I know most of y'all take A/C out of your 914's but I'm hoping to add it and am wondering if anyone can give a little advice.

I just aquired an old underdash unit manufactured by Heatransfer out of San Antonio, TX. I've read that VPC and DPT made underdash unit and so this might be a little unique...I dunno. At any rate the underdash unit appears to have everything needed such as expansion valve, standard pcar looking blower motor, etc. From the unit runs a red line (12v hot), green (ground), and red (compressor relay). Bench test shows that everything appears to work correctly and I also have picked up the original York compressor and a relay of some sort with the unit but I've no clue how it's to be wired or what. Below is a picture of the connectors and the only info on the relay is 150-10 12V.

Forgive my ignorance here but first does anybody know what the relay pinning is or is it even really necessary to run a relay. From what I can figure I should be able to connect (red) compress relay line direct to the compressor and evaporator fan and I'm guessing the underdash unit would trigger the compressor and evaporator fan to kick in as needed....am I off base here or do I need a go-between relay some where in this picture?

I have access to R12 and evac machine on the cheap and so I may upgrade the compressor down the road based on performance but for right now I'd like to get it all hooked up and see how it runs to begin with.....any advice would be GREATLY appreciated. I am willing to buy a new relay but admittedly I'm clueless on what I would need.

The manual has a wiring diagram that should help.

VPC_Air_Screen.pdf

I'm no expert, but when I installed A/C in my '69 bug I restored, the only relay used was to power up the compresser clutch. I guess it draws some serious power when it is first energized. So, I'd guess that your relay is for the compresser clutch.

Pinout on the relay...sorry. Guessing would be, one pin would be direct 12 volt into the relay from a direct battery connection, one pin would be attached to your temp control to cycle the compressor on / off, other pin would be 12 volt out to the compressor, also a ground somewhere.

YMMV. Good luck

Thanks for the info this cleared up the questions. Plan on running two relays from the underdash unit, one to the compressor clutch and the other to the evap fan.

So does anybody know where to get a throttle solnoid for a carb setup?

jPs,

Here's a link to a previous posting. It includes an A/C wiring diagram I put together that may be of some help.

A/C Link

Best of luck,

3D914,

Thank you VERY much...going to get replace hoses this weekend then I'm gonna give it a try.

Bump on the throttle solnoid if somebody has a source.

I have the DPD system in mine with a few tweeks and have R134a in it.

DO a search here and on the bird board..but here are some of the MUST do's for a conversion to 134a but most aplly to R-12 too:

- Replace the drier
- Get new hoses
- Get a new fan, electric ones are cheap and will help with the vent temps
- Replace the TXV (expansion valve) for the evap. These run about $30
- Flush the system and add NEW oil.
- Pull a deep vacuum for about an hour and charge by weight
- Get a binary switch for the high pressure cut off

I was going to put a WOT switch in but decided against it. Every time you let off the gas the compressor would kick-in feel very funny with the on-off-on-off-on-off.

I installed a nice switch to kill the A/C if I was in need of some extra horses. It only takes a second to flip the switch and it will keep the A/C off untill you pass that dam miata

Best of luck

a little off topic but..

i saw a street/strip bug that had a AC style electronic clutch pulley on his alternator. flip the switch and let a few horses free

back to VPC, DPD,914, AC, etc.

In the relay pic, typically the two terminals to the right of the pic would be the "coil" side of the relay (control), and the other two (double spade and the one up to the left) would be the switched terminals (load). Easy check - but 12V to the coil terminals and you should hear a click as the contacts make and break. A VOM set to ohms can be attached to the switched terminals (as you apply 12V to the coil terminals) to ensure that the contacts are actually good.

I don't think there was ever a provision for throttle solenoid. You could try to adapt something like the photo below. It would be easier to adapt to FI than carbs.

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...TRK%3AMEWA%3AIT

Looks like I've a finalized plan now, just need to go talk with the keeper of the checkbook and order a few extra parts I hadn't thought about such as the expansion valve & binary switch.

Any recommendations of good places to order parts is appreciated....most places I've called around here want more than online shopping + shipping charges. I will checkout pelican and tweeks however.

thanks again all

For those of us longing to get their A/C units updated and re-installed someday please share your project and install with us.

Also, I know these people have some modern compressors and other A/C components that have been used on some 914s here in Arizona and also in Texas so they should have, The Good Stuff™.

http://www.ackits.com/

Great thread jP, send us some pics. Would love to see how it looks when installed (never seen one personally).

PS: Great to hear from another Texican!!

ACKITS.com is a great place to get parts. I'll get the guys e-mail I used and he can get anything you want at great prices.

The binary switch is best to get as part of your NEW drier. If you bought a drier without one no worries they sell a switch that can be installed in-line. The TXV can be bought from the above (that is where I bought mine) for about $30.

How are you going to get new hoses and/or fittings? Some place charge a crazy abount to crimp A/C hoses. You will need to have 2 or 3 fittings crimped onto th enew hose AFTER you feed the hose through the car. Just tape up the end and feed the hose through the dealer installed holes or drill your own.

Don't forget to locate and drill the hole for evap drain pan hose. It's a pain to get the drill to fit under the evap after it is installed

Cheers

Sharing the project seems like a good idea and so here goes. Here's a pic of some of the main componets. Underdash unit, compressor which eventually I'm gonna replace as it weighs about as much as a boat anchor, condensor, and the old dryer.

Forgive the camera but it's an old cheapy.

Here's the original condensor mounting unit + fan and cover. After speaking with my finance manager last night she reminded me things are a little tight so I'm going to use some parts and upgrade later...like this fan. I let it run all night last night and it appears in good shape, except that as it's old I'm sure it draws a heavier current than newer models and displaces less air, but it's gonna have to work for now.

My teener previously had air and the PO had left the condensor and lines in tact but everything else was missing. Here's the trunk area and you can see the cutout area done by the original install. There's some surface rust so I'll be cleaning and painting all this up. I'm also not real satisfied with the air circulation as you can see the cutout areas are kinda silly....I've a few ideas and will be rearranging the layout.

You'll also note the hardline coming up from the bottom and all lines will be replaced. On the top left of the picture you'll note the cutouts for the lines. One was used for the windshield wiper pressure hose to the spare tire and since I'm going to replace that with a electric pump driven system I'll probably make use of that for a/c line routing.

jPs,

Before you cut up the hole(s) in the trunk any more, consider this. Typically when done by the dealers adding the air, a large rectangle was cut out of the floor. This was especially true with VPC system, as its condensor had a bigger footprint.

When I replaced my system, I went with the DPD condenser you have shown - as it has greater air flow than the VPC condenser. My trunk already had the larger rectangle cut out for the VPC unit, so I had to retrofit some pieces to seal it all up.

What I'm getting at is that if I had to cut one from scratch, I would do it much like what you have there, and here's why. If you look at the underside of the condenser housing, you will notice that the front part (about 1/3) of it is for intake air that is drawn up through the condenser fins. It then passes out the back (about 1/3) to vent.

Rather than one big square hole inthe trunk, all one needs are two rectangular hole as you have there - one for the intake & one for the exhaust.

The other ring they left sticking out was the tow hook, but you could remove that if you want - as it doesn't look like there is quite enough material there to do the job.

Also, you may want to get some scrap thin sheet steel (1/16 in) to make a small air scoop for the front intake vent. I'll try to get some pictures of mine. It just helps get more air directed into the intake from under the car.

Just my $0.02

jPs,

The picture of the trunk reminds me that there is usually a forward facing scoop that extends below the trunk floor in the front slot. This was a piece of sheet metal bent at at about a 45 degree attached to the sides and rear edge of the front opening. It apparently helped scoop air into the opening, up and through the fprward portion of the condenser coil.

For the rear opening there was also a sheet metal flap or deflector that was supposed to help the exhaust air discharge. It attached to the front edge of the rear opening and extended down below the floor, also at a 45 degree angle.

How well these aero devices worked under the floor is anybody's guess.

Do you have the pulley that mounts behing the cooling fan?

If you are going to reuse the old hoses I would just connect up what you have for parts. I wouldn't buy anything new and connect it into the old system. Chances are high it will need to be opend back up next spring

You will also probably loose your charge of R-12 over the winter since the old system was designed with bleed typoe hose.

Once you get the $$ ready to do the system right and replace everything listed earlier with new.

The cost of my A/C systems was about $150 for the original A/C system and about another $200 for the retro fit to R134a and new parts. Labor was all done by me that saved some big $$$$ A/C shops get a premium rate for labor.

Cheers

The PO had the engine rebuilt and the pulley was missing. I picked one up from slits here on the board and plan on installing it.

I'm planning on installing all new hose line that's 134 barrier and o'rings. however I'm gonna run r12. I have free access to a friends auto repair shop and he has all the needed equipment to evac, charge, etc and all I'll have to pay for is r12 and oil. He's pretty cool about everything it just has to be done afterhours and I have to do all the work myself. So basically I'll get it all plumbed and ready at my house and then over to his shop for the rest of the work. I still need to checkout pricing on hoses just haven't had time.

BTW: The old hoses were so brittle they cracked when pulling them out. The hardline is pretty much fubar with stuff in the line.

The compressor I picked up, while it weighs alot is in very good shape, the oil was clean and I couldn't find any debris so I'm gonna use it for now. I actually prefer to run r12 as it's superior to 134 (IMHO) and from my perspective the enviromental folks can I actually live in farm country and if you saw the cars around here mine is an epa dream in comparision.

Regarding the venting of the trunk I agree. My rough plan was to cut the tow hook as it's worthless and I will be welding in a scoop but I'll probably use a heavier gauge of metal to stand up to armadillos that are always on the road in the early morning and evenings. No sense in having bent up tin underneath if necessary. I'm also going to install galv. mesh to keep out the rocks. I pulled several 1" rocks out that had found themselves lodged around the condensor.

Keep the ideas coming as it makes one think more before throwing things together plus this thread will probably help someone down the road as I've learned more from this board than any manual can provide just in the past searches I've done.

If you wanted to keep the tow eye you probably could weld a little angle or square tube around the perimeters of the openings and add a some cross bracing at the tow eye panel. You don't do major towing with the tow eye, just a little pull if you get stuck in the mud or snow.

My car came with a non operational VPC system installed. I found a DPD condensor on Ebay & Bought a Sanden rotary compressor. I plan on running R-12 or some kind of R-12 replacement. The A/C shop I talked to recomended against using R-134 because it is less efficient & produces higher high side pressures.

Be careful what you make the flap under the car out of. The factory VPC flap on my car hangs down & is constantly getting bent. Maybe some kind of stiff plastic or rubber would work better.

I like the idea of welding some small square tube around the condensor opening.

The DPD system I have doesn't have the "scoop" and everything works fine. I do have a higher CFM fan so that might be making up the difference.

R-134a will work fine (vent temps in the 40's) in our systems with a few tweeks and can be easily obtained at the FLAPS

I'll have my vent temps into the 30's for next summer I just didn't feel like opening my system up again this year.


Does anyone know who the guys was who was looking for the DPD condenser cover? PLeas ehave him contcat me again

Cheers