TOXNER

Each year it gets more difficult to drive my 85 911 during the summer months. I live in Arkansas where it is both hot and humid. The car is black inside and out. has anyone used the A/C upgrades advertised by various vendors? Did they work well or not so well? Thanks for any information you may have.

Tom Oxner

ulrichd

Tom,
Here is a good source for all of your a/c questions.
Ulrich

http://www.griffiths.com/porsche/ac/ice/index.html

Peter Zimmermann

Tom: Always remember, your car was the last year of small dash vents, so the amount of cooling is greatly restricted by the amount of air the system will flow. My SC is an almost identical system to yours, and it will not keep up with Bakersfield (Central CA) summer temps (95 - 115). There are a lot of improvements/devices available, but talk to PCA members in your area before spending lot's of money, and ending up being disappointed.
Pete

Jay Gratton

Tom,
A few years ago I had my '85 911 down in Tampa for the PCA Parade. I had the AC charged right before I left and it did nothing while I was down there. I was better off with the windows open. Those vents are to small to do ANYTHING! I feel your pain my friend. But try driving a 914 on the other hand. That engine is a few inches behind your back. On a hot day that my friend is HOT!!!!!

TonyG

Here's your solution:

http://www.fastraceproducts.com/fres...it_systems.htm

Don't laugh... it works :-)

TonyG

TonyG

TOXNER

There is no good solution.

But the first thing I can say is the the small side vents are not your problem. If you actually take apart the a/c system, you'll see that the size if the duct going to the side vents is plenty large to flow lots of air. Also, the side vent is not a restriction. The problem is that not much air is directed to the side ducting in the first place. Why is a different issue.

Do you have the a/c vent below your ash tray on the bulk head? The one with the cover using two 10mm screws to hold it down? If you do, remove the cover. You will see a LOT of air come out through there. If you don't, then you need to compare your a/c system to a USA SC system, and get the duct put in that runs to the lower bulk head.

My SC has a stock a/c system, and it blows a ton of air through the center vent and through the lower bulk head duct. Not much comes out of the side vents. But in the last 993's I've driven, not much air came out of their side vents either (more than ours... but not by much).


Assuming that you have a factory a/c system, with both the front and rear condensers, the other thing I did was to remove the stock front squirl cage blower fan in the trunk. While squirl cage fans are great, the way the factory fan is ducted results on air only going through about 15% of the front condenser. I cut in another rectangular hole, identical to the stock hold, on the opposite side of the front condenser. I then use some high powered 12vdc fans on top to blow through. 2 on one side, and 2 on the other. The result was that air can now be felt coming through the entire area of the consenser rather than only on one small corner.

On an 85F day in the shade, on a stock SC system with R134a, I can get 39F center vent temps within 2 minutes at 2000 rpms.

It asn't no Ford truck a/c system, but it's good enough to get by.


TonyG

Peter Zimmermann

Actually, the A/C in my Ford truck sucks too! And we're not talking 85 degree days, we're talking 95-115. My Touareg is perfect in that heat, my 325 is adequate, SCs and early 3.2 Carreras are a joke. Over many years I've had many customers contract us to improve the A/C in their '85 and earlier cars. We've put extra condensers with fans in Turbos, we've put belly condensers in SCs, we've opened up the under ashtray vent and added a directional vent to the hole, we played with expansion valves and condenser blowers, we installed rotary compressors and new receiver/dryers, blah, blah, blah. We've seen 33 degrees at the center nozzle on a number of cars. On a 100 degree day in the San Fernando Valley the A/C still sucked. One of the problems is that the vent temperature goes up when you kick the evaporator housing fan up to speed #2, and goes up again when you kick it up to #3. So, you've got nice cold air at low volume (33 degrees), not so cold air on speed two (38 degrees), which is still inadequate, and even warmer air (42 degrees) on speed 3, which is still poor compared to a 964 or 993. In Bakersfield you open the windows and deal with it (yet another problem - the car will overheat in traffic with the A/C on), or you drive your other car.
Pete

redidrum

About $1200 later here is what I did and my 82' is very vool. Changed all barrier hoses, rotary compressor, receiver/ dryer in w/w, condensors checked and cleaned, new a/c blower in front, sealed all connections in a/c box in trunk front r/h side pit, blocked lower vents to blow on top only, leak down for 24 hours, and serviced with R-134a. Big job, but, worth it in the end. Couldn't do it all without reputable a/c shop on Porsches. Parts available. Good Luck, Ron

Peter Zimmermann

Ron: You got a helluva deal! I know an A/C shop in SoCal that would have been somewhere in the $2200 - 2500 range for the same job. I know a shop that charged $900 just for the barrier hoses, and another $650 for the compressor...
Pete

TonyG

Peter Zimmermann

First off, my setup did not use the condenser on the rear deck lidm for the exact reasons you specified... over heating. No conderser on the rear deck lid = no overheating with the a/c on.

Secondly, I live in Valencia. It's just as hot here as it is in Bakersfield in the summer.

Third. Every Ford truck I've had has had ice cold a/c. Even in Phoenix Az in the summer, it's always been ice cold.

Forth, that bottom "belly condenser" is a joke. Not only does it screw up the under car aerodynamics, drag on speed bumps, but it doesn't do much for heat exchanging either. I've seen those in person. It's clear they were not designed by an engineer. I could go on... but those aren't worth the time.

It's almost as bad as the "extra condenser next to the boiling hot cat converter" deal.

The only viable solution is to do a condenser in the front trunk where you could have large core area, top and bottom plenums, pulling air in from behind the front bumper, and exhausting out the bottom of the car via puller fans t hrough the hole left by the removal of the stock squril cage fan.

This setup would elminate the stock condenser at the deck lid as well.

Problem solved.

Problem created: No trunk area to store stuff

At least it would be fairly lightweight.


TonyG

Jastx

I have replaced my '89's rear condenser, all hoses, evaporator and drier with the latest cooling technology using a kit from Retroair.com. It gets charged tomorrow and Saturday. Can't wait for the results.

dbryant61

Tom, I just removed all AC components from my 1980 911SC. I have two components for sale that might fit into your repairs. I have a Sanden rotary compressor (with all necessary brackets) and the Griffiths center vent. email me at dbryant61@***.net if you are interested. Both are 3 years old and in excellent condition.

I rememoved my system because:

1. It would blow cold for only a day or two after a recharge. 26 year old hoses just could not hold a charge, and

2. I wanted to lose some car-weight for the track.

Don