Technical Trunk mounted A/C in a 40! Anybody done it?

I see that Vintage Air has a trunk mounted AC unit.

My 40 coupe has a LOT more trunk room than under dash room.
Is this feasible?

It works for rear air on late model (90’s) Suburbans.

Several results on the Search, but nothing specific to a 40 coupe

What say you? Anybody have pertinent information? Pros or cons?
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Thanks!

 

Don't see why it wouldn't work, only negative I can see is the longer pipework and gas amount.

 

Curious to see the responses to this. Interesting thought.

 

Here are a few things I have gleaned from the search. Feel free to add or subtract.

Longer hoses needed
Return air access needed from seating area to unit
Condensate drain needed
Ducting placement plan needed for efficient cooling.
Rectangular steel, aluminum or plastic ducting OK under seat, package tray or rear quarter panels
Ducting efficiency benefits from insulation from floor heat

 

Didn't some Imperials have rear air in the late 50's early 60's. Possibly some Caddys too.

 

I don't see why it would not work. The only problem I see is that you won't have cool air blowing directly on your face And body parts.

 

I done this numerious times, and thats exzact the problem... when it's hot out the air needs to blow on you.. I did one where the ac vents were in the consol and blowing at you , and did one with defrost vents in the head liner , worked ok..... whats better than putting the unit in the trunk is to put it behind the seat... and if you have to make a box to seal it from the trunk... if you don't you suck the hot air in the trunk into the cab... the best way is to get cross flow , run the ducts on the floor to the front...

 

Reminds me of the fifties Buick's Olds's, Caddie's, and Packards with the big plastic tubes in the rear window.

 

When I was little Grandpa had a '53 Caddy that had the air conditioner mounted in the trunk, on a humid day ice crystals would shoot out of the plastic tubes up near the headliner which made us kid think it was snowing inside the car.

 

Those big plastic tubes went to vents in the headliner above and to the outside of where a person would sit in the front seat. I believe you could adjust them so the air would blow on your head.

 

Since the AC is in the trunk anyway, perhaps a duct could be fashioned to run into the zesty beverage cooler to keep the ice from melting so quick?

 

Chrysler also used trunk-mounted AC in the '50s, my '56 DeSoto has it (doesn't work however...). The plumbing will be a challenge, but the package-tray inlet/outlet leaves a lot to be desired. Ductwork to a better forward location will be a real challenge. The trunk unit is huge (about the size of a 40 quart cooler) possibly to make up for its inefficient location.

And IIRC, GM added fresh air intakes for their trunk units to increase cooling rather than using a straight recirculation system. I believe Lincoln did this also.

 

I ran into Jack Chisenhall at the streetrod Nationals some years back and asked him about the pros and cans of putting a/c in the rear foot wells in my 50 chevy delivery. He wasn't very positive about it and said it was a helluva lot more realistic to keep it up under the dash even tho there wasn't much room there.

 

as i recall, the earliest automobile a/c units (packard?) were in the trunk. you may have seen howard hughes' '54 chrysler that was done that way. he was a diehard germophobe!

 

I've daydreamed about this a short while. Is it feasible to put the electric compressor and what not in the trunk and just run long lines to the evaporator and duct work under the dash? Would keep the engine bay uncluttered yet still have the benefits of throwing snow at your face.

Cost of longer lines and refrigerant would be higher, but is there any other downside? I haven't looked into it, but i've heard RVs use electric compressors. Not sure what volts the electric cars run through their compressors.

-rick

 

This has come up before... It takes considerable power to run the compressor. With a 12V supply, you're looking at amp loads of 150 amps at a minimum, more likely double that. The rooftop units on RVs are all 120V, run off either an on-board generator or plugged into utility power. Most EVs operate on roughly 400 VAC, dropping the current to a manageable 15 amps at most.

 

Evaporator on the floor behind seats in my Bus'Coupe. Takes a few minutes but it will freeze you well.

 

One of these under dash units looks like a better alternative to trunk mount:
https://vintageair.com/builder-series/evaporators-and-heaters/under-dash/

 

There are loads of electric AC options on a now.

I would say make sure your alternator is up to the task for electricity needed.
the long lines and condenser and fan location would leave you routing things all over.

Please post what you come up with.

 

At work, our school bus fleet has plenty of rear mounted A/C units with enough hose to wrap around your whole car, they can cool a rolling green house. What you need is a unit that pulls air in the bottom and back out the top, like the new house units mounted up on the walls, they would cool a car easy enough, just wouldn't have the initial blast in the face cold air. If you could duct it from under the rear seat to the truck, then back into the cabin along the roof, it should work just fine.

 

It is not that difficult to install behind the dash. Vintage Air Compac in my 40. Of course under the dash is a better answer than the truck, in my opinion.

 

An upholstered panel 3-4 inches under the dash covers just about everything. Drivers need cold blowing on them from the front not on the back of the seat or over your head from the back. I looked at a lot of panels and some were in 40 Fords before I made the one in my 56 Ford. Vintage makes a unit for smaller cars that would probably cool a 40 coupe with ease. I believe it had 3 vent tube feeds instead of 4.

 

I put this older version Vnitage Air unit in a friends 38 ford with a set back firewall a few years ago. It did require a short dash extension but it all fit in a less that stock firewall space. The custom truck style dash board also has less space that a 40 dash. You may have to eliminate the cowl vent lever but may be able to use it with an electric drive motor for it. You would probably have to cut the glove box down to just a space to store your insurance and registration papers. Building a hot rod with modern conveniences always rewires putting 10 pounds of stuff in a 5 lb space. It's just part of the fun. Personally my experience with these AC systems in these old 39-40 Fords shows that the cooling systems have trouble cooling the engine on 90-100 degree days without AC. You may find that you have to turn off the AC when you need it most which makes all this effort and expense a questionable effort. I know many will pipe up and say they never have a problem. That's okay , I don't want to start a debate or argument , just stating my opinion. When I drove this car with AC I certainly enjoyed having that cold air blowing on me from the dash vents. I am building my second 39-40 ford now, both will have heaters but no AC. I live an area that experiences about 2 months of frequent 90 to 100 degree days. If a car event day is going to be forecast at 100 degrees I just stay home.

 

Okay just one more thought. This picture should give you some ideas of how to install the unit.If your 40 has the rear package tray you would have a convenient place to mount some outlets. a couple more attached to the B pillar. I see the air intake would suck air from the storage area behind the seat. So if it were me I would have to throw less stuff back there to keep that intake clear. They also make a trunk unit with a heater but I think you already have a ford heater on your firewall.

 

Several pre mid 50's cars used trunk mounted AC units simply cause they e big at that time period and needed a lot of space. The issue for you is do you just need a way to cool down the interior of the car or do you need air blowing directly on you to feel like you are being cooled off. The temp inside the cabin of the car will be the same but you won't have that blast of cold air hitting you from the front.

 

I love my VA unit in my 40 on our 100 degree Oklahoma days, which are many.

 

Over the years, every variation of AC installation you can think of has been tried. The best installation is still with the evaporator and vent in front of the passenger compartment. (Why do you think Chrysler and the others moved it forward?) Even the under dash models are better than the in trunk models.

On hot days, you want that cold air blowing directly on you. Also, the best insulation you can come up with makes it better. Most people don't put thermal insulation on the roof. That is a big mistake. Put the sound deadening insulation on and then add the thermal insulation. You will be glad you did if it gets hot and humid in your neck of the woods.

 

I installed a trunk mounted ac unit in a 49 merc. customer wanted the original look of the vintage heater . I did have to run the hoses a long way but other than that it was pretty simple. the trickiest part was running a duct to the front . I did it over the original hump and cutting the notch in the seats larger .still looked like it should just a bigger hump. you won't have that problem with the coupe but may have to make a console to hide the hoses going forward and into the dash.
when it is hot, any ac, wether it is blowing on your face or not should make the passenger compartment more comfortable.

 

honestly.. its not going to do much UNLESS you can seal up the cabin.. spend time making sure that the door gaskets seals etc actually seal