The original system having poor airflow characteristics, and high vacuum, was modified.
This system is NOT optimum either, I am currently planning to increase to 5" hose and
a larger intake/airbox to decrease vacuum further as I am running 3000rpm+ and want a
healthy efficient and powerful engine. Raising air pressure in the intake is all that
a turbo does, you can do it for free if you can improve airflow. It is important
to get cool air though, hot air behind the radiator can actually reduce your power.

Photo 1 (air intake) shows the flap above the horns, a rectangular opening in the storage
bin, and course screen over the opening. This has done a good job of keeping the air
coming into the airbox clean and dry. It is not a good angle to get photos I'm afraid.

Photo 2 (air box) shows the sheetmetal airbox mounted inside the storage bin.
This airbox uses the top, rear, and left side of the bin (facing bin) for three of its sides.
If I removed the airbox you would see the left side is cut open to allow air in
(previous photo), and a 4" exhaust pipe leading up out of the top through the floor
(soon to increase to 5" or 6"). The frame does get in the way when punching through
the floor, not an easy job and this is why I am using 4". I intend to ovalize my
tubing to make it through the 4" clearance with larger pipe.

Photo 3 (transition piece) shows the carpeted over transition piece from the floor/4"
pipe to the side of the doghouse. It is fabricated out of sturdy sheet metal, a few easy
brake bends. Sheet metal fabricators are easy to find and I've used them a lot for mods on this coach.

Photo 4 (air filter) shows the original air filter connected via flex hose to the side
of the doghouse where the transition piece is. I don't like this piece because it causes
more turbulence, is too small, and is not insulated. I intend to increase this to a
smoother bore 5" piece, and insulate it so that the air doesn't pick up heat here,
I will also be insulating the air filter housing when I have time for the same reason.
This photo also shows the relocated flex-hose to the swing radiator modification.

This is not an optimum air intake either as it causes substantial turbulence, but it
is better than what it had. I will be continuing to use the same basic design as I
modify it further, with larger openings.

When Floyd's FC comes out of storage I will try to get photos of his mod also, he went
down further forward and avoided the storage bin completely. His mod uses PVC pipe and
has no airbox, an easier method although I like the airbox for its ability to avoid
moisture and dirt ingestion (personal choice).