> > Here is my current delema(s):
> 1. It's getting hot again. Does anyone have a poor mans alternative to
> the Service Bulletin and (unnavailable) kit to open up the lungs of the
dash
> a/c???
snip
> Anyway, thanks in advance as always. Larry Nelson, PB 75, Springfield, MO
Hi Larry,
I have been waiting until I get in some more testing completed before
mentioning these mods here. You sound like you need a project so here are
two ideas for your amusement, consideration, etc. etc.
#1 mod turns the floor slot into a ram air ventilator.
#2 mod uses the floor slot to add more heating and A/C outlet area from the
front air box. This greatly enhances the flow of hot or cold air from the
existing air box and blower.
There are tradeoffs such as the ability to recirculate interior air is lost
with mod #1. This suits me fine because I prefer vehicles which bring in
outside air under pressure. Others will be outraged at the idea. With
a little extra effort you could add a second door in the front cover and
keep the recirculate function when using heating and cooling.
It is also necessary to block the flow of air from the floor slot after mod
#2 when you need maximum air flow from the existing outlets including the
defroster. I am still looking for a suitable adjustable grill for the floor
slot to accomplish this. Meanwhile I stuff a cloth in the opening when
needed.
The GM "fix" adds about a 24 sq. in opening behind the heater core and this
"fix" adds 50 sq. in.
The floor slot has 34 sq. in. of area. Recirculate door has 27 sq. in.
#1 FRONT A/C BOX RAM AIR MODIFICATION
Before modification the floor slot is used to recirculate interior air to
the blower inlet.
After modification when recirculate door is open, ram air flows in through
the recirculate door and out the floor slot.
This helps keep interior under positive pressure and reduces chance of
carbon monoxide or sewer gas entering coach when underway.
That portion of air box front cover located in front of the recirculate door
is cut away and replaced with a coarse screen.
Recirculate door vacuum line is changed from number two selector valve port
to number two temperature valve port.
This by passes mode selector switch so the recirculate door opens when
recirculate position is selected regardless of where mode selector switch is
setting.
When recirculate is selected, door opens and ram air flows through door
opening and out the floor slot opening.
Blower motor can be used to force more outside air out vents.
With a little extra effort you can add a second door in the front cover and
selectively retain the recirculate function when heating and cooling or ram
ventilation.
#2 FRONT A/C BOX ENHANCED HEATING AND COOLING AIR FLOW MODIFICATION
Front cover and heater core were removed. A new 50 sq. in hole was cut in
air box rear wall behind the heater core. This opening lets additional
heated or cooled air flow out through the floor slot opening. This doubles
the outlet area and seems to about double the air flow when using the
existing components.
Floor slot opening must be blocked for maximum defrost or to increase air
flow from existing vent openings.
My description may not be very clear unless you have been looking inside
your air box. The manual helps somewhat but the pictures were not very
informative in this area.
Anyway, hope this provides some food for thought for your A/C cooling
problem.
Don Miller
75 Glennbrook project
Shenandoah Valley of Virginia
> 1. It's getting hot again. Does anyone have a poor mans alternative to
> the Service Bulletin and (unnavailable) kit to open up the lungs of the
dash
> a/c???
snip
> Anyway, thanks in advance as always. Larry Nelson, PB 75, Springfield, MO
Hi Larry,
I have been waiting until I get in some more testing completed before
mentioning these mods here. You sound like you need a project so here are
two ideas for your amusement, consideration, etc. etc.
#1 mod turns the floor slot into a ram air ventilator.
#2 mod uses the floor slot to add more heating and A/C outlet area from the
front air box. This greatly enhances the flow of hot or cold air from the
existing air box and blower.
There are tradeoffs such as the ability to recirculate interior air is lost
with mod #1. This suits me fine because I prefer vehicles which bring in
outside air under pressure. Others will be outraged at the idea. With
a little extra effort you could add a second door in the front cover and
keep the recirculate function when using heating and cooling.
It is also necessary to block the flow of air from the floor slot after mod
#2 when you need maximum air flow from the existing outlets including the
defroster. I am still looking for a suitable adjustable grill for the floor
slot to accomplish this. Meanwhile I stuff a cloth in the opening when
needed.
The GM "fix" adds about a 24 sq. in opening behind the heater core and this
"fix" adds 50 sq. in.
The floor slot has 34 sq. in. of area. Recirculate door has 27 sq. in.
#1 FRONT A/C BOX RAM AIR MODIFICATION
Before modification the floor slot is used to recirculate interior air to
the blower inlet.
After modification when recirculate door is open, ram air flows in through
the recirculate door and out the floor slot.
This helps keep interior under positive pressure and reduces chance of
carbon monoxide or sewer gas entering coach when underway.
That portion of air box front cover located in front of the recirculate door
is cut away and replaced with a coarse screen.
Recirculate door vacuum line is changed from number two selector valve port
to number two temperature valve port.
This by passes mode selector switch so the recirculate door opens when
recirculate position is selected regardless of where mode selector switch is
setting.
When recirculate is selected, door opens and ram air flows through door
opening and out the floor slot opening.
Blower motor can be used to force more outside air out vents.
With a little extra effort you can add a second door in the front cover and
selectively retain the recirculate function when heating and cooling or ram
ventilation.
#2 FRONT A/C BOX ENHANCED HEATING AND COOLING AIR FLOW MODIFICATION
Front cover and heater core were removed. A new 50 sq. in hole was cut in
air box rear wall behind the heater core. This opening lets additional
heated or cooled air flow out through the floor slot opening. This doubles
the outlet area and seems to about double the air flow when using the
existing components.
Floor slot opening must be blocked for maximum defrost or to increase air
flow from existing vent openings.
My description may not be very clear unless you have been looking inside
your air box. The manual helps somewhat but the pictures were not very
informative in this area.
Anyway, hope this provides some food for thought for your A/C cooling
problem.
Don Miller
75 Glennbrook project
Shenandoah Valley of Virginia
