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

[EC900]

I’ll say if that dealer installed ac they took a different route than mine, but as you found isn’t very efficient as to where the air comes out.

Although it appears to be routed to the appropriate locations for an non-ac car, there is no other place to get air to flow except the two tiny side vents (designed to defog side windows) and to the two windshield defrost vents and floor directed openings being the largest.

Not sure what they were thinking - but maybe the slider levers on the controller are not opening or functioning to full range. It looks like the center vent should get cold air as it doesn’t make sense to direct cooled air to lower floor area which is merely a heat outlet. The air flow on output openings should match cfm of the fan without restriction and resistance, so as it’s set up, the evaporator fan output has to being restricted or getting its boost from working in conjunction with fresh air fan.

Something to consider is to check and adjust the dash controller cables are functioning to full range and if the fresh air vent flap is operational or not, which it should be because it’s the only vent large enough to get directed air flow. The slider that directs air to the floor…if open….might prevent cooled ac air to be directed away from the center fresh air vent.

You may need to take the blower off to get an idea of how the air is directed and inspect the flaps, particularly if there’s a duct from the blower to the center vent. I just can’t see why the center vent wasn’t utilized for an aftermarket ac.

For what it’s worth, fresh air always flows through the center vent unless dash slider closes it off (up/down symbol) or the louvres are closed. The fan simply forces fresh outside air into the cabin, but if plumbed for ac the outside opening should be shut or blocked off - no need to introduce humid warm air with ac on.

For reference: Below are pictures of where my dealer installed ac routed, the design never utilized any factory vent plumbing. They cut a hole in the bulkhead (circled in red on your photo) and the cold air came from a central duct there to an under dash distribution console (second photo). Evaporator was behind pass. footboard where they cut a huge 10”x12” hole in bulkhead to draw cabin air to be cooled.






Trying to get an idea of your air flow path looks like this….nothing stands out if it even goes to the fresh air center vent….

[steven c]

Your system is exactly what I have been looking for too, with no luck. Seemed like a good alternative to the Griffiths vents and it looks better to me.

The AC does not go to the dash center vent but lots of fresh air does with the vent open and fan running. Not sure if I tried the outside air blower with the AC fan running though? Thanks!

[pmax]

Originally Posted by steven c

Sorry for the off-topic question but what is that hanging off the drain tube ?

[steven c]

On the brake fluid reservoir? That's the cap that goes over the container to capture any fluid.

[steven c]

Here's a pic from above with it covered.

[pmax]

Thanks, my 80 and 87 doesn't have it. Aftermarket perhaps ?

[steven c]

Originally Posted by pmax

Thanks, my 80 and 87 doesn't have it. Aftermarket perhaps ?

Don't know but kind of cute?

[Jonny H]

Originally Posted by steven c

Slightly left of centre in this photo, there is a 'Y' piece which is capped off. This would have been the original feed to the centre vents. Behind that in the background I see a duct which looks like it still goes to the centre vent. This may now be connected to the outlet of the AC system by the 'new' part below it in the photo. Investigate there.

Being a non AC car to start with, it will have 2 levers on the top row of the slider controls in the cabin. You will need to move the left lever to the left most position to close the foot and screen vents which will maximise the air flow to the centre vent. Also remember that the centre vents can also be closed by a small lever on the vent itself so make sure they are open.

[steven c]

Thanks Johnny! Is this the piece you're talking about? Also, the photo of the new part you mention didn't show up??

[steven c]

Okay, I had a minute between calls to take the pic below of a capped off vent and I'm guessing the plastic accordion vent hose. Are these the 2 to hook together? I do not see a piece on the factory diagram to make this happen though?? Must be a Y of some sort to keep it connected to the vent system too? Thanks @Jonny H

[Jonny H]

Originally the accordion duct would have connected to the capped off top of the Y for non-AC. I think the duct has been re-routed to get air from the blower in the smuggler's box. My guess is that connects to that 'new' plastic part directly below the Y.

When I say 'new' I mean non-Porsche....

[EC900]

Below a pic of my Non-Factory AC but Dealer installed VPC CCCool AC unit (I pulled it out) ducting and distribution boxes.
Yours definitely is not VPC, but notice my original plumbing and how it differs from yours.
Although I only get fresh air (no heat either) coming from center vents, I can’t say how fresh air is actually ducted in unless it’s just a matter of the slider on the dash that opens/closes a flap.

Whatever product brand your set up is, it doesn’t appear to route to the center vent. Not sure why that cap or other splitter is there, other than it being different from mine in the way it distributes cooled air utilizing your existing dash and floor directed vents .

If you manipulate your dash sliders maybe you can determine the air paths. HVAC smoke test would be a nice on get a hold of. Otherwise pulling off the hoses and checking for air movement and your go back and try the slider positioning.

One other thing about your system ….do you have the big hole cutout in the passenger side bulkhead behind the footboard to draw air to the condenser ? Without it it would certainly impede cooling and flow.

[steven c]

Originally Posted by Jonny H

Originally the accordion duct would have connected to the capped off top of the Y for non-AC. I think the duct has been re-routed to get air from the blower in the smuggler's box. My guess is that connects to that 'new' plastic part directly below the Y.

When I say 'new' I mean non-Porsche....

Got it. Not sure as I need to play with the levers and then start disassembly to see what is going on. But I have a path now, thanks!

[steven c]

Originally Posted by EC900

Below a pic of my Non-Factory AC but Dealer installed VPC CCCool AC unit (I pulled it out) ducting and distribution boxes.
Yours definitely is not VPC, but notice my original plumbing and how it differs from yours.
Although I only get fresh air (no heat either) coming from center vents, I can’t say how fresh air is actually ducted in unless it’s just a matter of the slider on the dash that opens/closes a flap.

Whatever product brand your set up is, it doesn’t appear to route to the center vent. Not sure why that cap or other splitter is there, other than it being different from mine in the way it distributes cooled air utilizing your existing dash and floor directed vents .

If you manipulate your dash sliders maybe you can determine the air paths. HVAC smoke test would be a nice on get a hold of. Otherwise pulling off the hoses and checking for air movement and your go back and try the slider positioning.

One other thing about your system ….do you have the big hole cutout in the passenger side bulkhead behind the footboard to draw air to the condenser ? Without it it would certainly impede cooling and flow.

I do not have the big hole for return air, I have a small rectangular grill where the center console meets the firewall and it is sucking a lot of air in with the fan on high. It seems to me that enlarging it would be a good idea and is on my list. Thanks

[EC900]

Ah, that makes sense now. So that photo you posted in comment #21 (the one I circled in red) is not your car Or is the opening hidden by the center console ?

If so, I’d say it’s not large enough to pull sufficiently. The opening can only be as big as that piece of duct so I don’t think it will correct much of the problem. And it still doesn’t solve the problem of getting cooled air to the upper center dash so it can be directed at the driver.

Let me check some files and I’ll try and post a photo of mine after I pulled it out. I know I have install instructions for the VPC system. I think you may, or should be able to salvage something from what you have and get more satisfaction.

[steven c]

Originally Posted by EC900

Ah, that makes sense now. So that photo you posted in comment #21 (the one I circled in red) is not your car Or is the opening hidden by the center console ?

If so, I’d say it’s not large enough to pull sufficiently. The opening can only be as big as that piece of duct so I don’t think it will correct much of the problem. And it still doesn’t solve the problem of getting cooled air to the upper center dash so it can be directed at the driver.

Let me check some files and I’ll try and post a photo of mine after I pulled it out. I know I have install instructions for the VPC system. I think you may, or should be able to salvage something from what you have and get more satisfaction.

Yes, that pic you circled is my car. The return is way below that plenum and maybe an inch or two off the floor hump and hidden by carpet too, it's small. Thanks for any help!

[EC900]

Hope this makes some sense, instructions for VPC setup.
If you were to try to convert or cut out metal, the issues that may arise is your ducting and the manner in which VPC blows air and the way yours currently does.
What important is that I just can’t recall where my VPC fan sat, either on top or at side of the condenser, but the duct forced cooled air out of my condenser and to the 4x6” center opening then into the under dash 4 vent distribution console.
Yours operates in reverse to the way VPC did.
Come to think about it, the large intake opening is cover by floorboard and carpet…the condenser way very dirty and talk about obstruction! Totally against the rules of AC !

[steven c]

I just tried to see more of the return air on my car but, without an engine I cannot move it to get enough room on the passenger side to pull the carpets and floorboard. Looking again from the drivers side there is no grill for the return air. It may be just rushing between the floorboard and the firewall? I need to be able to move the car for the final word on this.

Thanks for the diagram. This is my first 911 older than a 964 and I know how those systems work. I'm figuring this one out slowly. Would be easier if it was a factory supplied unit as I would have the parts pages to help. Thanks

[fintstone]

The return is typically not massive. See the trapezoidal return cut in the passenger footwell which is common for these cars (although some of the aftermarket installs were butchery). It matches up with the same shape on the factory evaporator box on the other side (In the smugglers box):

[steven c]

Well Guys, its been a little while but my motor is still not done and I just finished cleaning up the engine bay, cleaning up some wiring and general tidy up. So back to this again. After thinking about this I opened it up again and the pictures below shows the aftermarket pieces that are throwing the air conditioned air into the fresh air system. Possibly even thru the fan and out the outside air inlet? There may be a damper on that though?? Pics next.



So, this is the bad idea the aftermarket AC guys had and they spent time buying molded pieces to do this with. Not sure if they enlarged the round hole or just covered it with this plastic rectangular piece? The center vent round duct is behind this piece and I'm not sure what is going on with it. That's next to find out?

I'm also not sure how the large plenum under the dash is supplied air but I thought it just went straight thru the AC hole the evaporator fan is connected to, but now I do not think this is correct. I haven't solved anything yet but gathering info for some plan. Maybe I take the black molded piece grabbing the AC air and put the factory pieces that are on Ebay in that will feed the dash center grill? But I do want to keep air in the under dash plenum for more distribution to vents.

Still a work in progress.... any thoughts appreciated.