DIY Front Air Conditioning

[morymob]

When ilooked up towards the wiper motor it sure would be a problem solver if that thing could be mounted to the left about a foot.

[engscott78]

Wow, very nice write up.

I stumbled on this page trying to figure out a way to make my A/C work in my '87 after a 2.5 subaru swap. I never thought about doing front A/C. Something I will keep in mind now, with this page bookmarked of course!

[sarmanx]

[kjono09]

amazing
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84 Retro-Westy GW 2.2L (Vincent)
67 Bug 2007cc (WBX in progress) (Davey)

Submariner

[Howesight]

TWO YEAR ANNIVERSARY REPORT:

It has now been two years since I cobbled together my DIY front AC. I wanted to give an update on how it has worked and what has happened, so here goes:

1. Vent temps are still in the same range;

2. There are barely-detectable refrigerant oil weeps at a couple of my aluminum-brazed joints.

3. There has been no measurable loss of refrigerant (Red Tek);

4. The system cools the rear passengers of the vehicle quite nicely through the centre dash vents when the dash side vents are partly or fully closed and the evaporator fan is on high.

5. I do have a small water condensation leak in the hose draining water out of the evaporator box. This might, possibly, simply be water sloshing over the edge of the evaporator, but I cannot view the leak area.

6. No parts have failed whatsoever.

What would I do differently?

1. I would make a proper mold for my evaporator box next time and have it vacuum-formed. This would allow me to make it even more compact and contain condensation water better;

2. I still want to make a circuit that will enable me to control the variable-displacement feature on the factory Subaru compressor.

3. I find that the factory rad fan on low speed is quite noisy. At low vehicle speeds, I think it would be possible to use a sail switch to turn off the fan once a certain speed (actually air speed) is reached, both for noise and for power consumption. 80% of my driving mileage is on highways, and it seems to me to be silly to add load to the alternator by requiring it to power the rad fan when ram air is doing all the work the condenser needs. I notice less current and voltage available for charging my house battery when the rad fan is running.

4. I would not clock the windshield wiper motor since the final configuration of parts does not require it.

5. I would use a different method for closing the fresh-air inlet on the factory heater box. Mine uses a cantilevered flap that gets pushed open by the wind unless I use a rubber band on the sliding control knob.


Would I do this again?

Yup. My compressor just died on my Audi, so no cooling joy there. The contrast with the Westy as a result is crazy. Driving the Westy with A/C is a dream - - windows closed, music on, no sweating - - priceless.
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'86 Syncro Westy SVX

[djkeev]

Thanks for the update!

Glad to hear it functions well.

I feel that there would be an active Cottage industry making front AC kits.

The molded box, blower, Evaporator etc.

Your design or simply copy Behr's design.

Utilize off the shelf common bits and call it good!

Dave[/b]
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[Howesight]

Hey Dave:

I have been thinking very seriously about making a kit. I need to source a good supply of quality Toyota blower fans to make that idea fly, because the aftermarket units are rubbish.

The Behr design uses a large, outdated, inefficient core that you can't source anymore. I tried to use parts that can be readily-sourced, like the evap core found in millions of Audi A4 cars and Passats. Being small, that core allowed me to still have a glove box.
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'86 Syncro Westy SVX

[thummmper]

how totally super cool. nice thinkology

[allann]

Helo. The same custom project in my garage. Great results with your a/c. Nice to see that is possible. Mine was started in 2012. A/C dash part was done 50%. System will be based on audi c4 manual a/c. Becouse my project is remake of everything, i left a/c for the future . Now all power is on fitting ASV 1.9 TDI. Right now i am working for to fit all hoses(coolin, power stearing and a/c). Thats how i find your project. My work is there http://www.thesamba.com/vw/forum/viewtopic.php?t=6...highlight=
One thing i want to ask. How far can orifice tube can be placed from evaporator. On audi c4 it is very close to evaporator? You have fited it in distance. Me too having problem in placing orifice tube for to have better acses in the future.
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Sorry for my English, hope You will understand me

[Howesight]

Allann:

Sveikas!

I spoke to a local AC technician who builds custom systems for hot rods, historic sports cars (old Ferrari's and Lamborghini's, for example) and is very knowledgeable. He said that I could place the orifice tube as much as 500 mm or 600mm away if I wanted to, without affecting performance. The important thing is that the hardline (aluminum) pipes between the orifice tube and the evaporator must be covered with insulating cork-tape:

The pictures in my thread above don't show exactly where I located the orifice tube. The pictures below show the location:

Sėkmės!
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'86 Syncro Westy SVX

[Vanagon Nut]

[Howesight]

Thanks, Neil. Aluminum is, indeed, a different animal. I found that the ability to immediately stop applying heat quickly to be almost as important as applying the heat, so I don't think I would be able to use the stove element trick.

The colour change in the flame as the aluminum comes up to the brazing temp (quite a noticeable change, in fact) is the best temp indicator, in my experience. Anyone doing this should have some junk fittings on hand for a few practice attempts.
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'86 Syncro Westy SVX

[Vanagon Nut]

you're welcome howesound
good heat tip.
Nice to know of alternatives for joining
Aluminum.
Your build thread is adventurous but I'm
sure you'll complete it!
Neil.
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1981 Westy DIY 15º ABA

1988 West DIY 50º ABA

VE7TBN

[allann]

[iulian]

Hi everyone,
I thought adding my own experience on DIY front AC install. My main goals with this project apart obviously from decent cooling inside, was to keep the stock look and function of the dash, meaning adding a cooling function to original heater box.
I investigated first the solution with a separate evaporator unit behind the glove box but I couldn’t find a stock one to fit in that space and I lack those skills to manufacture a custom evap plenum
I bought a panel van heater box to work on(I am lucky, there are plenty of people around here dealing with Vanagon used parts, it was easy and relatively inexpensive to get one, later on why choosing one from a panel van). Initial thought was to find an evaporator that could fit inside the box in between the fan and the heater core, had no luck finding one, the space inside doesn’t allow that.
Then, a friend of mine told me about this supplier, Diavia.it, an Italian company dealing with hvac spares now owned by Webasto and found this evap unit on their site http://www.diavia.it/eng_spares.php?categoria=97&sottocategoria=171&marchio=0&id=3211 After measuring inside the heater box and comparing the dimensions specified on their site a new idea came, it seemed possible to throw away the Vanagon fan and make room on the intake side of the heater box in order to accommodate the complete Diavia evap unit. Cooling capacity 4kw(13600 BTU/hour) seemed also good, so I ordered one, it looks like this

The integrated fan has a good flow, 450 m3/h on the spec(I couldn't find the specs for the original Vanagon one for comparison) it has three speeds and built in resistor so it matches exactly Vanagon wiring. Power consumption is lower than specification, I measured 6,5 amps on the 3rd speed. The fan is branded Spal, it's a brand with good reputation on the automotive industry (Spal is also an Italian company)
I started to cut in the fan squirell cage with the main goal of reaching the same height of the original box as the front of the heater sits very close under the windscreen lower crossmember. Also I had to be carefull not to get into the heater core space and not to cut in the upper heater section where air distribution to windscreen and dash are handled. Here are some pictures of the lower section of the box.

The Diavia unit fits very tight inside. I kept the upper part of the squirrel cage to act as a strap to the Diavia unit, and altered a bit its shape with a heat gun to get nicely around the new fan cage. By this the Diavia unit is tightly secured, no risk to slide up, down or sideways into the heater box. I didn’t need to use any bolt or bracket to secure the evap unit to the heater box. Need to mention that the evap unit is fitted upside down because I wanted the hose connections on the right hand side. The condense water drain nipples are now facing upwards and are useless in this new config so I cut and plugged them. Some length and height adjustment were needed on the Diavia box as well but no major complications. Here is some pics with the Diavia unit fitted.

The condense water will now be pouring inside, on the bottom of the heater box, that was the reason I chose a panel van heater box, they(obviously) don't have the passenger vent flaps so the bottom is plain solid. On a normal heater box, the bottom flaps and rod have to be removed and holes plugged, a bit more labor intensive(the flaps are spot welded in three points, those have to be ground off before the rod can slide sideways). To be on the safe side I sealed with silicone around the bottom part of the box inside. For the drainage system, I drilled two side 10mm holes and installed two nipples on the bottom, here are pictures with the schematic and the glued nipples. Not in the pictures, 6mm hose on the box nipples, 8 mm from the T nipple to outside of the van via a hole drilled on the passenger vent duct and another one on the firewall.

On the (now) condense water tray I used this felt for antisplah protection( it is used as dust filter on commercial buildings ac system, they are replaced as part of the annual maintenance program, I got an used one). I used it also on the front air intake to protect the new fans from dust and insects, there is little restriction of air flow and it is easy washable, below some pics. Since is rather thick(~2cm), for the heater bottom install I sliced in two.

In order to finish the air intake to the new fans I bought two 100mm diam 90* ventilation ducts from a hardware store, and shape them to fit on the upper part of the box in order to direct the intake air to the fans, see pics below.They are glued to the box but not to the fans to be able to remove the upper section of the box in case of repairs, heater core replacement, etc. Around the fan the intake is sealed with self adhesive window insulation sponge. Here is a pic with the final cut on the upper heater box and with the intake fitted

The forced air ventilation flaps(approx half of initial size left each side) are glued in position so that all intake air goes through the fans. I thought I would miss the draught air at highway speed and have to use the fan from now on, but I got a nice surprise on testing after install, there is plenty of draught air coming through the Diavia evap unit even at low speed
When testing the fit of the unit I found there was a clearance issue of the right hand side fan with the wiper mechanism, I had to flatten a bit the shape of the fan with the heat gun and shave off a plastic tab, also change a bit the position of expansion valve capillary tube

As the Diavia evap doesn't come with any control devices I installed a 4 Celsius thermostat(non adjustable) for evap icing protection, I bolt it inside the heater box on the left hand side, plenty of room there , and inserted the capillary tube in the evap, few pics below.

Wiring is almost std, the only diff. is that I didn't install an ambient temp sensor, the compressor is cycling together with the 1st stage rad fan via evap thermostat. The compressor is wired via a trinary switch for low/high refrig. pressure protection which also give a signal to 2nd stage rad fan. Each of the three circuits(compressor, 1st stage and 2nd stage rad fan) is protected with relay. Position 5 on the fuse box for 2nd stage relay and use conector H pins(std), 6 for compressor relay and use conector L pins(this is std for dual horns but I know I will never want that option) Compressor has a separate fuse(before trinary switch), rad fan wiring is protected by fuse no.1 on the panel. Evap fan wiring, as said before, matches exactly Vanagon switch wiring. I sealed with silicone the three fan connectors to protect from oxidation as they are exposed now to fresh air

AC switch: as I didn't want to alter the stock look of the dash, I used the lower vent lever(not any longer in use since there are no passenger vent flaps), to actuate a micro-switch fitted inside the dash. It's "on" when I turn the lever to the left. By coincidence, the graphics on the panel for the lower lever show an increase in cold air towards left(blue triangle) Here is a pic with the "no AC switch dash"

I replaced the original rad fan resistor(one speed) with an Eurovan two-speed one, found also a matching connector for it from a Golf mk3 wiring

Hoses, condenser, dryer installation I won't detail here, was covered very well in other posts, just a pic and a few comments on the condenser: 14x22 on the spec, 14x23 out of the box plus another inch on the side fitting frames. Doable but challenging to fit, the good thing is that is sitting tight to the radiator, good air flow through. The performance of it is awesome, hot on the top, barely feeling warm on the bottom

A pic with the finished heater box and the install under dash. It was a bit complicated to fit in position due to the routing of the refrig. hoses, drainage hose, and the clearance of fan and hoses to the wipers mechanism. I left the refrig hoses half a meter longer under the van in order to have room to maneuver the unit on the install or future removal. I had to be careful not to damage the drainage system which after install goes nicely inside the cross ventilation duct.

AC compressor was already on the engine since the tdi conversion 5 yrs ago, it's a Sanden SD7H15
Refrigerant fill: I went by the gauges and an AC chart ending up on 1350g after 5-6 attempts with higher and lower qty. At ambient temp of 26C(77F), low pressure gauge was showing 2,7 bar(~40psi), high pressure gauge 15bar(~220psi). Temp at driver dash vent 6C(43F). Oil qty 240g

Now, it's been three months since I have the unit installed and I drove the van some 2000km at temperatures ranging from 25 to 40 C(77-104F). Firstly, the fan has a better flow in comparison to the stock one(or at least the one I had), noise level is more or less the same. Also, as mention earlier, it allows a good amount of draught air even at low speeds it saves on the fan when driving outside the city. As being a manual AC system, I have to play with the fan speed depending on outside/inside temps and van speed.
Under 30C(86F) it cools the cabin in few min. On this range is more useful for humidity than for heat. After 20 min-half hour I can hear the compressor/rad fan starting to cycle, sometimes every 5 sec even on 3rd fan speed because of the evap thermostat. At this point it also gets quite cold inside and sometimes I switch off the AC.
Between 30-35C(86-95F) the cooling performance is lower in the beginning, the dash vent temp is higher in the first 10-15 min(I didn't measure it's only by the feel) The cab cools in 30-45min and than it maintains pretty good by playing with the fan speed. Compressor cycling doesn’t occur so often, it’s probably every 10-15 min I hear it
Above 35C a cab recirculation option would have been great, it gets longer times to cool down the cab. Even if I keep the fan only on 3rd speed, it doesn’t come to that point were I should feel the need to maintain the temp, especially when closer to 40C outside . What I do is to direct dash vent to my face to have cold air feel, same for the feet, and that works quite good for me. Compressor doesn’t cycle anymore, in city traffic 2nd stage rad fan kicks in and stays there all the time, it only goes out after a 10-15 min driving at higher speeds outside the city
I can’t tell about the temp comfort in the rear passenger area, I had no one yet there to tell
Regarding fast compressor cycling at low outside temps: I suppose the temp exchange is not fast enough after the cab has cooled and when outside temp is lower, the evap is icing. I can't tell such fast cycling is normal or not(I can only guess the thermostat is too sensitive), I found it annoying and solved it by replacing compressor relay with an adjustable delay-off relay (Hella, p/no. 5HE996152131) which I set at 15sec. I checked with the gauges and there is no abnormal drop/increase in pressure and the air flow at the vents is the same. An adjustable evap thermostat might have done the same job, but I can't tell for sure.

Bottom line, I am pretty satisfied with the set-up, especially that I reached my main goals: dash stock look/function, fresh air intake, decent cooling.

The project took me approx two months, over the winter, 1-2 hours/day, but there were days I didn’t touch it. I took my time to think and choose what I thought is the best alternative at every stage, and did everything in incremental steps. I am no AC specialist, just familiar with the basics of it, no in depth knowledge or experience. I was lucky enough to have the spare heater box to work on and a friend van with the dash out for testing the fit, so I could use my van during this time. The final install of the heater/evap unit, hoses, condenser etc.. took two days and I had two friends helping me. Too early now to tell if I would have done things differently had I started all over
Cost: approx. 1100 €, whereof 250 on the Diavia evap unit, 550 on the condenser, hoses and fittings(same system as Eaton EZ clip but different supplier), 100 on a new heater core and 200 on refrig. fill and miscellaneous
Sorry for the length of the post

Cheers // Iulian

[Steve M.]

Julian, very good project and well executed! Thanks for the write-up and details in pictures and all the good stuff. I might be dupilcating your efforts sometime soon!

[iulian]

Thanks Steve, good luck! I would happily help in case you stumble across some details I missed to cover here

[djkeev]

iulian, stunningly impressive!

This post shows how to install what is as close to a "drop in" A/C Evaporator as I've ever seen!

Great job! 👏

If I hadn't already modified my air box to recirculate cabin air, I'd be all over this!

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[Zeitgeist 13]

Absolutely brilliant.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[djkeev]

Though, doing some searching, I cannot seem to find a sales point for the Diavia 62U003FF084EC in North America........

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert