Hi, I am in the process to install an original 914 VPC system in my 914-6.
Like all my projects, I work on a budget.
First I bought all the parts about 5 years ago, then I refurbished all parts, (professional cleaning, expansion valve) installed the condenser in the front trunk as designed, temporary installed the evaporator console under the dash, and start the preparation process for the compressor installation.
I want the installation to be as close as possible to a factory one.
For me, is not an option a compressor under the engine, a serpentine belt or similar. I prefer to work extra time, and reach a perfect end product.
I used a double pulley from a 74 911, in order to install the pulley and have space for the dual belts, I have to shave a bit the original engine support and the engine cover (see photo).
I fit a 2.2 or 2.4 bracket. So far no problems, the end result looks very nice
Now I need to choose the compressor.
The York is out of question, due to size and efficiency. My options are a Sanden, a Denso or a Panasonic. Any one fitted with a one groove pulley
Not being familiar with the air conditioner compressors, and the way you need to calculate cooling capacity vs cabin volume, I would like to ask help form all of you.
1. Which compressor will suit my needs the best?
2. Which compressor is the smallest one?
3. The best compromise?
I will keep all of you posted of the progress on the installation and the need or not of a firewall modification.
Thanks
Francisco

I thought it did not get hot enough in France to need AC?!! It got to 106 F. here on Saturday! Drove the teener early then parked it rest of the day. Nice looking teener!

George Hussey at Auto Atlanta has Peter Greg's 916 that I think has factory installed AC . The pulley of the AC compressor must go through the firewall. On George's car there is a hump in the firewall behind the drivers seat.

I'm pretty sure George's 916 has a crude, covered up hole in the firewall. I also remember reading it was not factory installed but added on when the car was brought over from Germany. There is no "factory" installed a/c in a 914-6 and so far, very limited success with aftermarket installs. The factory a/c mount on the six causes the compressor to hit the firewall.

I wonder if an electric compressor might work. Like something used on an electric car.

Hopefully Clay Perrine will chime in here. He's done a very clean install on a 6 conversion using a serpentine belt set up.

It did look good but didn't work in the long run. I think the compressor bracket was bolted on to the valve cover and broke the studs or something. I am hoping he comes up with a solution.

Hello,


talk to michale at mittelmotor, they have just done AC in a 6 for some guy

Roman

I used a Sanden 505 compressor because it was the smallest unit I could find at the time I was looking, although I didn't look at the Nipondensos. Here's the way I solved the firewall interference problem:

Click to view attachment

Click to view attachment

As you can see, I used a jackshaft to offset the belt drive toward the rear enough to clear the compressor, which had to be mounted as high as in the stock location. The Sanden 505 is short enough that there is room to do this. The clearance in the car is tight, but the compressor clears the firewall without requiring the latter to be cut:

Click to view attachment

I've seen several other 914-6 AC installations that use some sort of jackshaft arrangement similar to this one.

I too considered an electric compressor, which would be attractive because it could be mounted almost anywhere. The one in the Prius (at least the one in the early Prius) ran on 12V even, but it draws 100A! That's a lot more than the maximum output of my alternator, so you'd be discharging the battery steadily when running the AC.

I actually solved the AC bracket problem. When I built mine, I used the serpentine belt, and made the compressor bracket mount to the smog pump mounts on the timing cover. That caused too much load and the timing chain box cracked. My plans are to extend the bracket to the engine mount, and use aluminum to build the bracket to lighten it.

Here is the picture of the compressor mount.



The bracket in the front of the picture needs to be extended to the motor mount.

More info HERE

Is the other accessory drive PS or an air pump ?
How effective is your AC installation ? Are you using other components as found in 4 cyl. installations ?

I don't think the layshaft arrangement would work with a carbed car. Clay's solution may be best once a bracket that attaches to the motormount is perfected.

I always wondered if there would be a way to drive the compressor from a CV joint on the axle. It obviously would only work with the car moving, but may be a viable alternative.

I think that the -6 just wasn't engineered to have AC!

The other accessory drive on my engine is for power steering. The pump mounts where the smog pump used to, like Clay Perrine's compressor mount, only the pump is much lighter than an AC compressor and not hung out as far as Clay had his.

I don't have my whole system running just yet, but no, I'm not going to use any of the usual 914 AC components. I'm using a condenser coil from a Honda Civic and making a custom evaporator using a 911 coil that replaces the stock air box. I'll post the result when (and if) I get it all finished.

Not sure about GeorgeRud's point, since my engine has the stock CIS FI. There is room to hang the compressor out farther to the side than I have it, and If you go far enough with that you can lower it enough that my solution sort of turns into Clay's.

Thats a good idea! I had an idea in high school that you could do the same thing with a turbo, using the exhaust gases to run a compressor. At least it wouldn't pull HP from the engine, but getting it to spin slowly enough and not burn out the compressor bearings. Wish I had been an engineer.

How do hybrids like the Prius run their AC? Must be some sort of electric compressor, otherwise you wouldn't have AC when the gas engine is off. Could one be sourced from a junkyard?

Hi,
thanks to all of you that share your ideas with me.
I follow Vectror advice, and got in touch with Michael at Mittelmotor in Germany.
Michael and his team successfully installed a Cool VPC system from a 914-4 into a 914-6, without any modification at firewall level.
Michael sent me some photos of the compressor, and the bracket they build.
Now I will buy the same compressor Michael and his team used and keep all of you posted with as many photos as possible. Hopping my experience will help other owners wishing to ride cool.
Again thanks
Francisco

On running an axle pulley as a power take-off. It's been used on various cars to power the alternators and I don't see any reason it can't be used on the AC as well. I was going to use it that way except that it would have taken up trunk space. The rear trunk space is all I have left in my 914 so I give it up reluctantly. But to make that work...

I would want to design an electric cutoff to disengage the clutch below a certain rpm (to keep flow through the the expansion valve from getting too low) and that would depend on the relative pulley sizes. The only way to keep it running while below that rpm would be a fairly large electric motor and a differential clutch/pulley. That's a lot of weight for a light car, not to mention the complexity, and there's a maintenance cost for the latter that I'm not willing to pay.

I haven't jumped in on this but may next year since I have most of the bits. Too many projects to worry about it this summer. Hmmm

Ice/water box and a small electric pump for a cool-jacket, or an RV / AC box on the roof!?

Wouldn't that be a sight...

Typical Arkansas redneck way of fixin stuff...

Use lots of duct tape.

And keep an eye on your steering wheel.

Hey! Don't start with me dude! I know exactly where my steering wheel is and as long as you and JT aren't around I generally do, with a very few senior moments notwithstanding. And I didn't date any cousins... mostly... that I know of.

The axle-powered compressor would work fine most of the time but I would never do it to a city-bound car. There are no critical failure modes I can think of with one exception. Changing belts would be an itch.

Does anyone have any numbers about how much power it takes to run some typical compressors at speed and 85F or some other milestone? To be fair I haven't looked into it yet. Just being lazy.

I know, it depends but a broad stroke is ok here. I'm thinking a system in good condition would probably such up 15-20 hp or thereabouts but that's a wag without doing any calculations. Anyone? All of my best AC contacts are commercial HVAC guys who's compressors are always run at a constant speed and with different refrigerants. My steam tables are old!!!!

I'm not factoring in any clutch-type LSD issues here. Gotta keep it general-case at first.

As I mentioned I got in contact with Michael at Mittelmotor in Germany http://www.mittelmotor.de they made an instalation of a VPC Cool A/C into a 914-6.
No modification was made to the firewall.
Look at the photos.Click to view attachment

Mikael used a DELPHI SP10 compressor.

Look at the modification on the engine support and front engine plate.
Thanks to Mittelmotor for the help.

Next week I will start my instalation, will keep you posted.

Francisco

Glad to be of service, I have some picture of the completecar, it was pretty stunning...

Has anybody researched electric compressors? That would probably require a bigger alternator.

Would like to follow up on the Mittelmotor bracket and compressed setup. I do not find it on the website (unless it is on the German side)?

Just purchased a very nice 914-6 conversion and want to put AC in it. Did you guys build your own from the pictures?

It already has the condenser (vpc square one) already mounted.

Saw a picture in the restoration guide where the factory did AC and a front cooler together in a 916. Going to do that but will need to reinforce the front truck floor and the oil cooler mount and shroud will be custom.

Anyone done this also?

That Mittlemotor set up looks first class. The brackets look excellent and simple. Would be very cool to know you could purchase this kind of set up off the shelf.

Correct, Brumos installed it, Phil happened to be at the dealership the day they were cutting the 916

I understand no factory AC only dealer installs and for sure the 914-6 has no good AC systems historically.

Want to know if the Mittlemotor setup is holding up long term. Wondering about load on studs, etc where the brackets mount. The brackets look very well thought out and with no interference with firewall I am very interested.

The rest of the system is doable and the new compressors do not rob much power. I will go this route if they are holding up ok

Anyone that has this setup have feedback on it?

Why can't we go with one of the small-ish electric AC units they stash in old American hot rods? I would love to have AC in my Six as it get hot as heck in the summers in the Bay Area where I live.

As the cabin is fairly small in a 914, the interior portion of an AC system isn't much of a concern. The Retrofit units should work, and I believe one of the vendors does have a 914 kit available.

The biggest concern is a 914-6 is turning the compressor from the engine without having to cut up the firewall. A few different set-ups are out there, and I think a lot of people would like to know people's experiences with them.

I'd also love to have AC in my car, and would certainly drive it more often in the summer when it's just too hot! I did drive my 914-6 to the Parade this year with the top off, and after 6 hours in the sun, I was pretty well done for the day!

Would love to hear updates from those working on these systems...

I toy with the idea from time to time. Not really needed here in the Bay Area, but might be fun to have to really increase usability...

I just saw the McMark installed A/C in a 914-3.2 at Hershey. Owner said it worked well and it looked like a clean install. I thought Mark was going to make kits but then changed his mind.

We've (the shop I work at part time) installed a couple Classic retrofit electric a/c kits in 911's. I've talked to the owner about a 914-6 kit and they have a 914 in the shop to work from. It would work great in a 914 but I think it's low on the priority list for the company. He also has an uprated alternator to retrofit in engines smaller than 3.2 to handle the current needed for the electric compressor. It's $900 and his a/c kits are $4K so it's not for the faint of wallet.

At some point, if the 914 version isn't made, I will buy the 911 version and modify an airbox to work. Call me a wimp but once the heat and humidity get above xxx, I don't want to be in a non-a/c car.

I would really love AC in my Six.....I just don't see it ever being made so it will never happen. Where we live it gets over 100 in the summer so having A/C would be a dream.

^ Very interesting. Would love to see more of Mark's setup...curious why he abandoned the project, but suspect complexity or similar was a reason?

Truth is, weather is too often the determinant in whether I take my 914 out...and the car is pretty nice with the roof on and windows up. Will be adding Stoddard heater boxes at some point to get heat again, but the thought of A/C means long trips and summer use would be a lot more attractive. Would be curious about weight and complexity. Porsche got it down to 35~ pounds in the 987, but I am guessing that is a pipe dream in this case!




When you get your car up and running, we gotta grab lunch. We think very, very similarly. And I sure am digging your current build...

The electric a/c is 30lbs. I've talked to the owner about install and he suggested mounting the compressor under the trunk above the right axle and the condenser in the right rear fender, opposite the oil tank. So unlike a regular a/c install, much of the electric unit is hidden and pretty low in the car. The only sticking point is the custom blower box. I would have to fab one that would fit the 914 and then stuff the insides from the electric 911 unit into the box.

A/C is one of the main reasons I'm doing a Suby swap on another car. It's already hacked up from a previous h20 conversion so adding a/c won't really change much. I just want it to be a driver. Summer, rain, road salt, whatever.

^ Does this system also do heat? Cost for the parts? 30lbs mounted as you suggest would be pretty great, even if you have to add pounds for lines and the airbox mods.

Given the price of Stoddard heater boxes, or other alternatives, this may become pretty interesting...particularly if it's robust. Would be awesome to keep the weight low, to be able to stick with headers, and to have A/C without seeing it when you pop the lid, too...

Would be tempting to offset the 30lbs with a lightweight battery, but I've had several friends suggest against that with a carbureted flat six. Will say my car starts right up after sitting, but hot starts can be tricky.

30# is all inclusive. It's really a nice system. Heat is supposed to be next on the menu since they have an alternator capable of putting out the required current. It's used on electric cars now and our cars have very little cabin volume. Right now the complete a/c system is almost $5K if you include the alternator. All the 911's we've installed into are $100K + cars so the cost ration is different than your average 914-6 conversion.

I think you want to keep a pretty good size battery in the car if you are using electric a/c. But I'm certainly no expert.

But I don't like being uncomfortable in my car so adding 2-3 months to the driving season is a huge bonus to me.

$5k~ is no small cost...but...last I priced heat exchangers they were, what, $2500-3000 and you still need other stuff. And don't have A/C, which would be wonderful in a 914. An extra $2500-3000 for both would be a no-brainer in my view. Might have to save up, but just became a LOT less interested in spending the money on heat exchangers. Thanks of the info!

The electric heat is supposed to be in the works but isn't yet for sale. Good heat exchangers aren't cheap but they are at least a bolt on item. The electric heat is a full install job. Nice but a project for sure. If you want heat, I would buy Rick's set for $300, ask him to send them to Ben, Pay Ben the $6-800 to fix (just guessing). Run them until you don't need them and then sell for $1K down the road.

If you end up doing this, I'll send you some restored flapper boxes for a back issue of your mag.

I bought an electric compressor for under $1000. https://benling.coowor.com/shop/product-det...09087VFAMP1.htm That and a small evaporator in the console and I’m good to go. I already installed an aftermarket condenser behind the GT cooler. I installed two PMS louvered panels below the condenser and GT oil cooler shroud.
Click to view attachment
Except for the evaporator all the parts will be in the front trunk. No hoses to the rear of the car.

I bought all the parts last year, but rustoration and repaint has pushed this project out for awhile.

I already have heat via Ben's 1 5/8" heat exchangers.

This is the ultimate AC compressor install....at least for me.
Not my idea but very clever, very clean, well executed and ideal for our 6cyl. engine
compartments.
Carburated and individual intake stacks only.
Motronic, MFI, early alum. blocks, CIS need not apply.
Driven off an extended Alt/fan shaft with a bearing supporting the extension.
I don't know how the shaft was attached at the rear of the alternator.
All I have is this pic.
I do have a 'novel' idea for condenser location.

@Steve Give me a holler when you get ready to plumb that AC system Steve. We can do it in a day if your willing to drive out here.

Well I sure would like to see what our doing. If I could do electric a/c for a third of the premade kit price, I'm in.

+1

Stoddard or Ben HEs plus this could be pretty interesting, and adding the weight low at the front might be more appealing than adding more weight at the rear of the car. Have to think on that some, but short line runs is VERY appealing.

Exciting to see new thinking applied to this idea, and the photo of the alternator-driven compressor is pretty nifty, too...

@76-914 I will definitely take you up on that offer!! After the WCR, I will be working on this project.

I wonder how many reading this will get understand the value of your statement, Mark? 4-5K for AC! Unless you have a "rare 914" that money won't be coming back. That's about the cost to convert to a nice 2.5 or 3.0 Subie which would come equipped with a rotary compressor. I'm not suggesting anyone yank out the old air sucker and do an H20 conversion just for the pleasure of having AC. Just pointing out that these cars weren't designed with AC in mind. That being said, yes you can add AC to a go-cart if you want but how much are you willing to spend in time and/or $$$. I hadn't planned on AC when I did my conversion but the compressor was part of the Subie package and that made AC an easy option, for me, to implement. As mentioned above, these cars weren't designed for AC so the insulation sucks. On a hot day I turn it on "Full Cold" until the interior is cooled down. Within 10 mins I lower the temp to it's warmest setting as the cabin is so small.

^ There is this logic, of course. It's hard to fault, and a good foil to this conversation. Should be weighed by anyone thinking about adding A/C to a 914.

On the other hand, "not on hot days" or "not in this heat" is a subconscious thought that has passed through my head (probably more often than I'd like to admit) since being spoiled by my first car with working A/C, an Xerati. Much later, a 986 really made the 914 a tough sell in summer heat. My 911 SC with a black interior A/C delete was just plain awful as a daily, and didn't stick around long. It was faster than my 914 (in a straight line, anyway), but offered little else in terms of upgrades other than power windows. Felt no newer, really, and no more useable. Sold it and bought my first new car, a 2003 WRX.

Living in the Bay Area, I'd have to think long and hard about the value of A/C vs its cost, weight, and complexity in a car I cherish for its simplicity. But what is the price of owning something you're less likely to use as often? The price of the memories you skipped making, consciously or subconsciously? Lately, my 914 has been driving so well that I've come to realize that I'm not sure if I need a modern Porsche...and what part of my enjoyment in a modern Porsche boils down to a power window on the passenger side and...A/C. Yes, they do everything better, but…a well-sorted 914 is a magical thing.

How much more would I weigh all of the above if I lived in a place where a significant portion of the driving season was hot and/or humid? Would I pay $5k to increase my time in the car each season, maybe thinking of it at $1k per season over five years? Hmm...

And if A/C can be added for $1-2k?

PO cut out the entire engine shelf, trunk bulkhead and installed a crap roll cage. I cut out the rollcage and Amerson is going to weld back in the trunk bulkhead but this car is so far from original that I don't have to care about extra hoses or a pretty engine bay. But I'm hoping for a "no excuses" car, i.e. drive it to the supermarket in the rain, enjoy it when the "nice" cars are in bed, kind of car. But I agree, working with an engine that's already set up for a/c should be a lot easier.

I think you're applying logic to a fundamentally emotional decision, here... While you do have a point, this is a situation where that point very often doesn't matter. If we all made rational car-buying decisions we likely wouldn't have sports cars in the first place.

--DD

VPC A/C unit adapted to 914-6...38 degrees at the vent and worth every $$$, and time spent on the install!

Click to view attachment Click to view attachment Click to view attachment

@swalshaw Are you using the VPC dash unit?

And any more pictures of the mount? Was it sourced from a kit?

Example Classic Auto Air sells a kit for early 1969-1989 LHD 911s