Packard Forum Index » V-8 (1955-56)

Major disadvantage of aftermarket AC systems is that the blower motor is always INside the car. Blower motors tend to run hot.

I'd like to come up with a way to mount blower motor OUTSIDE of the car while still recirculating the interior air across the evap.

The only easy way and something I've thought about is replace the factory heater blower with a larger one and use the fresh air duct. You'd have to make an adapter to get the air over & into your evaporator but could be done easily enough. Advantage would be simple control and greater heater flow. Disadvantage would be your main concern of no way to recirculate the inside air unless you kept the interior motor and dual controls and used that when recirc needed.

Other option would be remove the regular heater, make the blower setup similar to what factory AC did except in heaters place & duct the air over to your underdash. That would work if you had an underseat heater but not for defrost. If a defrost needed would have to get a classic or vintage air unit with integral heater/defrost and AC & duct to that--or maybe a standalone defrost like the early cars had.

Might even be possible to mount the blower inside the heater box so it looks stock under hood.

TOO much humidity here in Tn. to use the stock heater motor at all.

Mounting the AC blower motor in the heater box is a good idea. I'll check into that possibility. Never thot of that. I have a spare heater box top that i can cut a holes in. I hate to cut it because it's a nice one too. Maybe i'll find one that's ruff before i do any cutting. GOOD idea tho. I'll look at the possibility tomorrow.

I'd hate to see the heater box cut too as it would destroy the stock look. Height seems to be the limiting factor. Was thinking if a deep indent blower could be used like the ARA unit, the motor could be recessed in quite a bit or maybe even a flat motor like the radiator fans use would work.

Vintage air also seems to have a fairly deep recess blower on some of their units if that could be obtained. The one in the drawing looks to be about 5 inches or so. Think the biggest issue would be the custom wheel enclosure to match up with the outlet. Being in the center kinda limits options so things might have to be mounted on a tilt. Using the outlet to feed the evaporator would allow fresh air or recirc just by use of the air vent control though.

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When I put a/c in my '48, I plan on using these fans, they can be placed anywhere, in any position, and move a lot of air. You can also put several of them in key locations if you think you need more air flow:

Computer fan is a good idea. I tried one on the OUTside of the evap. Maybe needs to be mounted to the squirrel cage.

On a different note. I went to EnergyVortex.com but could not figure out how to use the website.

The question is: How can we determine the BTU's of a typical auto AC unit???? I've never seen it officialy listed. I was told at one time about 20k BTU's. But i've never been able to verify it from another source.

Be interesting to see how the computer fans work out. How many were you or Eric planning? For me, don't think they would be that satisfactory because don't think the airflow will be concentrated enough to give a strong blast for that quick cooldown to the face--at least not thru any type ductwork. Have been known to be wrong on occasion though so maybe this time too.

The 20k is repeated herehttp://www.eng-tips.com/viewthread.cfm?qid=26952&page=22 and there is some discussion with varying different numbers for the btus here.http://hvac-talk.com/vbb/showthread.php?s=d7b4a080a5fc7631b8e0db785807e14d&t=328492.

Don't recall ever seeing a published number but older units horribly inefficient as compared to newer--mostly because of inadequate insulation, airflow & distribution--so needed & tended to be fairly large.

The evaporators in the 53-56 is probably 3 times the size of the one in your underdash unit and will freeze your you know whats off at the same time the passengers in the far away seats are sweating because the cold air never gets that far.

Thanks for the links. They verified my memmory.

Small computer fans:
The only reason i want one is to eleminate or reduce the HEAT from the blower motor of my 'under dash' Mark IV unit. It throws off a terrific amount of heat. Right next to my foot and my feet sweat bad enuf as it is.

I mounted a computer fan (but now removed it) in right most louver duct of the evap shroud as shown in about the first pic of this thread. It did a good job of moveing air but mostly to the back seat.

The Mark IV unit supplies the back seat just fine because it shoots the air UP, hits the roof and comes back down in the back seat. My sister and Brother in law rode back there and said they had plenty of cool air. I was surprised. They run AC when it's 50 F outside in their cars and damned near freeze me out wearing a coat.

If i open the glove box door and let it flop down on the evap it blows even more cold air at my neck and just over the back of the front seat.

The Mark IV unit is a bit slow to cool the car down if it gets real hot inside. That is probably due to the TOYOTA condensor i am using. The original M/IV condensor was much bigger but didn't come with the car. ONLY the evap and pulley and 1 hose was left on the car when i got it.

One last note. i find it strange that he web site link u posted indicates 20K BTU/hr. Because BTU is 1 pound of water temp change at 1 degree at sea level IN ONE MINUTE. SO the "per hr" part throws me a little.


U have factory AC. IT is currently in operation???? Strikes me odd that hte dash vents are pointed directly at your face. Seems to me that they should be closer to the center of dash for rear seat cooling.

Not sure where to mount extra fans in your case. The air needs to travel over the back of the front seat or bounce off of the roof. I think i'd play with louvering the dash factory vents to do that. Maybe just tape a piece of card board in front of the vents to the dash as a preliminary test.

Not currently operational because of compressor valves and lack of motivation to do something with an old limited hard to get parts for system. When it was operating, would freeze you out in short order and that is/was part of the issue. The original system only had one temp--cold--and the choice of a lot of cold air or a little less cold air. Even turning the heater on (which ducts right into the AC plenum) didn't warm it much.

Trying to decide on fixing this arrangement with lots of $$ or just do a modern conversion like Loyd Smith did yet try and keep parts of original system to camouflage the new. If the car were totally stock, would be easier decision. To the second end, have been doing a bit on redesigning the original dash switch for modern components. Made a third more compact design since the ones shown in an earlier post but still a work in progress.

The factory ducts are semi adjustable. They do bounce air off the roof by design when full open but have a friction fit so the amount they lift up can be varied. While not directly pointed at anyone unless they're sitting in center, there are louvers which direct air side to side for some of the air in the face bit.

Probably already answered this but what do u plan to use for a condensor????