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Posted by: tygaboy Aug 1 2019, 05:06 PM

Hi World - I need some info:
I'm working to add A/C to my build and I found this little set up that's 10.5" wide, 8.5" deep and 4.5" tall.

What I don't know is what's possible in terms of orientation of these evaporator/ fan units.

I know they have to drain any condensation (and not into the motor, etc.) but assuming I address that:

- Is there any appreciable impact to how the evap unit performs if it were stood on end, turned upside down, etc.?

Essentially, does refrigerant care about flowing up vs down vs sideways?

- Do any of the other components, like the expansion valve, care about orientation?

If needed, I'm totally OK with cutting up the case, making one that suites my needs and reusing the components.

Or, if there are other considerations, if I'm missing something, please let me know.

Thanks in advance for any help!

Chris



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Posted by: Cairo94507 Aug 1 2019, 05:09 PM

Mmmmmm.....man I wish my Six had AC!

Posted by: jcd914 Aug 1 2019, 05:18 PM

I don't think freon or the expansion valve care about their oreintation.
The squirrel cage fans are designed to have the shaft flat.
The fan life will be shorter if mounted sideways but probably it will last many years.

Jim

Posted by: tygaboy Aug 1 2019, 05:38 PM

Thanks Jim!
I'm still in the "hmmm, maybe it'll fit here" stage but the current plan (assuming things will work with the orientation) is to stand the evap unit up and fit it in the general location of an Appearance Group console. I can build a case that mounts two squirrel cage fans, one above the other, and keeps the shafts horizontal.

Posted by: Chris914n6 Aug 1 2019, 05:48 PM

You can mount it however you want, freon don't care.

The motors will depend on the bearings, but many factory blowers face vertical.

You will need a good drain or it will get stinky.

You can mount it IN the center console if you wanted, it looks small enough. (lol I type slow)

Posted by: tygaboy Aug 1 2019, 05:57 PM

So it's sounding safe to "Go Vertical!", at least for the evap stuff. I can work out the fan situation. I may want to use something different anyway.
Thanks!

Posted by: amfab Aug 1 2019, 07:05 PM

I think orientation makes a difference if it is a parallel flow evaporator

Posted by: FL 000 Aug 1 2019, 07:29 PM

I happen to be researching the same thing right now. Not pushing one brand or another, but checkout the Vintage Air 2019 catalog. Lots of good info that probably applies no matter who you go with. For example they point out that the receiver/drier orientation is critical, since it separates liquid from the gas bubbles, and you want the tube always immersed in the liquid (e.g. vertical). They are also specific about how you mount the condenser. For the eval unit you probably have some more play to modify it, as long as you make sure the condensation can drain.

I will be watching your thread since I am shortly behind you. Heat by this winter, and A/C by next summer is the plan!

Posted by: Rand Aug 1 2019, 07:37 PM

AC is for weenies. Spritzer bottle.
(I know, I know)

Posted by: mepstein Aug 1 2019, 08:15 PM

I’m a weenie. I like heat too.

Posted by: TravisNeff Aug 1 2019, 09:10 PM

One of my past 914's had dealer installed AC. For the condensation drain there was a hole in the firewall behind the dashboard and a hose was passed through and down into the area of the steering rack to drain.

Posted by: Rand Aug 1 2019, 09:14 PM

That's what jackets are for. You have to get outside the car at some point. Dress for the weather not the inside of the car.

Just teasing as you know.

Posted by: 76-914 Aug 1 2019, 09:31 PM

Actually Rand, AC is for comfort Those who walk upright usually approve.

Posted by: djway Aug 1 2019, 10:50 PM

Limited understanding here but I believe the liquid feed is supposed to be below the gas out.

Posted by: Andyrew Aug 2 2019, 03:13 AM

The case should have some kind of drain port you can use to orient it. Apart from that it shouldn't matter how you mount it. The best spot I found is either directly where the wipers are (no go for wipers) or where I'm mounting mine (glove box area cut into the firewall).

You can go all project Binky on us and totally make a custom housing to fit somewhere but it's all about those fans as they are the bulky item.

Posted by: tygaboy Aug 2 2019, 07:44 AM

Thanks Andrew. I've started looking at DC brushless fans to replace the squirrel cage set up. There are some ~ 5" x 5" X 1.5" that appear to have adequate CFM.
Something like this would really open up where I could fit it and might allow me to totally hide it.
I'm pretty sure I can make this work and not have to cut into the front fire wall.

"Film at 11:00" as I futz with all this.

Thanks again!

Posted by: tygaboy Aug 2 2019, 07:47 AM

I know this is true for the condenser and there are rules for the drier mounting, as was pointed out earlier. In the perfect world, I'll be about to keep things oriented "as delivered" but repackage the components.
I think I'll call Vintage Air and see what they have to say.
Thanks!

Posted by: andys Aug 2 2019, 08:56 AM

That blower motor for the squirrel cage is a very common part used on everything from Ford to Nissan. I don't recall the part number, but might be able to dig it up, if you need to know.

Andys

Posted by: dr914@autoatlanta.com Aug 2 2019, 09:09 AM

if a six the new radial compressor mounts on the left front of the engine and the firewall will have to be modified to mount. Ac lines go down the right rocker panel, oil cooler lines (if engine is 2.7 or larger) go down the left rocker panel, the the oil cooler against the front panel, the ac condenser behind it, both with fans so you will not suck hot air from the exit of the oil cooler into the intake of the condenser. The rest is easy

Posted by: jd74914 Aug 2 2019, 09:11 AM

Be careful there. Most axial fans have pretty sketchy fan curve documentation. You need to know not only the air flow (cfm) but also the corresponding head rise. The original fan impellers likely have significantly higher head rise vs. flow curves to push through the heat exchanger. Not saying the swap won't work, but you really need the fan curves for the original and potential replacements before making a decision.


There can be ideal evaporator orientations too; it's very design specific though. Mostly comes down to the size of the tubes. Unlike condensers it's not super critical, just provides a slight efficiency gain (we're talking maybe a few percent here). I'd be more concerned about blower bearings TBH. In stationary blowers like that the thrust bearings are generally pretty wimpy since they're really not designed for load, just to prevent contact between impeller and housing. In an automotive application you would think they would put some more thought into them due to lateral loading, but who knows.

Posted by: tygaboy Aug 2 2019, 01:14 PM

@http://www.914world.com/bbs2/index.php?showuser=1659 - Thanks for the great input! I've been looking at this Orion fan and they do publish the fan curves, as seen here.
Any idea if a couple of these would work?
If you need me, I'll be off learning about static pressure!



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Posted by: jd74914 Aug 2 2019, 01:45 PM

Maybe. Not sure what the actual flow you need is. No idea what kind is on yours-though if you have a part number or some identifiers I'd be happy to take a look and offer some advice.

I just pulled out a spec sheet for a typical automotive-spec centrifugal blower. See how the static pressure vs. flow curve is significantly higher at low flows and has a different shape? That shape is rather important; as is the location your system falls on the curve.

For example, if the system used this blower and runs with 160 cfm air flow (this number is rather important since airflow really is what controls efficiency of the evaporator), the corresponding pressure drop of the system would be known to be 0.6 inWC (water column). To do the same thing with the axial fan you posted would require 5 fans. Or you could run at lower flows with less fans. Its tough to design without information since everything is very coupled. Likely Vintage Air uses those centrifugal blowers because the pressure curve has a lot of margin (until it hits the knee point) so they're less sensitive to long piping, lots of bends, etc. in terms of overall performance because the blower speed can always be turned down or they can have an overall governing pressure drop.

Posted by: jd74914 Aug 2 2019, 01:57 PM

Hopefully something there made sense or is useful. Unfortunately, a lot of engineering or trial and error goes into fan-based heat exchanger systems. I've worked on industrial systems on and off for the past dozen years, and automotive systems make me uncomfortable because there isn't much data in the public domain for cars. You really just have to guess sometimes, especially when it comes down to modifying aftermarket parts.

Posted by: 914_teener Aug 2 2019, 02:36 PM

Not only that but you have to make assumptions on radiant heat gain. In a 914 during the summer with no insulation behind you the heat gain assumptions become large.


Honestly, you are better off with an ice chest in the seat next to you and one of those directional fans blowing across the top of the ice at your body.

I admire your enthusiasm, and you most likely will learn a lot.

Posted by: white1975 Aug 2 2019, 02:45 PM

small made for classic mini japan

Posted by: Andyrew Aug 2 2019, 02:47 PM

I tried some computer fans like that. Didnt blow nearly any air. A remote mount centrifugal fan might be the best. I have a bilge fan I considered using but after some more trial I ended up just cutting everything out and mounting the whole universal unit. Or at least I wanted to make sure I had room for that when designing the dash.

Posted by: Andyrew Aug 2 2019, 02:48 PM

Whats that from?

Posted by: tygaboy Aug 2 2019, 03:25 PM

OK, so it seems the safest thing is to use squirrel cage fans. I think I'll fab up a case and orient everything to get the package more "914 shaped" while keeping the fan shafts horizontal.

Oh boy, more fab work!

Posted by: Marv's3.6six Aug 2 2019, 03:30 PM

I added a one off fresh air fan and are very happy with the results

To the right of my steering wheel is a ford f150 3" dash vent, behind that vent is a small bilge fan pulling air from under the dash board.... Believe it or not with that air directed straight at my face my car is bearable in most cases during the summer. The whole setup was cheap and only added about 3 lbs of weight to the car. The ashtray was removed for this add on.


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Posted by: Steve Aug 2 2019, 08:34 PM

I bought the same evaporator and was going to do the same thing. The company I bought it from said to mount it at angle so the drain would work. You could easily make a center console to mount it in. I have a six and bought a Benling 12v compressor, so everything but the evaporator will be in the front trunk. Life keeps getting in the way, so this will be a winter project

Posted by: Rand Aug 3 2019, 05:38 PM

I only teased. But I've used spritzer spray bottles to keep the extra AC junk off my minimalist cars and loved every minute of those experiences. I get the creature comfort mode. But I also really love jumping in the old beast with zero and finding other ways around it. It's part of the experience. 914s should not have all that. I have a Honda if I need to be practical.