I've always thought that a felt or paper filter clunk just helps reduce bubbles. I filter the fuel so often it is ridiculous. 1. Pump to JM tank 2. JM tank to main tanks in the plane. 4. UAT 5. Jetcat filter. 6. Filter in motor. This stuff is probably so clean that you could drink it by the time it hits the injectors. So felt clunk as a filter? Maybe. Bubble reducer? Probably, more than likely why I would do it.