1971 VW Type 3 Squareback: Air Conditioning Build

[rushtonmd]

Hello Samba!

I reached a milestone in the A/C build for my 1971 Squareback and wanted to throw together a build thread for those of you wanting to do the same.

First off I'd like to say thanks to Frank over at https://www.gilmore-enterprises.net/. We had spoke on the phone and email and after a little bit it was clear that the Type 3 kit he sells wouldn't work for a '71. I have fuel injection, so the compressor brackets wouldn't work. The dash is different on the late models so the under-dash evaporator wouldn't work, and where the lines would run would all be different so at that point, it wasn't much of a kit, haha. I did however end up purchasing the compressor pulley which is working great.

I also want to thank @trythis (https://www.thesamba.com/vw/forum/viewtopic.php?t=664462) for chatting with me on private message and giving me ideas from his build, specifically the drivers side mounted compressor.

Ok, here we go!!

OVERVIEW

So, it's hot in San Diego, and I have 2 little kiddos that I daily drive around. I initially wanted to see about getting popout windows installed to beat the abysmal air flow inside the car. After a little research and talking with a local shop, it appeared that it would be a huge job and my guess is that they'd always leak. So, I moved on to an A/C project.

I have a buddy in Kansas City who has been in HVAC for the last 25 years or so and was able to walk me through the basics of A/C - I admit, I knew nothing and now only know slightly more. I did a ton of research on hot rod and VW A/C systems.

There were a few ideas I wanted to anchor to. First, I wanted a system that would keep me and my 2 kiddos cool enough to daily drive in San Diego. Many back of the napkin calculations for compressors puts you around 8,000-12,000 BTUs for many Hot Rod systems, which by everyone's accounts would only just knock the edge off and not be sufficient. The squareback has a lot of interior volume to cool. Using just compressor data, many/most production car systems fall within the 18-24,000BTU range. This was my target.

Next, I wanted to keep the look of the interior as clean as possible, and anything added should compliment or look like a refresh of the old system. I'm not a huge fan of accessories and gauges and doohickeys all over the interior. With that, I also never really into the aesthetics of the under-dash systems. They are about as stock as you can get, but they take up a lot of visual real estate, screw up where the radio goes, and are just big and bulky. I wanted it to be as stealth as possible.

Lastly I wanted a system to be as robust as possible. I need the A/C system to not be a huge burden on the 50hp motor, be clean and clear of obstructions, and be well balanced enough to cool the kiddos and last for the next 10 years without tinkering.

Compressor Bracket

I knew I wanted to keep the motor as stock as possible. Being fuel injected meant that the oil-bath air cleaner was right in the way of most brackets for the A/C system. There was plenty of room on the drivers side for a compressor. My idea was to create a cradle for the compressor and the alternator out of a single bracket. I ended up going with 6061 Aluminum for the entire thing. I don't have a welder, but it's easy to fabricate up and a local shop did all the final welds for me.

I wanted to get the compressor as big as possible to fit the space and be a good balance for the system. I ended up going with a Sanden SD7H13 compressor with the rear-exit ports. It's a good balance of physical size and output.

I definitely have some work to do on the fan shroud... coming soon!

Evaporator Box

I wanted to keep the interior clean and stock looking as possible. I immediately jettisoned the fresh air box under the dash. Mine was not working (the motor was shorted out), and from all I've read, they're pretty terrible anyway. I tried to find a way to reuse the box or fan or anything, but to no avail. In the end, it had to be removed.

I tried to see if the Hurricane A/C would fit under the dash in its place. I purchased a mock up box and it turns out it was just too big to fit, but I was able to cut-apart some of the box for my final install.

https://www.oldairproducts.com/products/ac-systems...onic[/url]

Here's a mock up of a blower fan and the Hurricane box that ended up not working at all.

Just too big.

I knew at this point I needed to build a custom box. However, getting it to fit under the dash was a no-go to get the size I wanted out of the system. I figured that the front trunk gets almost no use and is just wasted space, why not put the A/C system up there?

I ended up going with an evaporator core out of a Mazda 626. The core is a good size for the install, and comes with easy attachable o-ring fittings (albeit metric). The evaporators and fans need to matched as well as possible, so I purchased an air box with fan out of a wrecked Mazda 626, and chopped it up to build the new air box. By doing this, the blower, expansion valve, and evaporator core are easily accessible (and cheap!) and I know that they are all balanced.

The evaporator box pulls air from inside the car and blows it back into the interior by cutting 2 holes into the firewall. I reinforced the wall with an 1/8" sheet of 6061 aluminum all bolted to the box with rivet nuts. It turned out really stout.

Condenser

The condenser was probably the easiest part. I removed the spare tire and spare tire sheet metal hump and bolted it in. I have 2 cooling fans wired up to a trinary switch.

A/C Lines

I wanted to keep the install as clean as possible, so I used rigid lines under the car and instead of grommets, I used firewall transitions. I was worried that this wold add a bunch of extra places for refrigerant to leak out, but it turned out great and didn't leak. I rattle-canned the rigid lines black and you can't even really see them under the car. All the connections are standard 6an/8an/10an o-ring fittings.

I covered all the wiring with PVC sleeving and grommets for a stock look.

Interior

One main goal was to use the original vents in the dash (along with a few more if needed). I was able to build an outlet adapter with some y-connectors to hook up the original vents in the dash as well as 2 additional ones next to the radio.

Since removing the fresh air box, I had 2 holes in the dash that were perfect for a blower motor and A/C switch. The A/C switch is nice when I need to, you know, go up hills, haha.

Charging and Rattle Can

After charging the system and monitoring superheat and subcooling (I had no idea what any of that meant a few weeks ago) it turned out that the system wasn't really working as designed. Again with my buddy's help, we tracked down that the expansion valve I selected wasn't working well, it was sized too small. I purchased it for one of those Hurricane systems, which it turns out puts out way less BTUs than the system I was working on. I was going to get a custom expansion valve made (which I wasn't happy about), but I went to the local auto parts store and found a 1.5ton (approx. 18,000 BTU) expansion valve for a 2002 Ford Explorer and hooked it up to prove the concept. It worked like a charm, and for only $18.

I still have a bunch of small things I'd like to do, but masking off and rattle canning the entire trunk was an easy way to get everything looking presentable.

My highly calibrated 2000 RPM charging board.

Final Product

All in all it turned out really well, I learned a bunch and am getting 40 degree air out of the vents which isn't too bad! I'm ready to see how well it holds up in the hot California summer.

I had tons of help from the community, so feel free to reach out with any questions or ideas or feedback or suggestions.

[Bobnotch]

Nice install and pics. I have a question though. What did you do about the big hole for the original fresh air box? Just asking as you outside in front of the windshield vents are still in place, you'll get water into the car from them. And plating off the former fresh air hole doesn't quite drain enough, you'd need to do something there (or have some rust form in that area).
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Bob 65 Notch S with Sunroof
71 Notch ...aka Krunchy; build pics here;
http://www.thesamba.com/vw/forum/viewtopic.php?t=249390 -been busy working
64 T-34 Ghia...aka Wolfie, under construction... http://www.thesamba.com/vw/forum/viewtopic.php?t=412120

[rushtonmd]

[Mike Fisher]

My popouts don't leak a drop. Bobnotch used a Bug hinge to make the installation easier.
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69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold

Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey

[Bobnotch]