A bizzare yet pleasing experience...

[jwasbury]

...driving my 930 in the summer, windows up, in comfort. Finally finished an A/C refurbish which has officially been the longest project ever (I finished my engine build faster).

I did not spend a lot of $. New barrier hoses, receiver/dryer, new compressor, everything else is stock. Charged with R134A. It works pretty well. Not making ice cubes, but I don't need to. It's also a revelation to be able to run the A/C to clear up window fogging. In wet weather, this falls into the "safety" category, rather than comfort and convenience.

Happy 4th.

[M5guy]

Enjoy it!

A few years ago I did the full Mr Ice treatment on a 76 930. It would turn your kneecaps blue and keep beer cold, but it also cost about $4k.

[WPOZZZ]

I took out my turbo tonight and experienced the same sensation! I was also relieved that installing a new fuel filter and accumulator cleared up my warm start problem. Now I don't have to worry if the car will start after I take her out for a bite to eat or go to the movies.

[gsxrken]

Timely post... Its been incredibly humid in the NY metro area. Just last night, I took my 930 to a wake and as I immediately reached for the AC knob, I was once again reminded of how well that money was spent. I wouldn't have otherwise even thought about taking the car. Instead, I ripped its lungs out on a second gear blast to redline and then enjoyed exhaust note, and had a pretty girl smile and wave at a traffic light.

[JFairman]

If you can get vent temps that are 45-50 degrees cooler than outside ambient temperature using R134 you're doing really good in a 930.
Especially on a sunny 95 degree day with the sun baking the roof and coming in the windows in the afternoon while driving.

Add to that all the hot air from the front trunk that is drawn into the interior through all the holes in the front cabin bulkhead area and expelled through the large horizontal roof vent at the top of the rear window while the car is moving.

...The little evaporator inside the plastic box stuffed down into the 911 chassis smuggler box has a hard time keeping up.

If we could still get R12 maybe the AC would work good during summer in south florida...

[JFairman]

I've got a 1987 930 rear condensor for sale on the classifieds. I replaced it with another one just like it that looked a little better hoping to get lower vent temps but they are exactly the same as before with this condensor so I know this one works good.
It doesn't leak.

$80 plus shipping in the USA.
FS: AC condenser for 911 turbo tail

[jsveb]

AC Is one of those things, I do not have a clue about.

It is a dark art for me. My car has got extensive updates :under belly condenser etc., but still not impressed. I guess it is just old.

Congrats.

[JFairman]

I know automotive AC very well and the no longer available 911 underbelly condenser is the best and most efficiant heat exchanger there is for cold AC as long as it's in good condition and the car is moving so air is flowing over it. I say it's most efficiant because it has no fan and doesn't tax the alternator of battery because of that.

It won't do anything while the car is stationary or moving slowly over hot asphalt or pavement though. It's good to have the front condensor and fan working and another one in the tail with a 10" fan pulling air down through it if you have a halfbay intercooler or another condenser in the left rear fender well with a 10" fan pulling air through it in front of the left rear wheel if you have a full bay intercooler.

Don't bother with an overpriced BS procooler. It doesn't remove any heat from the system, it only transfers some heat from the high side over to the low side. It's total snake oil and a waste of money. It's also very expensive to replace when you need a new reciever drier. Like 4x what a plain old reciever drier cost.

If thats not enough there's still room for another condenser and 10" fan behind the left rear wheel in the 930 flared fender well.
Too many condensor fans running at once will make the car sound like a hovercraft and overload the alternator and drain the battery though. You still have the origonal front condenser fan and AC blower fan running in the evaporator box.

[M5guy]

Originally Posted by jsveb

AC Is one of those things, I do not have a clue about.

It is a dark art for me. My car has got extensive updates :under belly condenser etc., but still not impressed. I guess it is just old.

Congrats.

I used to think AC was mysterious, but its really pretty simple. It only has five major parts and some hoses, fans, and switches.

One day I was at the local car AC experts place, and I discovered that the expert was illiterate. Literally, illiterate. It was an epiphany, and I went home, bought a gauge set, a sniffer, and a vacuum pump, and just do it myself now.

R12 works a little better, has something to do with molecule size, but when I had my 84 Targa retro'd back to R12, it cost $450 for the freon, and I had to pay a licensed shop to do it. r134a would have been about $50 at Sams Club.

[RarlyL8]

My '85 slant came with 2 condensers, one in the tail and one underbelly. I had our mechanic replace the comressor seals and fill the system with R12; the system works great! One of the reasons I bought this car was for A/C. The red rocket was a factory A/C delete car which was torture now that I live in AL.

[jwasbury]

Originally Posted by JFairman

If you can get vent temps that are 45-50 degrees cooler than outside ambient temperature using R134 you're doing really good in a 930.

I doubt I am getting 45-50 degrees cooler than ambient vent temps. That's honestly more than required for my needs. This was my first foray into A/C service, so I am simply happy to have it working at all. Haven't even gotten to the point of trying to optimize it. Most of the $ I spend on this car now is track use oriented. The A/C is keeping things "civilized" on the way to/from the track.

[speednme1]

Absolutely needed with the current temps, I called Griffths last week, as ac is something I want working in my car. Price was a bit high but I'm sure it's worth it. Once the work is done on my car I will shake the piggy bank once more in the hopes that a few coins will come out for some ac work..

[1986 930]

I am in the same boat. I am thinking about doing the basic upgrade. The barrier hoses and the extra condenser in the wheel well thing. I don't need to be frozen just cooled so I wonder how far you really need to go. The difference between the requirement and the wouldn't it be nice thing.

In Florida Summer, the car just can't be driven all that much if you want to go anywhere and not look like a mop when you get there. Nothing is worse that getting caught by a rain storm during summer in a 930 without a good AC.

[slow&rusty]

Jacob - Can you share you share your AC project, similar to your engine build?

Thanks - Yasin

[SCHNELE]

Or you guys can buy my 930 with working air! I have two Griffiths condensers in the left rear, the factory front and the desert duty underbelly, barrier hoses etc, 134A gets cold but still not modern AC. I like to be freezing on my drive.

[JFairman]

The '86 evaporator in the smuggler box in your car is a good one and that doesn't neeed upgrading. They redeigned and improved it starting around 1986 when they changed to the larger square side AC vents and bigger center vent in the dashboard.

You can get decent AC in your car by putting a 10" puller fan on the rear AC condenser like this one:
Size 10 pull / Part# 0360 - The Fan Man
Wire it up to the wire that engages the compressor clutch so the fan comes on when the AC compressore engages.

Then install this serpentine condenser that comes with a 10" fan on it in the left rear wheel well in front of the wheel:
911 COOL Air Kit
It's best to wire it's 10" fan and the other 10" fan you put on the rear condenser to a seperate relay triggered by the AC compressor wire so the factory relay in the smuggler box that turns on the evaporator fan and engages the compressor clutch doesn't get burned up wit all that amperage going through it. Use the big 12volt supply wire on the starter motor that isn't far away on a 911 for power to the extra fans you install.

Then replace the receiver Drier behind the left front wheel and evacuate the system for a minimum of 3 hours to boil out all the moisture and Florida humidity in the 40 feet of hose and heat exchangers in the AC system. Then charge it.

R12 is probably best if you can find it but R134 is still easy to find. I don't have experience with all the other alternative regrigerents mentioned in this thread.

If you have the AC manifold gauges charging from a 30 pound bottle is easiest and best.
Slowly partway unscrew and purge the 3 hose fittings on the manifold until cold refrigerent sprays out of the slot in the female threads to get the Florida air out of the hoses and then retighhten the hose fittings and you're ready to charge it.

Here's the best price I've found on 30 pound bottles of made in USA name brand R 134a
Dupont Suva 134a 30lbs Can Refrigerant R 134a Factory SEALED | eBay

It's best to start the charge on the high side with the refrigerent bottle upside down so liqued refrigerent is filling the system on the high side of the compressor with the motor not running.
When that has equalized with the pressure in the bottle and stops flowing in close the manifold gauges and turn the bottle right side up and open only the low side of the manifold gauge so gas refrigerent will start going in.

Now start the motor and turn the AC on high with the rear lid closed down gently on the hoses and continue charging in the low or suction side of the compressor with the bottle or cans right side up so only gas refrigerent is being sucked in.
You don't want to let liqued refrigerent go in the low side with the compressor engaged and running because that can hydralock and stress the compressor and possibly blow out a shaft seal on it.

With R12 the pressures are more forgiving and they will be around 25-30 on the low side and around 225-235 on the high side in 85-95 degree weather. You can also watch the window on the side of the 911 reciever drier and stop when bubbles dissappear with R12 but that doesn't work with R134. The bubbles never go away with R134 when the prssures are correct.
Pressures go up with ambient temps and there are charts you can find online.
If using R134 it's a little trickier to get the pressures right and they will always be higher than R12.

You can keep the origonal hoses with R12 and you will need to replace all the hoses with AC barrier hose if you use R134 and don't want it to leak out.

good luck with it.

[slow&rusty]

Originally Posted by SCHNELE

Or you guys can buy my 930 with working air! I have two Griffiths condensers in the left rear, the factory front and the desert duty underbelly, barrier hoses etc, 134A gets cold but still not modern AC. I like to be freezing on my drive.

Uh Oh...and there it is..

[jwasbury]

Originally Posted by slow&rusty

Jacob - Can you share you share your AC project, similar to your engine build?

Thanks - Yasin

Yasin,

Not much to share, really. I was going for a cheap solution...not "Mr. Ice project"

I bought a barrier hose set and 134a compatible receiver dryer from Rennaire. Their hose kit was significantly less expensive than competitors IME. Removed original hoses and receiver dryer. Installed new. Pulled front and rear condensers and flushed with cleaner solvent. All fittings treated with "leak lock" goop (my car has all flare fittings rather than o-ring style. My car came with a Sanden Compressor which I planned to reuse, but it was submerged in salt water during Hurricane Sandy flood. It probably can be rebuilt, but I just bought new from our host. The compressor came pre-filled with oil. I dumped the oil and replaced with 6 oz of PAG.

Bought 2.5 CFM vacuum pump and A/C manifold gauge set from Harbor Freight (cheapest available). I used my trusty harbor freight vac pump, pulled a vacuum for 1/2 hour, then shut down to see if the system held vac. It did hold...no change after 48 hours. Time to charge. Vacuumed system for about 1.5 hours. It took about 2 cans of R134a. Low side pressure was 35-40, high side max 250. Ambient around 80. I think I can do better, but This being my first go, I am happy with that.

Drove the car 200 miles yesterday to/from the track and ran the A/C nearly the whole time. Ambient temps in the low 90s and humid. In full sun, the cockpit is not real "cool" but the system keeps things reasonably comfortable, windows up. Much better than windows down. Makes the car car much more comfortable to drive distances in this weather. In partial sun, the A/C does better. As a point of reference, at home and in the CTS-V where I have auto climate control, I tend to set no lower than 77 degrees, so this gives you a reference point. I don't like to be refridgerated.

[Ronnie's.930]

Originally Posted by slow&rusty

Uh Oh...and there it is..

I noticed that as well - time to cut and run?

[jwasbury]

Originally Posted by Ronnie's.930

I noticed that as well - time to cut and run?

Yeah Linc...please explain.