EPA quote "A least-cost retrofit, however, may not provide a satisfactory solution for certain vehicles." Meaning = on cars with 40 feet of non barrier hose as compared to a Lexus. Another "EPA" quote "In most cases, the R-12 system hoses will perform well, provided they are in good condition. Cracked or damaged hoses should always be replaced with barrier hoses." So, you gotta wonder, logically, if the EPA 'thinks' non barrier hoses will work just fine ... then why do they suggest replacing old hoses with 'barrier hoses'.

So are DuPont, Goodyear, Parker and many others during the past 20 years have been in collusion?

Quote from Dupont:
"Elastomeric hoses are used in mobile air-conditioning systems and for transferring HFC-134a in other applications. The permeation rates of HFC-134a
and CFC-12 through several automotive A/C hoses were measured as a guide to hose selection The studies were run at 80°C (176°F) with an initial
80 vol % liquid loading of HFC-134a in 76-cm (30-in) lengths of 15.9-mm (5/8-in) inside diameter automotive air-conditioning hose. Hose construction
and permeation rates are summarized in Table 18. Based on these tests, hoses lined with nylon, as well as those made of Hypalon
® 48, appear to be suitable for use with HFC-134a. Note, however, that these rate measurements provide a comparison of the vari-
ous hoses at a single temperature and should not be used as an indication of actual permeation losses from an operating system. "
Dupont Study



Ask the 'certified' buddies what is the purpose of a drier. What are the differences in desiccant types and how are the affected by the different refrigerants and oils. What happens to the desiccant after 20 years of absorbing moisture. How long a desiccant bag will last. What happens when you allow sludge oil in the drier to mix with fresh oil and what affect it has on the compressor and TEV.

No. "He" :) means the black line that is there because oil blew past the compressor nose seal and "IT" attracted what ever.

No. The 86-89 models have a copper manifold bonded to aluminum tubes... and the bond does not last forever and it leaks. Travel over the to the Renn or PP 928 forums and ask our fellow friends about their evaporator issues on 86+ years.

WWest, here you go again. One day you say cars need better condensers and evaporators and other days your choking on your own snake oil thing. Flip-Flop-Flip-Flop.

If you were happy with the factory air and it worked fine a couple if years ago...as long as you dont see any indication of failure, jjust have it serviced with R12...just don't expect it to be ice cold.

Call Griffiths and talk to Charlie. DO NOT listen to wwest in this forum. He obviously has some sort of axe to grind,so he threadcraps every single AC post to try and get his digs in on Griff.

Don't take Griff's word for it - talk to the guys at Rennaire and Retroaire. They will all tell you you stuff that will help in your quest for good AC in these cars. It is possible to get good AC, you just have to spend money.

subscribed

What the EPA meant to say was:
If you have a typical 1980+ front engine car and most of the ac components are located in one area (the front of the car). And assume the flexible hose lines, that were made of non barrier hose, were the connections to the compressor (from evaporator to compressor inlet, compressor outlet to condenser). And, the other lines were fabricated of aluminum tubing (typical for 80+ years and onward), most likely you have about 6-10 feet at most of “rubber” non barrier lines.
Then the rate of leakage “may” not be that significant for the typical car owner who’s jalopy/junker is probably out of warranty (aka 5+ plus year old car); meaning a car owner who does not want to put a lot of bucks to convert to R134 in an old car. So ‘we’ (the EPA) have gotten a lot of phone calls and letters from taxpayers whom are pissed off at us for requiring you to buy new barrier hoses.
So we are going to change our (the EPA) position on permeation (leakage of refrigerant through old non barrier hoses) because we can justify the change based on rumors and phone calls and letters we have gotten from automotive technicians whom also have griped and complained that their customers don’t want to spend the money. So we are going to ignore all the test data we previously had and go with the flow!

Leakage rates of non barrier (stock) hoses vs. barrier hoses
In the study reported by Dupont (and hose mfg's have post like studies) they had 30" sections of 5/8" ID diameter ... various types of barrier hose and non barrier hose. They filled the hose to 80% of its maximum volume with liquid refrigerants (R12 and R134a). They heated it to 176F. They don’t tell us the pressure but we might guess it was 380 psi for R134 and 333 for R12 depending upon your interpretation of temperature/pressure charts (typical of the high side on either an overcharged system or a very hot day, most systems don’t run near this psi range; I’d suggest 225-250 psi is running average while 100 psi is the average “resting” psi when the system is off ). They noted annual leakage rates forecasted to be: for R12 refrigerants to be 1.5 pounds per year with non barrier hoses and .3 pounds per year with barrier hoses; for R134a it was 1.8 pounds per year for non barrier and .2 pounds per year with barrier hoses. Frankly there is a great loss with non barrier hoses regardless of the type refrigerant you use. And logically, the more you use your AC system the greater your losses are, there is a big difference in AC "on" time for someone up in Seattle vs. someone in Houston and likely the same is differences for a 'weekend' driver vs a 'daily' driver.

EPA Flip Flops
The EPA thinks that is not significant today with their flip flop position on barrier vs. non barrier. The EPA one day says coal ash is a hazard and next day it is not a hazard. The EPA flips and flops on lead paint removal methods and shale oil fracking. So Frack the EPA.

The FACTS:
The EPA is addressing vehicles that typically have 6-10 feet of estimated hose in the car with an engine in the front.
A 911 rear engine car is totally different world.
A stock 911 two condenser system has 40 linear feet of hose while a 930 has 43 linear feet.

The Dupont study used 30 inches 5/8" ID hose, 9.2 cubic inches, 60 square surface inches.

Assuming average front engine car estimate of hose is 21 cubic inches, 178 square surface inches.

The 911 and 930 does not use 5/8", rather it uses 5/16", 13/32" and ½" diameter hoses:
or 66 cubic inches, 621 square surface inches.

So the difference between the average front engine car vs. a 911 is:
Front engine car = 21 cubic inches, 178 square surface inches
911 = 66 cubic inches, 621 square surface inches.
The 911 has 214% increase in cubic volume and a 249% increase in hose surface area (the later is more important in terms of permeation).

So a rear engine 911 or 930 can see an annual leakage rate that is 3 to 3.5 times greater than a typical front engine car.

And, the leakage rate per year does not get "better because of oil absorption" in the ID of the old rubber hose. It gets worse. Believe me-you.

Read about barrier hoses in The Mr. Ice Project

Nm

Sorry kid hit the iPhone buttons while I was reading. No message.

You've heard lots of opinions.

Here are some facts.

I have an 84 Targa. I spent a bunch of money on A/C, because I live in a hot state.

I did the complete rennaire system, with the Kuehl serpentine front condenser. If I could do it over again, I'd order the entire system from Kuehl.

With the Kuehl front condenser, Kuehl super evaporator fan, new directional vent (instead of the "bowtie" on the lower vent), new custom aluminum rear condenser, all new hoses, Rennaire Pro Cooler, new compressor and charged with 134, my A/C will keep me comfortable in Texas in the summer. I'm going to tint the windows at some point, since that rear window is like a greenhouse. But - it's all still better than the stock system.

Want really good A/C in a 911? Buy a 993. It's the only air cooled engine car where they finally got it right.

Otherwise, be prepared to spend some major $$ for cold air.

Rennaire ProCooler...

A fool and his money are soon parted.

You could have started, and ended, with a trinary pressure sensor and a fender mounted condensor/fan combination and been well ahead of the game on all counts.

87 3.2 AC recharge
 

Gents - THANKS for your thoughts and for not tearing me up for the low miles :) but the car will be around after the next ice age. Will consider all the thoughts and NO testing of A/C system or disconnect it until I know all is well. I don't use A/C much and try to avoid SLAB (freeway) driving (too many rocks, trucks, SUVs/minivans) and take the Giant Killer out on open winding roads. I don't listen to the radio or have a drink next to me when driving. I have seen the black oil line as noted, years ago, under the engine lid - but that's a thing of the past. The plastic rear window is immaculate - I burnish this with a plastic polish after first carefully removing dirt/dust every few months with a wet towel. Just installed a new ALARM and the boneheads did not clean or unzip the window before dropping the roof and scratched the plastic - they denied but I was able to polish out most scratches. They used connectors in the engine area that lack rubber boots, so I've used electrical tape in a few locations. I wish to keep the beast as stock as possible. Other benefits: look around at a light, everyone is gawking and I get to go first at an intersection even if I'm there last. I believe the DMV has a supplemental regulation that CARRERAS HAVE THE RIGHT OF WAY. Let's hope Rennsport V is in CA, again. Thanks....http://forums.pelicanparts.com/uploa...1368455479.jpg

Just used the "ignore list" for my very first time. Can't wait for WWest to post again...
Thanks to the other posters, I've learned a lot here!

How's this?

Yup. Simple and easy.

I figure that there are some folks in the world that serve as a warning to others. In the aircooled Porsche A/C world, wwest serves that function.

Short version:Griffeth Kuehl system. Save your money and buy the best. I saved for a year, and I have a refrigerator for a Porsche. Charlie's system is just that: Components well built and well engineered. I know a lot of people like to tinker, but the Kuehl components work together to produce ice cold air. None of this "next year I'm gonna..." My 84 Carrera on the highway at 3/4 fan and 60 mph at 110 AZ degrees.Vent Temps were at 34 degrees. And that was with the compressor control only at 6:00. What else do you need? High output blower fan and extra vents. I got everything he has, and I'm ecstatic that I'll be able to drive my car year round. If anybody has any questions, PM me.
Happy almost summer to you all!

I have the same basic system. It works like just like wanted. It still does many years later. No recharge needed.

You heard wwest, that just isn't possible. LIES, all lies!

:)

What I did, 88, black on black, live in LA:

Griffiths barrier hose kit, new front condensor, new evaporator, new drier, rebuilt stock compressor from Griffiths (which was actually a new part), stock rear condensor cleaned with mineral spirits, hi/lo switch.

Charged with R12. I couldn't find any real reason why R134 would be better.

Added the center vent kit and modified the fan with a variable speed switch (all from Griffiths).

The rear coupe glass and rear sides are tinted.

The windshield is coated with 3M crystalline which is a clear tint but blocks infra-red heat.

Front condensor fan lubed, fuse added, fluxing.

Seats have wool fabric centers.

I put a sunshade up if parking in the sun but generally park covered.

Engine aux front Carrera oil cooler with fan and thermostat working well.

Overall it works well. In LA traffic at 105 it starts to strain but that's rare. It's not a Lexus. My goals are not to sweat and not to die.

The only things I would consider are adding a decklid fan (yes, I know) for sitting at a standstill at idle. This is rare so haven't seen the need. Any motion and condensor function seems fine.

I will likely replace the AC blower with the new high volume one...mostly for sound reasons...mine is just loud.

The only other thing would be a crotch blower fan on my recaros....there is a mounting point and it's cool. As Sellers said in The Party: "Oh, I'm on a diet but what da hell"

Please stop miss-quoting me, I have never said these solutions do not work, they work well, assuming you have dug deep enough into your pockets.

It remains my firm belief that you could begin, and END, by adding one of the aftermarket fender mounted condensor/fans and get perfecly adequate A/C capability. You can overcome the non-barrier hose leakage problem at the same time via the use of a trinary pressure switch to run the same fan WHENEVER (ignition/engine on or off)the pressure dictates.

Should you add the decklid fan, or fans, may I suggest you convert the hi/low pressure switch to the trinary one? Then use the new function to run the decklid fan(s) connected directly, fused, to the battery.

As long as we can all agree that Mormonism is the one true religion, this cabin temperature stuff will work itself out in time.

I guess I'll just drive my other car on hot days...