Air conditioner improvement kit?

[mlfox]

A/C season is coming to a close. I'm always looking for ways in the off season to make the A/C work better.

I found this "kit" on a competitor's website. It states that the kit bolts in and shortens the path that cold air has to travel and increases effectiveness by 50%.

What do you think these parts do, where in the 911SC's A/C system do you think they are installed, and most importantly, do you think it would make a difference?

Regards,
mlfox

[DRACO A5OG]

I dought it would work. But please try it and let us know.

Do you still have the bow tie diverter on penlum? If so remove it and it will flush the cab with cooled air instead of being diverted to the foot wells.

Jim

[widgeon13]

I don't think there is an easy way to improve A/C performance.

[fred cook]

Having done all the usuall upgrades, new condensers, new evaporator, barrier hoses, sanden compressor, pro cooler and underdash adjustable end vents, I too have been thinking about additional improvements. The under dash end vents work much better than the little "slot" that they replaced, but don't have as much air flow as I had hoped. I was in a Radio Shack store recently and found two 40 mm cpu cooling fans that I think can be fitted to the back of the end vents to boost air flow. They are 12 volt and are designed for a "constant on" situation so they should be realtively easy to install and wire. As soon as I get into the project I will add some pictures.

[wwest]

Originally Posted by widgeon13

I don't think there is an easy way to improve A/C performance.

Other than Porsche, I don't know that anyone has done a technical analysis of the early air cooled Porsche A/C's shortcomings. Since the front nose condensor and blower was added to later models I will assume that was the result of at least an elementary analysis by Porsche.

Building on that note it seems to me that the least expensive and most appropreate improvement would further Porsche's own effort.

My own basic analysis, poor man's analysis, measurements, indicated that as long as the evaporator itsself can be cooled via the continuous "arrival" of liquid refrigerant the Porsche 911 A/C performance is quite adequate. 1988 Carrera with tinted windows and in Seattle with no exceedingly HOT days.

2 modern thin 12 volt fans, <$50/Ebay, mounted on the inside of the engine lid to continuously "pull" high airflow volume through the rear lid condensor regardless of engine RPM.

Worked so well I was able to disable the front blower/fan. Leads me to suspect that the entire front condensor/fan assembly is now needless.

Long ago, many winter days back, with my '78 Targa, I learned that the rear heater fan/blower has a design flaw that REQUIRES high engine RPM for adequate heating in the wintertime. I used some thin metal sheeting to block the bypass of the engine airflow (when it even existed) around the squirrel cage blower wheel.

That bypass opening was making the squirrel cage blower horribly ineffective.

So I suspect Porsche's design flaw in both cases is based on their belief that the 911 engine will ALWAYS be operated at relatively HIGH RPM levels.

NOT...!!

http://www.ebay.com/itm/2X-7-12-VOLT-BLUE-SLIM-ELECTRIC-RACING-RADIATOR-FAN-?cmd=ViewItem&hash=item27bef883a3&item=170707682211&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr

[RSTarga]

The 964 air conditionor works great try Griffiths for early 911 improvements.

[mlfox]

Originally Posted by DRACO A5OG

Do you still have the bow tie diverter on penlum? If so remove it and it will flush the cab with cooled air instead of being diverted to the foot wells.

Jim

Jim,

I do have the Griffiths center vent installed at the bow tie area, and as you say, it does indeed help to flush the cab with the cooled air. The vent louvers allow some direction of the cooled air as well.

Regards,
mlfox

[mlfox]

Originally Posted by RSTarga

The 964 air conditionor works great try Griffiths for early 911 improvements.

Agreed! I just finished the second summer season since I installed Griffiths basic A/C upgrade kit (Sanden compressor, limit switch, & receiver dryer). With r134a, the cooling is acceptable even on the hottest Southern Indiana days.

Back to my original question... What are the purposes of the parts depicted in the first post's photo?

Regards,
mlfox

[Bob Kontak]

Originally Posted by mlfox

Back to my original question... What are the purposes of the parts depicted in the first post's photo?

Did you contact the competitor and ask them what the ricer muffler tips were for?

You live in Indiana. That is the North Pole relative to Fred Cook. You should have NO A/C issues (I mean NONE) if the factory setup is working correctly.

[mlfox]

Originally Posted by Bob Kontak

Did you contact the competitor and ask them what the ricer muffler tips were for?

You live in Indiana. That is the North Pole relative to Fred Cook. You should have NO A/C issues (I mean NONE) if the factory setup is working correctly.

Actually, no, I have not asked them yet. I'm hoping someone will at least speculate on the pictured parts and their intended uses.

As I stated earlier, the A/C, with the Griffiths upgrade, is indeed acceptable for the hot season here. When the system is properly charged, the center vent temps are consistently mid 40's on the hottest days. Certainly not "Walter P. Chrysler" cold, but cool, dry, and comfortable. I'm satisfied with the results of the upgrade but always looking for better ways.

I have other work to do on the system however, i.e. replacement of the original hoses with the barrier type. I am considering adding outboard vents that are like the vent I added from the bow tie. Now that I think about it, I wonder if that is what the "ricer tips" are for.. to block off the duct that the side vent flex tubes are connected to?

Regards,
mlfox

Regards,
mlfox

[Bob Kontak]

R12 or R134?

I put Griffith's Tech's Sanden Compressor and barrier hose on the low pressure side and the compressor to engine lid condenser hose back in 1997.

The barrier hose was a "new" product for them back then and the price was - introductory - a beta testing price of $50-ish. Damn, I wish I had bought the high pressure side hoses at the introductory price.

Edit - Recently replaced R/D and expansion valve, purged and re-filled with R-12 after sucking a healthy vacuum with Robinaire equipment for 12 hours. I bought a 30 pound tank of DuPont Igloo R-12 with my MACS 609 card and my buddy (has an older 911 too) has the gauges and vacuum equipment. We figure we are both set for a decade.

I do not have the G Tech center vent. I have essentially two holes/short tubes coming from the bulk-head and that is it. My right shin freezes but with the recent refurbish and R-12 topped off (and with sealing off the evaporator assembly from air leaks) I can feel cold air being pushed between the top of the seats with my hand. Big improvement but I still need what you have - the vent distributor.

What I would do is read what wwest has to say re: the condenser fans. He is in a similar temp band as us and, although, on the west coast and probably wears clogs, he seems pretty ok. I believe that is the best bang for the buck you and I could install.

[mlfox]

Originally Posted by wwest

2 modern thin 12 volt fans, <$50/Ebay, mounted on the inside of the engine lid to continuously "pull" high airflow volume through the rear lid condensor regardless of engine RPM.

Worked so well I was able to disable the front blower/fan. Leads me to suspect that the entire front condensor/fan assembly is now needless.

2X 7" 12 VOLT BLUE SLIM ELECTRIC RACING RADIATOR FAN | eBay

Interesting... how did you wire the fans, how did you mount them, and were there any issues with clearance?

Regards,
mlfox

[mlfox]

Originally Posted by Bob Kontak

R12 or R134?

r134a

Regards,
mlfox

[Bob Kontak]

Originally Posted by mlfox

r134a

Doooood - we can get that problem straightened right out. You are just a few hours from me.

[wwest]

Originally Posted by wwest

Other than Porsche, I don't know that anyone has done a technical analysis of the early air cooled Porsche A/C's shortcomings. Since the front nose condensor and blower was added to later models I will assume that was the result of at least an elementary analysis by Porsche.

Building on that note it seems to me that the least expensive and most appropreate improvement would further Porsche's own effort.

My own basic analysis, poor man's analysis, measurements, indicated that as long as the evaporator itsself can be cooled via the continuous "arrival" of liquid refrigerant the Porsche 911 A/C performance is quite adequate. 1988 Carrera with tinted windows and in Seattle with no exceedingly HOT days.

2 modern thin 12 volt fans, <$50/Ebay, mounted on the inside of the engine lid to continuously "pull" high airflow volume through the rear lid condensor regardless of engine RPM.

Worked so well I was able to disable the front blower/fan. Leads me to suspect that the entire front condensor/fan assembly is now needless.

Long ago, many winter days back, with my '78 Targa, I learned that the rear heater fan/blower has a design flaw that REQUIRES high engine RPM for adequate heating in the wintertime. I used some thin metal sheeting to block the bypass of the engine airflow (when it even existed) around the squirrel cage blower wheel.

That bypass opening was making the squirrel cage blower horribly ineffective.

So I suspect Porsche's design flaw in both cases is based on their belief that the 911 engine will ALWAYS be operated at relatively HIGH RPM levels.

NOT...!!

2X 7" 12 VOLT BLUE SLIM ELECTRIC RACING RADIATOR FAN | eBay

Originally Posted by mlfox

Interesting... how did you wire the fans, how did you mount them, and were there any issues with clearance?

Regards,
mlfox

Space...'88, no problem, '78, not so easy, mounted under the rear spoiler, "pushing". '88, mounted on the under side of the condensor using the supplied kit. Fans run in series, 6 volts each, with the A/C on/enabled, in parallel with the compressor clutch engaged.

I'm considering the addition of the binary switch, disables Compressor clutch if refrigerant pressure is too low, <30PSI, low refrigerant charge, or too high, 350PSI.

[wwest]

Originally Posted by mlfox

A/C season is coming to a close. I'm always looking for ways in the off season to make the A/C work better.

I found this "kit" on a competitor's website. It states that the kit bolts in and shortens the path that cold air has to travel and increases effectiveness by 50%.

What do you think these parts do, where in the 911SC's A/C system do you think they are installed, and most importantly, do you think it would make a difference?

Regards,
mlfox

I would guess that the 5 "nozzles" are to replace the factory ones which are a bit restrictive to airflow. They are only for heating mode, footwell outflow, and you can simply remove the factory nozzles, no need for these.

Would it make a difference...only in your, their, dreams.