Retrofitting non-A/C ventilation ducts

[huba]

Just got done glancing at all the posts on a/c venthoses and routing. I'm totally be fuddled by the hoses and connections involved in this system. I have a 1978 SC with what I think is factory a/c. Everything under the hood was disconnected. I was able to hook things up to get heat and since I don't drive it much it's not a concern as yet. But eventually I'll want to hook up the a/c and retrofit a new compressor. I'll definately will need help. How do I save this thread to return to later when i'm ready? Huba

[Vin-barrett]

Originally Posted by huba

How do I save this thread to return to later when i'm ready?

by posting on the thread you've basically saved it already....
If you search your own name you can see your posts and what thread they were in

[javadog]

So, I noticed this thread has resurfaced. To answer some of the questions posed, I wish I could help you with the part number of the "t" piece from the photo of the brown car but that car was sold to a guy in Germany a couple of years ago.

As for the linkage on thw white car, I shot a few photos today that should illustrate how it goes together.

Cheers,
Jeff

[frankc]

Jeff,
Thanks very much for posting the detail of that linkage attachment. I now see that there is a difference between the valve lever on your setup and mine. On yours, the S-Bend on the short linkage fits into a hole on the valve lever. The lever on my car does not have that hole, and looks a little shorter. I'll snap a picture and post it tomorrow to show what I mean. But since it's just a hole, I can drill that if there's room .

[frankc]

Good news - it appears the levers are actually the same length, it's just that the hole for the extra linkage is missing on mine. Here are a couple close-ups of what I have:

[Vin-barrett]

good info

For the sake of reference, my 1983 car already has these holes in the lever

[frankc]

Vinny,

Lucky you . Actually, thanks for posting the picture - I did not notice there were two holes as the one is mostly hidden in Jeff's pictures (not that I need two).

[Kraftwerk]

I am in the process of replacing the blower motor and re-channeling former A.C. vents to fresh air vents. All this info has been helpful. Will have more questions, but first what is the best way to 'split the case" to get the hamster-cage fan and motor out of there? Do those round clips go back on easily? What is the Ford NAPA number for the fan motor ? The one given a few years ago is no longer a valid part number on the NAPA site. Edit: I bought the Bosch fan, easy-peasy to install...
Thanks!

[Tidybuoy]

Subscribing. looks like an interesting project.

[Kraftwerk]

Originally Posted by Tidybuoy

Subscribing. looks like an interesting project.

Yeah and the pictures have been great so far.
What I would actually like to see is somehow, someone take a ventilation fan and plumbing from a newer car, a Mazda or something and replace everything in the SC so it is lighter and functions just as well or better than stock using this newer lighter stuff.
But this thread has me going in the stock no-ac direction, for now.

[quattrorunner]

bump for future project

[Kraftwerk]

From the first and second drawings in the original post: Can part number 6 (in first drawing) be turned upside down and fitted to part number 20? (second drawing) and why not? Seems like that would get fresh air to the 3 dash vents Left, Right and Middle. I am interested in fresh air from these 3 vents. Which are now 'dead' since I ripped out the working A.C. (its for sale!) Heat is not lacking in my '83 SC when I need it....and even when I don't... hence the quest for more fresh air blasting through the cockpit. Its nice at around 80 mph to have all major ports shut and the air "blasting" 'cept right now it ain't.

ps. The one thing I like about the Carrera is the dash vent, it looks huge in comparison to the SC center dash vent.

[javadog]

If you have part number 20, you don't need 6. All you're trying to do is get air to the center vent. It's already supplied to the side vents through other hoses.

JR

[frankc]

Kraftwerk,
If I understand your question correctly, you are asking if part 20 can be used in-line after part 6, and I assume you are asking because you would like to avoid replacing the A/C L & R control boxes (parts 4 & 5 in 1st pic) with the non-A/C boxes (part #18 in 2nd pic) that have the feeds to the L & R dash vents?

I suppose this could be made to work, but then realize that you will be feeding 4 vents from the right side port of the blower (R control box, center dash vent, L & R dash vents), so the air flow may not be that great. However, I suppose this is not too much worse than the OEM setup where 3 vents are fed from that same port (R control box/dash vent, center dash vent).

Let me know if you need any pictures to show how the various tube sizes match up.

[javadog]

I thought the distribution boxes were all the same. If not, there are some pieces shown in diagram 813-10 in PET that might be helpful. Personally, I wouldn't care about fresh air to the left and right dash vents in an '83. Not enough to matter....

JR

[frankc]

Javadog,

It's actually just the "caps' on the control boxes that are different between A/C and non-A/C setups (see the pictures in my first post). Unfortunately, one is unable to purchase the caps separately - at least from the supplier - as they come as part of the control box assembly. The difference being that the non-A/C setup taps the airflow for the L & R dash vents from the top of the control boxes (diverting some air from the windshield defroster vents), where the A/C setup taps the airflow for the L & R dash vents directly from the A/C evaporator blower.

I was lucky and found someone selling some used non-A/C control boxes that was willing to sell me just the caps.

[javadog]

I suppose we'll never really understand what Porsche did, or why... For what it's worth, the brown car in my pictures was a 1980 ROW 930 that I owned for a period of time. It was originally fitted with A/C, as that was standard on all turbos. Of course, I later removed all that crap, since it didn't work very well anyway... So, what's odd is that it had the same distribution boxes as the white car (ROW 1977 Carrera 3.0), which never had A/C fitted, and both of them had the tubes for ducting air to the side vents. In other words, the air distribution boxes were the same.

JR

[stormcrow]

This is what I did to my A/C system - removed the outside air blower and just used the A/C blower - A/C is still working but you can just use the fan to mix with air from the heater if necessary

[frankc]

Javadog,

Yes, that is strange indeed. I can see from the photos of your white and brown cars that both have what the PET diagrams indicate as being the non-A/C style control boxes. So did the A/C blower supply cool air to only the center vent in the brown car (before you removed it)? Or did it also feed into the control boxes somehow? From what I have seen in the 911, Porsche always kept the A/C and non-A/C air separated via independent ducts, so the latter would be odd.

I just can't imagine the center vent alone being able to supply enough air to cool the cabin, but then again the side dash vents are so small (on the pre-84 cars) that they probably don't contribute a whole lot of additional volume anyway.

Yes, certainly a mystery.

[frankc]

Stormcrow,

Just so I understand your setup, the only way to get "fresh" (i.e.; non-recirculated) air into the cabin is to open the heater valves (or roll the windows down ), since the A/C blower draws its air from the cabin, correct? Which, for A/C in a 911, is probably what you want anyway.