Good Morning, wanted to share my recent experiences with the air restriction. This is the chronology:
1) Jan 2014 bought coach air filter sensor at 19"
2) March 2014 replaced filter with C15 size air filter and brackets, air filter sensor reset and returns to 19" first run out of the barn
3) Had old muffler replaced with 5050xl resonator, reset air filter sensor and returns to 19" again
4) Replaced air filter sensor, new one measures 19 " also
5) disconnected the 7" hose connecting from the upper air intake opening, reset air filter made long run, sensor now shows 10", more of what I expected
6) Reconnected hose for short 50 mile run air filter sensor returns to 19"
7) Connected intake hose again back to 10"----Hose stays off for now
I really don't like the air filter taking fresh air off the rear of the coach as we live on a short dirt road and when returning with the side radiator fan at full rpm allot of dust is generated around the back of the coach. But air filters are for that. My 1988 Newell had its filter in the engine bay with no outside scoop and its was fine maybe a bit shorter filter life, who knows.
Checked the 7" hose coming from the outside intake and it is clear of obstructions. But looking at the hose installation it is folded into an ellipse when it come through a body panel and turns immediately into the filter housing. I am thinking about a smooth tube, not corrugated, to replace existing but not sure if I will. The data above is adequate for me to leave the hose off.
Larry Haynes
Santa Fe, NM
2006 Beaver Patriot Thunder 525 Cat