Footbox fresh air vents

Although there is some debate about the need for fresh air in footboxes, and the best way to achieve it, I decided to put them in:  I live in the mountains of the West and there will certainly be times when the temperature differential between the footboxes and outside air will make the vent system effective.

A  search on footbox vents yields a number of threads but none (that I could find) provided a lot of detail as to what the builders did.  So, my objective here is to provide as much detail as possible so that someone can replicate what I did if so desired.  The photo album is here.

The table below is a list of the items that I purchased:

The crux of the project was finding the butterfly valve to control the air flow.  One would think it would be relativly easy to find the right part but it turned out to be surprisingly difficult.  The flue damper from Dickinson Marine ( is the key part.  

On the passenger side the part sequence is this:

1.  Create a 3 in. hole in the footbox upper panel;

2.  Attach a reinforcement plate (mine was made from 0.04” Al sheet from an unused panel);

3.  Attach the Spectre Performance air duct mounting plate (SPE-8148);

4.  Attach the 70 deg. Al elbow (SPE-9480) to the mounting plate;

5.  Attach the flue damper to the air intake tube using the Spectre Performance coupler (SPE-8776);

6.  Attach the Atwood 3000 bilge blowers to the chassis at the F-panel (I used nutserts inserted into the 3/4” frame part behind the F-panel);

7.  Connect the flue damper to the Atwood blower using the fresh air hose from Finishline.

PS overview

On the driver’s side:

1.  Create a 3” hole on the DS front panel;

2.  Make a reinforcement plate and rivet / bolt it to the front panel;

3.  Create a flue retainer using the ABS cleanup adaptor;

4.  Secure the flue damper to the front panel;

5.  Attache two of the 70 deg. air intake tubes extending from the flue damper, using the 3” couplers;

6.  Attach an appropriate length of the FA hose to the end to the ’S’ created with the intake tubes;

7.  Attach the Atwood 3000 to the F panel;

8.  Connect the forward end of the FA hose to the blower.

The photo immediately below shows the flue damper in place through the front Al panel and held using the ABS ring from the cleanup adaptor.

The photo below shows the parts as connected.  The ’T’ bolt clamps were used to connect the Finishline (FA) hose to the adjacent parts.

DS vents

Below are photos of the piece that I made to connect the choke cable that will be used to actuate the damper valve with the arm on the valve.

There are two bicycle links. The one that is attached to the damper arm is fixed, i.e, it doesn't rotate as you can see by comparing the two photos. The upper link is free to move and the choke cable end is fixed on that link (it doesn't rotate about that link). So, when the cable is pulled, the upper link rotates relative to the lower one allowing the damper to open fully. 

Also, when the choke cable is pushed in, the rotation of the upper link allows the damper to fully close. It turned out that the link spacer (separating the two sides of one link) is exactly the thickness of the damper valve arm so that the damper valve end of the link that is attached to the damper valve arm can be fixed (not allowed to rotate) and the other end of that link, attached to the second link, can rotate.