a racetech! John