I am working on a Subie conversion and am trying to figure out AC. I live in the desert (Phoenix) so AC will add a lot of usability to the car. Ideally I would like to blow air through the existing vents. I have searched a lot on the forum and see a lot of starts, but few functioning units. I am traveling to Texas today so I am going to check out Vintage Air and Old Air Products to see what products they might recommend for me to modify. Plan two is to hit the Pick and Pulls and search for the most compact evaporator I can find.

Any help or general suggestions is greatly appreciated.
Thanks
Ed

I am looking forward to this project thread. Good luck.

Just went thru this last year, Ed. I couldn't locate one that fit where the old air/heater box sits beneath the WW's. Maybe there is one now but you'll have to check. Vintage Air has a compact unit that is close but still .5" too tall. As far as under the dash: An OEM unit is a nice fit but 40+ years old. The smaller units protrude out too far. IIRC, they stick out ~1.5" past the knee pad which, IMHO will look like That being said, they do offer a larger model that will bolt up using the existing knee pad bolts and looks pretty much OEM once set. I listed it in my build thread but forget which model it is. I was able to re-use the OEM defrost vents with minor modifications. Vintage air is quite helpful but did not have any suggestions that would help us. Evidently I was their 1st customer installing that unit in a 914. My only complaint with the unit is the fan. I have to run it on low as it is too powerful for such a small cab. When you talk with them ask if they have any means to lower the fan output on that model. Since it is DC I was thinking a step down transformer??? Kent

Thanks for taking this on. I also was going to pursue this idea with reusing the factory fresh air box and stuffing a small evaporator coil inside it a few years ago, but another member stated that he may reproduce a bigger fresh air box to accommodate a evaporator coil. I think his idea may have fizzled out

I do like the idea of keeping the interior absolutely stock looking, but with AC! I never liked the kneepad hanging unit as it is bulky. I have talked with a company that made a unit for the 914, that retrofitted a evap coil inside the fresh air box. The owner of the company even sent me pictures on how the evap coil fit inside that small box. (extremely tight fit) I'll have to dig up those pictures and post them on here. The owner went on to say that the job sucked and would never do it again!

Evaporator coil technology has changed over the past few years, making them smaller due to new production methods of microchannels. Even though they are smaller, it is super easy to overcharge the system.

Again, very awesome that you are taking this on. But I think you are on crack for wanting to go to the junk yard to take apart random cars to measure evap coils. The smaller the car, the more labor intensive it is to get to these coils. I think it would be better for you to make friends with the guy at your local autopart store, and ask them if you can go behind the counter to measure these coils.

I'll be watching to as would like to add an efficient small unit that would keep my car cool and mostly stock looking on the inside compartment. Best of luck!

There is a reason I'm going with custom made cores. But you're welcome to do as you please.

Fizzled. Stalled pending a running test car and a few minor things.

I am by nature an impatient man. If you come up with a solution that is better I would be thrilled to write a check and have a proven solution. I am new to this board, but I have looked over years of posts and there seems to be lots of starts with few results.

With that said, in the spirit of less than well thought out ideas, I am closing in on a plan. I visited Old Air Products in Ft Worth, Tx today and bought their 700 series product. http://www.oldairproducts.com/catalog/images/CAP-800.jpg

My plan is to cut the unit in half, effectively separating the evaporate Core and box from the fans. My thought is to build a fan enclosure in the fresh air box, duct the air into the fans from the cabin (so it doesn't pull air from the trunk) and duct the air from the fans to the Evap box under the dash. I will give me AC and heat, the downside is their is no separation of defroster so and face level vents (so they will run simultaneously at least initially)

My unit should show up this weekend, so I will play with it then. Clint from Old Air Products was pretty cool, he spent a lot of time with me figuring out a plan.

I will keep it updated with progress any thoughts/suggestions are appreciated. At best it will take some work, maybe look a tad strange but should work and can be made prettier later. At worse, I have certainly spent $400 on dumber projects.

The thought just came to me maybe we should get Mark at 914rubber to build a kit he's pretty good at coming up with good solutions.

That's essentially what I did for the first one. Bought a unit from a Hot Rod Air company and had a new enclosure made to my design.
Owner of the company died and it folded. Finally tracked down the core maker but they didn't survive the Recession.
So that's where I'm at today, working on testing a fresh paper design using modern cores of my sizing.

I'll offer up some pointers as you progress, as I practically have an A/C engineering degree. So many have attempted to retrofit then disappeared

Now if someone would design an effective condenser that didn't require cutting the front trunk up...make it look just like a 73 front bumper...lol

My car came with a/c and I replaced the compressor with a rotary Sanden. I built a frame around the condensor with 1/2" tubing and expanded metal mesh to clean up the installation. My evaporator could be used but I have been trying to figure out something that looks better. I bought the unit in the photos below thinking I could run hoses to the factory vents. The problem is that even as shallow as the evaporator is it's pretty impossible to hide it. If you try to mount it in the center of the dash the u-joint for the steering is in the way. The factory aftermarket unit is offset with the motor on the passenger side so that it clears the u-joint.

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Mark
I bought the same unit, along with a mock up case. I am going to cut the fans off, as well as the front where yours vents. I will let you know if it will work. If I can mock it up and it works I will get a friend who is a plastics guy to build me some ducting. If it doesn't work, and Chris914n6 doesn't have a unit for sale, I will throw the towel in and run an under dash unit

The problem is that the fan motor for the unit is mounted in the center and it draws air from both sides of the 2 plastic squirrel cages. Its going to be hard to design something that pulls that air from the cab when it is mounted to the firewall. I bought the unit I have on an ebay auction a long time ago cheap. I think it is designed for a Ford pickup. I may remove the face from it and mount it to my original 914 under dash unit. The back half of the case is a universal aftermarket design and I think its the same as the 914 under dash unit at least that way I will have a new evaporator core and metering valve.

There are some small under dash universal units that are available. I am not sure if they are small enough to clear the steering u-joint. This one might work:

http://www.ebay.com/itm/UNIVERSAL-UNDER-DA...zAN&vxp=mtr

Not trying to throw a wet towel on this subject but until someone like Chris builds a plug-n-play condenser it is going to be a Royal PITA to remote one of these systems. Besides, under mount IS period correct for our cars.

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I will have a better handle on it when I cut it up this weekend. It is going to be a pita no matter what, I will give it a shot. I will let you know how it goes

I am not too concerned about period correct, kind of went out the window for me with the Subie running gear. My challenge with the undercount is I am 6'3 and most of my friends who would be riding with me are tall as well. Prefer not to limit the leg room with a low hanging unit. Of course if it doesn't work I will install the undermount unit

You guys might take a look at rear AC units found in vans and SUV's. They are generally quite compact as compared to many primary evaporators.

For my car, I used the Hot Rod Air under dash unit which somewhat resembles the dealer installed AC.

Andys

I suggest a Manhattan Project for the "best" AC system for both aircooled n watercooled 914's - I think there are enough of us that a substantial amount of $ could be generated to build an evap housing to work with a potential heater core to be slipped in also. Need the ultimate setup. If we can get it sorted out, maybe one of our friendly 914 vendors can take over the production n sales? Not familiar with enough with the 914 ventilation system yet to really get anything sorted out but this is what I do.

One fan to do defrost, cool & heat. The good thing is that the cabin volume is so small. Very good. Possibly configure for other types of project cars, this has been an ongoing discussion on Classic Mini forums also -

I have a rust bucket that I can donate the front section for fit up, won't have at my house for a month or so maybe not able to make this year's hotness. Bay area volunteer's? Naysayer's need not apply please n thank you.

The key thing is getting all this to fit inside the fresh air Behr box. If you can find a small enough coil, very little modification would be necessary. The better route is to make a custom box to fit a standard off the shelf evap coil and possible a heater core for the water pumpers. It would be cool to 3d print a new box, or use plastic vacuum forming to create two clam shells that snap together.

When making a new box, the question is, do you run outside air across the evap coil, or do you have provisions to bring in return air from the cabin, essentially blocking off the cowl vents?

Tim - I'm just going to fly you out and start writing checks when it's time to do my suby a/c. Not even worth me tying to understand the a/c thing let alone work out a solution.

would you be willing to write a check for a metal 3d printer?

I have a feeling they are pricey?

I'm on a small refrigeration project right now that uses really small stuff, custom sized evaps are doable but better to find one the right size, it seems that the mass produced ones are more dense in cooling area there fore more efficient. 2 - ways build the box with good fans, find the coils or find coils & fans that are cheap, easy n plentiful and build box around them.

How about AC system in either trunk and duct conditioned air into cab?

I think trying to modify the Behr box would be a huge compromise and I highly doubt the wimpy fan in there would deliver the required amount of air across the core.

I also think a recirculating system is the only way to go.

I too have the desire to build my own Evaporator box under the cowl but it's a project on a list of projects. Plus I moved to an area where I no longer need AC.

I have to chuckle at these last few posts. Everything you guys talked about I've already done. I just need to test it and possibly make a few tweaks before committing a few grand to importing custom cores and materials. Plus I need a window of time. I even built a vacuum forming machine so I can control the quality.
I've also worked out an engine lid mount condenser.
It's a well thought out system, I just don't brag much.

I would like to have something functioning in weeks, if you have AC and heat, it fits and works, I will take one. Since I am using the subie I am ok with the condenser and compressor.

Chris, I'm losing faith in your project. It's been 2 years since you first posted about this potential stock looking AC solution. I also question the use of custom made evaporator coils. If you are in the industry, you should then know that these coils will eventually develop a leak. When this does happen, how does one obtain a new replacement coil? Custom work is expensive especially for one off replacement parts.
You're going through all this trouble of making a new fresh air box, why not use a standard "off the shelf" small evaporator coil, which will be available for years to come? There must be some car out there, ie, Ford Fiesta or something that has a coil which you can design this new box around? Unless you are doing this on purpose thus making all of this proprietary?

There are probably 3 or 4 members that could or can make a working model. But, and it is a Big But, anything AC for a 914 is a Fringe Market. I'd bet if Chris develops & sells these he will never recoup his investment. And if he wanted to make money off these; forget it. Probably would be better off taking a 2nd job at a 7-11. I probably had 60+ hours installing an under dash unit and modifying the defrost/vent system for it. Chris will have that much time tied up just removing the damned old air box. Well, that's an exaggeration but you get the idea. He's also been around long enough to see how many people express an interest in a product only to never order it. I for one am guilty of this. Others have said this but it bares repeating. Be supportive of those that "do" provide us our 914 products and appreciative of those trying. And finally just to the ; look back and you'll find this subject pops up this time of year and dies down 2-3 months later. Peace out my brothers. KWoody

You are absolutely correct, I am just too stupid to take the advice and will forge ahead. Luckily I am not looking to sell a product, I just want a 914 as a daily driver. If I can make it work, I will document it and anyone else interested in it can improve upon it and make the world a better place for at least ten of us

I have played with British cars for years, I can't imagine trying to generate an income from this hobby. For some reason I am willing to do a ton of work, spend stupid money, have hours of frustration for something only I care about. I assume I was dropped on my head as a child.

Then the problem will be what about humid areas.

I wouldn.the take this on unless I was retired.....not a nay sayer....just plenty of white fences to paint on someone else accord..

Trust me, it's not custom on purpose. I have catalogs. MR2, Miata, Mini, all wrong shape. I have not seen an evaporator that fit within the 6" limit between the wiper motor and gas tank and the up/down limit with airflow, and that's even with the option of trimming inlets. Plus the core has to work with the various compressors being used. Too little and it freezes every minute.
The cores are not that pricey if you skip the American middleman. I have to buy at least 50 and maybe a few more depending on actual commitments, so there will be a few spares. But in the 20 years I've been a mechanic in Vegas I have yet to see a failed evap.

Mowog4- If I ordered components today it would still take a many weeks for cores to get made and sail over here, so I won't have it in your time frame.

I have a friend that owns a small automotive repair shop, he does at least 3 evaporator coils a month. Dodge seems to be more prevalent with these failures. I replaced one in my Durango a few years ago, cracked the damn windshield when pulling the dash while trying to get to this coil. Wife's minivan developed a leak in the rear evaporator coil last month. I even replaced a evaporator coil last night at Garolds house because it too was a leaker. Either from cost savings or perhaps better transfer rates, the wall thickness of these coils are thinner than what they used to be and will fail over time due to stress of pressure cycling or driving over some hellacious pot hole.

I didn't know you tried other coils. A few months before you conducted your poll, I talked with a guy who did conversions for older cars, and had done this conversion for the 914. He sent me pictures of the modified fresh air box, and I'm pretty sure I deleted the emails and for the life of me, I can't remember what model car he used the evaporator coil from. Even though he stuffed a coil into the fresh air box, there was no additional room for a heater core.

I'm not following the freezing issue. Two things that I can think of that causes a evap coil to freeze would be low charge and or low airflow across the evaporator coil. Overcharging will not cause this issue, because refrigerant has a proportional pressure to temperature relationship. Higher pressure (more freon) equals a higher saturation temperatures.

You will need to meet the minimum CFM across the evap coil.
Low airflow across the evap coil is something you may battle. You will also need to size the compressor, preferably the smallest displacement one Sanden sells.
To protect this compressor with low airflow across the evap coil, I would strongly recommend installing a suction line accumulator. This will protect the compressor by keeping everything in vapor state which will save the compressor from trying to compress a liquid. Installing a smart metering device, TXV valve will also help with low airflow, by throttling back refrigerant flow based on coil temperature.

I'm cheering for you, and anybody else willing to solve this problem. I may come off as pretentious, and I'm sorry for that. I'm overly anxious with this project and would love to see some resolution or atleast some tiny light at the end of the tunnel.

Hi Mark,

Would the entire unit fit on the passenger side and allow a hose to be run across to the driver side?

By your measurements it should fit—just hang down about an inch and a half below (but behind) the lower dashpad.

Oldair has another version of that unit with two vents in the front and two on the sides.

-Andrew

BIGKAT 83 designed and installed a Mustang II hybrid a/c system in his blue 914 that worked very well by all accounts. The details are hidden in the archives and are fairly complete in documentation as I remember...

I have my car exactly the way I want it with the exception of AC. I would gladly pony up the cash to get it if someone came up with a workable, clean solution. You are local to me so I say go do it!! And then let me stop by and check it out.

I am making some progress, although life sometimes is getting in the way. My current plan is an evaporator (probably out of a geo metro) mounted side ways where the Behr Air Box used to go, a big fan mounted to the side of it, blowing into the side vents in my dash. I am working on mixing heat and cold so I have climate control. It certainly will not be period correct, but that went out the window with the Subaru Engine. If you look on line for Porsche 914-6 AC there is a guy named John Lovejoy out of Florida who has done this. I have tried contacting him, but have been unsuccessful. Anyway, I am plugging away. When it is figured it out you are welcome to come by, take a look and I will tell you everything I used.
Ed

I found the pictures that Jerry West sent to me of his modified air box he used!
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Looks like he grafted in some 4x10x6" endboot used for HVAC duct work.

Thank you for the pics, these will help a lot. I have tried to get a hold of Jerry West, but had no luck. He did the AC system on the 914-6 from Florida.

Notice the thermostatic expansion valve (TXV) hanging off the side, sometimes referred to as the H block. This is vital for what we are trying to do. The compressor has a certain designed volume of displacement that needs to be maintained. This is typically done by correctly sizing the evaporator coil to the compressor.

Due to size constraints, we are ultimately forced to use a evaporator coil that is smaller than the displacement of the compressor. This is a bad thing, as it simulates a low air across the evaporator coil condition. In this state, the refrigerant doesn't stay in its gaseous state, and the compressor tries to compress a liquid which is physically impossible. This is certain death for any compressor.

TXV valves will help modulate head pressure by sensing the evaporator coils temperature. As the evap coil gets too cold, a internal bypass within the TXV valve opens.
In addition to having a TXV valve installed, you should also have a suction line accumulator as part of the system. The accumulator will help ensure that only refrigerant gas will enter the compressor not liquid.

I did one in Jamie Rust's car. And I'll be done another one in the next few months. Once I find my notes, I'll post what car I got the evap from

McMark
It would be great if you would be willing to share the knowledge, I would love to know the specifics of the evap and the box you put it in. I would even be willing to kick in some $'s to make the project move down the road, especially if you sent me pics.
thanks
ed

I'm in the early planning stages for a custom system on a customer car.


I intend to replace the stock air parts under the cowl with something hand-built for the evaporator.

I'm also intending to use the rectangle hole in the dash where the stock HVAC levers go, as an air vent into the cabin.

The only controls will be a button to engage the compressor and a 3-position switch for the fan.


Of course, I'll post a thread when I actually begin the work, but right now it's only in my head.

There is also another unit out there that a 914er started to work on, not sure if it was completed or not. I am calling you out Clay, where you not installing one in Betty's car looked like a clean install, with a wiper motor relocation.

Someone needs to figure this out before I my front cabin firewall to fit a Vintage Air compact unit in. I have three of their units here to see if I can make one of them fit.

Under dash unit will fit just fine, just don't like the look, you know it was an after thought. I am thinking about trying to tuck this up in the cowl, then making new front duct section. It is vacuum based servos Have to move the ugly controls.

Micro unit, is just .5 to tall, can fix that with cutting the a section out and bumping the firewall down in that section behind the dash. Might take a slightly deeper cut to get duct work in place.

The Mini unit is to long to fit between the cowl supports, could move them.

I have also thought about, cutting one of them up, and moving the fan to a new location, and maybe clocking it, so it fits. It is all just ABS, should not be to hard to come up with something.

Way down the list for me of things for my build, but still in my plans for my 914.

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I have played with British cars for years, I can't imagine trying to generate an income from this hobby. For some reason I am willing to do a ton of work, spend stupid money, have hours of frustration for something only I care about. I assume I was dropped on my head as a child.
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This made me spew coffee on my monitor. Thanks!

Wow, great info. I have just started reading up on this, other than the packaging it seems straightforward. I have given up on off the shelf, looking to get the thing to work, then fit, then make it pretty.

Here is a car I saw on Youtube, it at least gives the idea I am looking for. Plus, I love the cover he built over the evap and wipers.

https://video.search.yahoo.com/search/video...amp;action=view

[quote name='914forme' date='Aug 6 2016, 09:33 AM' post='2381292']
There is also another unit out there that a 914er started to work on, not sure if it was completed or not. I am calling you out Clay, where you not installing one in Betty's car looked like a clean install, with a wiper motor relocation.

Someone needs to figure this out before I my front cabin firewall to fit a Vintage Air compact unit in. I have three of their units here to see if I can make one of them fit.

Under dash unit will fit just fine, just don't like the look, you know it was an after thought. I am thinking about trying to tuck this up in the cowl, then making new front duct section. It is vacuum based servos Have to move the ugly controls.

Micro unit, is just .5 to tall, can fix that with cutting the a section out and bumping the firewall down in that section behind the dash. Might take a slightly deeper cut to get duct work in place.

The Mini unit is to long to fit between the cowl supports, could move them.

I have also thought about, cutting one of them up, and moving the fan to a new location, and maybe clocking it, so it fits. It is all just ABS, should not be to hard to come up with something.

Way down the list for me of things for my build, but still in my plans for my 914.
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The one I was working on was for my car, not Betty's. Hers has the underdash unit in it, and it works well.

Mine got postponed due to the engine replacement for my car. I got the wiper motor relocated to make more room for the evaporator, but didn't get any farther.

Oh well hoping you got it done.

You may remember that I struggled with this same thing. If you are willing to cutout that area it is doable. You can even use their micro switches on the existing slide controls. In the end I decided that the under dash just made more sense. Besides, the look IS period correct albeit an after thought.