Help identify what brand AC I have and how it should work

[steven c]

My car is an Euro 81 911SC and it was not optioned from the factory with AC. So somewhere along the way it got it. The blower motor and housing for it says SPAL on them and under the dash the air plenum doesn't look like pics I have seen on the forum of other cars with factory air?












The reason for this question is that little to no air from this system is getting to the factory center dash vent or the side vents, it's all coming out of the two holes above the passenger and drivers feet, which is basically useless. Rather than ripping this out I'm considering adding ducts to it and installing Griffiths extra vents even though they are not my favorite idea as they in my opinion do not go with the car. And I'm having a hard time finding a flanged duct connector smaller than 3". Anyone have one of these to help it make sense to me or any other ways to make this work better?? There is no bow tie vent in this system either??

Thanks

[GH85Carrera]

Those are your heater vents under the dash. AC only came out the center vents, and a bow-tie in the center of the firewall. I did not see the bow tie in your photos.

[EC900]

Yep, those are lower footwell heat vents.
The fan has 3 speeds (slider top row, left side) and a combination of two other sliders control where the warm air goes…up or down, dash vents or defrost. There’s plenty of diagrams for the arcane hvac system on how to position those sliders for optimum performance (Ha!) but the fan may be kaput as they always do and if doesn’t screech won’t switch on to high or cable flaps are loose/disconnected.
The center two vents blow fresh air only, no heat unless plumbing was retrofitted.
Compressor still in the car? Condenser in back or trunk belly?
What’s in the smugglers box?
Dealer installed AC, then there’s an under dash air distribution console unit that extends all across, also there’s cut giant 10”x12” hole in passenger foot well and a 4” oval in the center bulkhead which I don’t see in your last photo.

[steven c]

Thanks guys. Both fresh air and AC fans work. The only outlets from the air box are the 2 heater outlet holes as you are describing them. The SPAL fan creates a lot of air but there is no place for it to go. The compressor is there and the system runs fine. My mechanic has it for a clutch and he is also going to look for freon leaks and fix them, it is low. Has 2 condensers, one left rear quarter with a fan(Griffiths?) and the deck lid which we are putting a fan on also.

So, I need to rout the air to some vents and then if needed I will block off partially the heat outlets. The Griffiths instructions for his vent hook ups are worthless as this car has none of the hoses or bow tie vents he is describing. The way it is now it is worthless for AC and I've got to fix it......

Thanks

[steven c]

Bump, anyone modified one of these air boxes for effective AC?

[brianlay]

We need some pictures of the evaporator and the hoses in the front trunk behind the dash.

[EC900]

StevenC:
CCCool VPC and Behr fans were used with most dealer installed AC’s. SPAL is aftermarket fan but not sure about which aftermarket AC supplied them. Take a photo of the entire dash area and post, it may offer clues to the brand of ac. BTW…What’s in the smugglers box?

Your under dash plenum box has to have an intake or two to distribute cold air. Under dash plenum(distribution box) is indicative of a Dealer installed AC and would have one 4” oval cut out in the center of the metal bulkhead (your last photo shows no cutout) and a large 12x10 cutout passenger floorboard for the evaporator (in smugglers box).

Read over this Post, check the setup, maybe the ducting is loose, flappers aren’t operating due to loose cables or parts missing. It also give detail where air should flow and from which vents.

Retrofitting non-A/C ventilation ducts

[steven c]

Thanks guys. I did see that thread you linked as I've read a bunch of them but I'm not getting it. Here is a pic of the smugglers box evaporator, the cars at the shop so all I have for now. The only unique thing about the evap box and fan is that it's too tall for the metal factory lid to close completely?


All of the return air to the evap coil goes thru the small opening at the bottom of the bulkhead at the floorboard in front of the shifter. Since the fan puts a lot of air out the volume returning thru that small opening is moving pretty fast! With the AC fan on and the outside air louver closed no air comes from the 2 side dash vents and very little from the center vent which leads me to think that the 2 systems are pretty close to independent of each other. I can get a pic of the outside air system in the frunk when I get the car back.

I did just find the flange duct pieces I will need to run to Griffiths under dash vents if I end up not finding a better way? They are in England unfortunately buy shipping isn't that bad and they have other sizes. https://www.carbuilder.com/us/2-hole-40mm-od-ducting-flange

So I made a little progress on parts......maybe? Thanks

[brianlay]

We need to see the smugglers box, not the master cylinder and brake booster
Also remove that cover to show the fresh air ducts

[EC900]

Remember the 911 AC is not the best.

Behind that HVAC fiberboard panel - you’ll need to inspect the paper hoses from the distribution boxes on both sides. These tend to crush, crack and disintegrate. I don’t know anything about the install of the system but some require removal and redirecting the plumbing behind that protector panel.

It seems your evaporator intake may not be large enough, but I didn’t see an opening or how warm air is drawn in.
Smoke test the direction of air flow to see if flaps are open/closed and operate directing air high /low to make sure no obstructions or loose connections.
Both fans should have 3 speeds.

As for smuggler box lid not closing, the fitting are in the, maybe.it was easier that way to access and install them, just a bad installation, if dryer is in wheel well, the hoses and connections should have been pre-installed…someone skipped a step and installed the evaporator after the hoses.
When I had AC my lid was somewhat like that too, the little metal closet tab was bent up to keep lid closed and very tight.

[steven c]

EC900, thanks for the ideas. I have had the cover off of the outside air distribution stuff and it is like new. I didn't mention this but the car only has 47k miles from one owner. That's the good side, the bad is not so good mechanics worked on it from time to time. Like the AC install...

I agree that the return air is restricted. The fact that the smugglers box lid will not close completely is letting outside air fill the void which is fine at 80 degrees but not so good at 100 degrees. The dryer is in the LF wheel well and I think you're right, this is a poor install. Pulling the evap box out is a winter project for sure. I will get pics in a few weeks and post them once the car is back from getting a clutch. Thanks again.

[steven c]

Okay, have the car back...but not the engine. Clutch turned into broken head studs so project creep has turned into an avalanche. Oh well. Here are pics of the front system. Let me know if there is more I need to take pics of. Thanks for any help!

[brianlay]

It's definitely not factory, but more likely a dealer installed system. It appears period correct.

The biggest issue, which you've already identified, is it's blowing AC air into the existing fresh air system, on the output side of the fresh air blower.

That means you should be able to steer it either to the footwell outlets or up to the windshield/defrost outlets. Some middle setting will probably give the most flow. And you might want to close the fresh air feed by moving the fan lever all the way left. This will might limit blowing AC air back into the fresh air box.

What you might do is instead connect it to the dashboard outlets, but prior to 1986 those are not very large.

Figuring out a way to feed into all outlets would be the best but that will need some fabrication of ductwork.

[steven c]

Originally Posted by brianlay

It's definitely not factory, but more likely a dealer installed system. It appears period correct.

The biggest issue, which you've already identified, is it's blowing AC air into the existing fresh air system, on the output side of the fresh air blower.

That means you should be able to steer it either to the footwell outlets or up to the windshield/defrost outlets. Some middle setting will probably give the most flow. And you might want to close the fresh air feed by moving the fan lever all the way left. This will might limit blowing AC air back into the fresh air box.

What you might do is instead connect it to the dashboard outlets, but prior to 1986 those are not very large.

Figuring out a way to feed into all outlets would be the best but that will need some fabrication of ductwork.

Thanks for the reply! The huge air box under the dash is putting out a lot of air right above the feet on both sides as pictured above. My thought is to cut holes in it and feed the Griffiths vents even though I really do not care for them. Seems to be the easiest way.....

Thanks

[brianlay]

Show us a picture of the dash that shows the outlets.

[steven c]

They are stock.

[brianlay]

Those side vents are ridiculously small but getting air to that center vent might be worthwhile.
The Griffiths vent is just a single outlet under the dash that improves on the factory solution, but it sounds like you're already got plenty of air in the footwells.

[steven c]

Correct, but he sells side vents that go under the dash too. I can hook those up to the air box I have also. All I can think of..... Ugly but better than what I have that just cools your feet?

[brianlay]

Looks like it still uses the feed to the existing side outlets.
You've got some plumbing to do.

[steven c]

Here are the parts I've found so far:

https://www.carbuilder.com/products/2-hole-40mm-od-ducting-flange?_pos=4&_sid=1453e2906&_ss=r

https://www.************.com/Porsche-911SC-1981_p-3253-ventilation-hose-40-mm.aspx

Pelican is blocking Partsklassic on the last link.