Below, is the installed makeup air, bilge blower, mounted in the frame of the rear seat, on the driver's side of the vehicle.
Here is a zoomed out view of it's placement. The blower is mounted, so that the air flow direction, is from the vehicle interior, to the engine compartment behind what you see here (don't mind the upholstery, I have a lot of repairs yet to make).
This is the same blower, as it is mounted inside the frame. The string, and pullchain that you see, is no longer used, but I used to operate the intake air regulator with it (described in a separate project found on this website).
Here is the 2.5" hole saw that I used to make the needed holes, along with the later required extension.
Now you see the chassis before the next hole I make in it, which is on the left side of the rear seat. You can just see the seat belt bolt, at the bottom of this picture.
Here is the hole drilled in it, and you can also see the hole behind it in the engine compartment wall, that I used the extension to be able to reach (there is a set screw for the extension lost in there somewhere, even a magnet could not retrieve). If you consider doing so, be sure to drill far enough to the left (driver's) side, so as not to drill into the gas tank!
Here is a view, that few people normally see. This is the wall on the engine compartment side, that is between the outside left rear panel, and the spare tire well (digital cameras are great for views that you can't get your head into, or at least easily).
This is the same view, with the hole drilled through it.
With a hole through both walls, I was able to put a piece of 2" PVC pipe into it. This is now the passage that the air will use to flow from the blower, toward the engine compartment.
After all that, here is another option you may consider that is much easier. This is inside the shelf cabinet that is at the right rear, inside my bus. I used the same hole saw, to make these holes, that I inserted flexible heater duct tubing into (a hose clamp around each tube keeps them from slipping through). It does not matter, if your bus does not have such a cabinet, the holes would be all the easier to make. Once made, the holes can be fitted with PVC tubing, and fittings, if desired. This is another location that the blower could be mounted, you would just have to run your switched wire from the front cab, to the blower (if you use the speed controllers described elsewhere on this website, you would need a ground wire from the controller to the blower as well).
