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Help design my a/c hose routing

1980, converting to 134, need all new hoses.
I have an underbelly, decklid and front condenser.
Will not be switching to any new brands. all of the condensers/evaporator/compressor are in good shape. Only moving hoses.

I hoped to just repair the hoses I have, but it turns out that the system that the PO put in about 10 years ago was NOT barrier hoses, like I thought (the crimps run along the hose, not perpendicular to it). So, need all new hoses, which is fine (some are damaged, some are old, some are going to be too short, etc, so wwest, you can keep your "barrier hose is useless" stuff to yourself).

I would consider adding a handbuilt condenser in the front driver's wheelwell. Don't exactly want to, but would consider it.

So, give me some ideas. The current routing is compressor-underbelly-decklid-front-dryer-evaporator-compressor.

Options I've considered:
1) underbelly-decklid-front
2) decklid-underbelly-front
3) REVERSE THE GAS
4) add a wheelwell, go underbelly-wheelwell-front and delete the decklid
5) add a wheelwell and go all out, decklid-underbelly-wheelwell-front

Or, delete the front and add a wheelwell, which opens up a future IROC bumper or oilcooler or something.

I'll be making all my own hoses and doing my own charging, so some experimenting is an option. SOME experimenting, mind you...

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1980 911SC sunroof coupe, silver/black
Putting the sick back into sycophant!
Old 07-13-2015, 08:08 AM
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El Duderino
 
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Oh, lordy. You're just asking for it aren't you?

I would think Option 2 would be the shortest in terms of hose routing.

Having recently pulled new hoses, one thing to keep in mind is that you just want to make sure you maintain ground clearance.

Has your system worked at all since you've owned it? If so, would you say that the cooling capacity was sufficient? That should give you some general indication of whether you need to increase condenser surface area or not. Then next things to consider would be the effect of increasing evaporator surface area and fan speed.

Now that the pin has been pulled on this grenade, I'll take a step out of the blast radius.
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Old 07-13-2015, 08:57 AM
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Quote:
Originally Posted by Pazuzu View Post
1980, converting to 134, need all new hoses.
I have an underbelly, decklid and front condenser.
Will not be switching to any new brands. all of the condensers/evaporator/compressor are in good shape. Only moving hoses.

I hoped to just repair the hoses I have, but it turns out that the system that the PO put in about 10 years ago was NOT barrier hoses, like I thought (the crimps run along the hose, not perpendicular to it). So, need all new hoses, which is fine (some are damaged, some are old, some are going to be too short, etc, so wwest, you can keep your "barrier hose is useless" stuff to yourself).

I have NEVER taken the position that barrier hoses are "USELESS".

My position has been that by restricting the high side pressure to limited range the non-barrier hoses will not leak, most especially post conversion to R-134a. And as you know both the US Government and Dupont support that latter position.


I would consider adding a handbuilt condenser in the front driver's wheelwell. Don't exactly want to, but would consider it.

So, give me some ideas. The current routing is compressor-underbelly-decklid-front-dryer-evaporator-compressor.

Options I've considered:
1) underbelly-decklid-front
2) decklid-underbelly-front
3) REVERSE THE GAS

Ask Charlie what he thinks of this...

4) add a wheelwell, go underbelly-wheelwell-front and delete the decklid
5) add a wheelwell and go all out, decklid-underbelly-wheelwell-front

Or, delete the front and add a wheelwell, which opens up a future IROC bumper or oilcooler or something.

I'll be making all my own hoses and doing my own charging, so some experimenting is an option. SOME experimenting, mind you...

6) eliminate the underbelly... subject to debris and radiant roadbed heat, add the fender well blower/fan. Front fender most desireable, only radiant heat source would be the tire, and you could run the fan(s) from a thermostatic switch on the R/D just as Porsche did with some models.

My only direct experience with the underbelly condenser is having purchased a '79 Targa in Salt Lake. A/C thermostatic switch had failed and upon repair I was advised that the belly condenser had been bypassed.

Contacted the PO who said the underbelly condenser seemed to work fine in NJ where he lived previously, but was advised that the poor performance in SL was due to the lack of efficiency of the underbelly condenser.

He said that after bypassing the underbelly condenser he felt the A/C worked better.

If it is true that the belly condenser is no longer available there might be good reason.


NJ vs Ut..???

Last edited by wwest; 07-13-2015 at 09:06 AM..
Old 07-13-2015, 09:03 AM
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Quote:
Originally Posted by Pazuzu View Post
1980, converting to 134, need all new hoses.
I have an underbelly, decklid and front condenser.
Will not be switching to any new brands. all of the condensers/evaporator/compressor are in good shape. Only moving hoses.

I hoped to just repair the hoses I have, but it turns out that the system that the PO put in about 10 years ago was NOT barrier hoses, like I thought (the crimps run along the hose, not perpendicular to it). So, need all new hoses, which is fine (some are damaged, some are old, some are going to be too short, etc, so wwest, you can keep your "barrier hose is useless" stuff to yourself).

I would consider adding a handbuilt condenser in the front driver's wheelwell. Don't exactly want to, but would consider it.

So, give me some ideas. The current routing is compressor-underbelly-decklid-front-dryer-evaporator-compressor.

Options I've considered:
1) underbelly-decklid-front
2) decklid-underbelly-front
3) REVERSE THE GAS
4) add a wheelwell, go underbelly-wheelwell-front and delete the decklid
5) add a wheelwell and go all out, decklid-underbelly-wheelwell-front

Or, delete the front and add a wheelwell, which opens up a future IROC bumper or oilcooler or something.

I'll be making all my own hoses and doing my own charging, so some experimenting is an option. SOME experimenting, mind you...
I'd say option 1, which in essence is very similar to "reverse the gas" since you are not dumping all the heat in the decklid and the engine. Keep your current setup if you are happy with the cooling it provides. If your compressor is in good shape you will only need to replace the R/D.
Can you share pics of your underbelly setup? How is it protected from the road debris (guard, etc...)?
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Old 07-13-2015, 09:15 AM
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If you want to take Mr. Wests' advice and get rid of the underbelly, I'll be more than happy to take it off your hands. Every car I've ridden in that had it, had excellent a/c.
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Old 07-13-2015, 10:13 AM
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The underbelly condenser stays, the car had frighteningly cold air the first summer I owned it, but a mistake with the fitting on the compressor blew all of the freon out one day. Hasn't worked since, haven't put any effort into making it work.

The setup now involves loading the underbelly first, which will take heat soaking away from the engine bay, but involves probably 10 extra feet of hose. Not a huge deal, but something to think about. I daily drive the car, but i'm on surface streets in basic 30mph traffic, not stuck in gridlock. I know the underbelly is worthless when sitting still in Houston, but that rarely happens to me.

Do i need a new fender condenser? no, but if that could/would allow me to remove the decklid one, then it's probably well worth it. I have seen people mention running a fender system and removing the decklid stuff, but no actual reports of anything doing that (as a retrofit on an older car, of course).


Currently the underbelly has basically no protection(well 2 1/8th in straps that hold it in place). The fins are thick and after 10-12 years show no damage. Car is at Euro height.



I will probably stick with current route (belly-decklid-front). It's not the shortest run, but the routing is there now to follow, and any strain taken off of the engine temps is worth it.


Oh, I'll likely toss a fan in the decklid, because there's room and it won't hurt.
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Mike Bradshaw

1980 911SC sunroof coupe, silver/black
Putting the sick back into sycophant!
Old 07-13-2015, 10:36 AM
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I Have an underbelly unit, I've been looking at using it for years and still haven't installed it but will. I've read soooo many good testimonials with it that I just want to use it. BTW if you've ever seen one you'll see that it's not that vulnerable. It's stout to say the least. The fins are thick, the lines are also thick. The whole thing can take a rock hit and keep pressure by the look of it.
But, the fender units with fans make perfect sense and the latest AC thread that hoteuro shows only one decklid condenser system shows that three condenser systems are silly. Get a good condenser or two and be done with it. The hoses you're replacing will go a long way too.
I'm pulling for you, I'd bet you'll have a great system once all buttoned up.
I'll be watching this one with interest unless it gets too heated and if that happens, I'll just do like I always do and hide in the turbo/930 section for a while.
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Old 07-13-2015, 10:56 AM
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Mike If you can, please post a pic of that underbelly, how big is it? And...
If at some time it was "frighteningly cold" then it sounds like you answered your own question.
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Old 07-13-2015, 11:01 AM
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With making up new AC hoses, there are the newer, smaller diameter barrier AC hoses available. You are most likely aware of them, but if not, they are a lot smaller diameter and much easier to run thru the chassis. I had some new barrier hoses made up for my
car at a local industrial hose/fittings company, unfortunatley they didn't inform me of the smaller hoses till mine were already made up. Drat the luck!!
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Old 07-13-2015, 12:14 PM
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I won't let this thread become a CF. I will make sure to have Red-Dot brand trinary switches on both ends of the car feeding their respective Spal fans. I will not drive without removing the heat soak from the passenger area by opening all windows first. I will get the darkest legal tint for my sunglasses. I will crystallize the windows with heat rejecting crystals. I will remember that I am an uneducated redneck Texan
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1980 911SC sunroof coupe, silver/black
Putting the sick back into sycophant!
Old 07-13-2015, 12:22 PM
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Quote:
Originally Posted by uwanna View Post
With making up new AC hoses, there are the newer, smaller diameter barrier AC hoses available. You are most likely aware of them, but if not, they are a lot smaller diameter and much easier to run thru the chassis. I had some new barrier hoses made up for my
car at a local industrial hose/fittings company, unfortunatley they didn't inform me of the smaller hoses till mine were already made up. Drat the luck!!
They are an option, at least the the reduced #8 hose is. It uses the same crimping dies as the normal #6 hose, so I thought I might use normal #6, reduced #8 and a single run of normal #10. Instead of buying extra dies at $70 each.

I will say that the reduced hoses are only about 20-25% smaller, and since I'm replacing good old fashion R12 hoses, the routing shouldn't be much of a problem.
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Mike Bradshaw

1980 911SC sunroof coupe, silver/black
Putting the sick back into sycophant!
Old 07-13-2015, 12:25 PM
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Quote:
Originally Posted by Pazuzu View Post
The underbelly condenser stays, the car had frighteningly cold air the first summer I owned it, but a mistake with the fitting on the compressor blew all of the freon out one day. Hasn't worked since, haven't put any effort into making it work.

The setup now involves loading the underbelly first, which will take heat soaking away from the engine bay, but involves probably 10 extra feet of hose. Not a huge deal, but something to think about. I daily drive the car, but i'm on surface streets in basic 30mph traffic, not stuck in gridlock. I know the underbelly is worthless when sitting still in Houston, but that rarely happens to me.

Do i need a new fender condenser? no, but if that could/would allow me to remove the decklid one, then it's probably well worth it. I have seen people mention running a fender system and removing the decklid stuff, but no actual reports of anything doing that (as a retrofit on an older car, of course).


Currently the underbelly has basically no protection(well 2 1/8th in straps that hold it in place). The fins are thick and after 10-12 years show no damage. Car is at Euro height.



I will probably stick with current route (belly-decklid-front). It's not the shortest run, but the routing is there now to follow, and any strain taken off of the engine temps is worth it.


Oh, I'll likely toss a fan in the decklid, because there's room and it won't hurt.
Given that the "first in line" belly condenser obviously works so well for you I wouldn't hesitate adding a condenser/fan in the front(***) of the rear wheelwell and remove the rear lid condenser once the new configuration has proven itself.

On the other hand if you should add the fender mounted condenser/fan it might be wisest to make the new, more efficient (forced air cooling)condenser/fan "first in line".

Short hose runs to boot.

*** The radiant heat from the exhaust/engine/catalyst may well be so minimal that it only has a 5-10% negative effect but why bother since the alternative is readily available.

Last edited by wwest; 07-13-2015 at 12:38 PM..
Old 07-13-2015, 12:28 PM
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Quote:
Originally Posted by ganun View Post
Mike If you can, please post a pic of that underbelly, how big is it? And...
If at some time it was "frighteningly cold" then it sounds like you answered your own question.
Here are two.
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Old 07-13-2015, 12:35 PM
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OK... someone has to say it...

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Old 07-13-2015, 12:37 PM
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Quote:
Originally Posted by wwest View Post
Given that the "first in line" belly condenser obviously works so well for you I wouldn't hesitate adding a condenser/fan in the front(***) of the rear wheelwell and remove the rear lid condenser once the new configuration has proven itself.

*** The radiant heat from the exhaust/engine/catalyst may well be so minimal that it only has a 5-10% negative effect but why bother since the alternative is readily available.
I actually wanted to go into the front of the front wheelwell, where the washer bottle is. That way, the flow path would be very direct, compressor-underbelly-fender-front-dryer-evaporator. The hoses would "mirror" the oil lines under the edge of the car.

I've also been looking at bulkhead fittings for A/C o-ring fittings, and wondering if there is any routing that might be easier going through the frunk...
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Putting the sick back into sycophant!
Old 07-13-2015, 12:38 PM
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Originally Posted by quattrorunner View Post
Here are two.
Mine looks like the one of the left. About 3/4 thick total, with the shield endcaps like that. It runs almost to the oil lines left-right, and, what, 18 inches front to back?
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Putting the sick back into sycophant!
Old 07-13-2015, 12:39 PM
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These are identical just one is turned around
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Old 07-13-2015, 12:47 PM
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Originally Posted by quattrorunner View Post
These are identical just one is turned around
Forced perspective made the one of the right look about twice as thick.
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Putting the sick back into sycophant!
Old 07-13-2015, 12:49 PM
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I wonder why they quit making them? The sheer size of them makes up for any inefficiency. The ones I've seen look like they are steel. Is that so?
I think it was Performance Aire that sold them.
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Old 07-13-2015, 02:12 PM
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Originally Posted by RSTarga View Post
I wonder why they quit making them? The sheer size of them makes up for any inefficiency. The ones I've seen look like they are steel. Is that so?
I think it was Performance Aire that sold them.
Not sure why they quit but I wouldn't want one because I don't need anything hanging any lower below the car. Seems like road debris and snagging on speedbumps is a possible downside.

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Old 07-13-2015, 02:38 PM
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