Pre '86 A/C guys

[abetterkyle]

Wondering how the narrow vent guys have done with their A/C temps. I have a '78 and live in Oklahoma where its nice and hot/humid most of the time. Going to be re-installing the air conditioner as its just too damn miserable to drive 8 out of 12 months.

What all have you guys done to make it better besides the normal a/c compressor/condenser upgrade? dash swap? the vent bar added to the bottom of the dash?

[DaveMcKenz]

Wwest will tell you everything you need to know. From my standpoint the 84-89 systems need attention at several levels: heat exchange, air distribution, and refrigerant leakage. There are products and services to address each of these.
Good luck
Dave

[db_cooper]

On my 73 911 with factory A/C I installed a rotary compressor and ditched the piston compressor years ago. That alone improved the A/C performance and lessened the vibration with the compressor running.

On my 86 911 I installed a Kuehl Wirbelsturm (Hurricane) Evaporator Blower Motor from Griffiths..that helps a bunch too.

Lots of goodies for your 911 A/C

Griffiths supplies a range of air conditioning components for your Porsche 911,911s,911t,911 turbo, and 930, such as: Porsche air conditioning upgrades, Porsche air conditioning improvements and updates: Porsche barrier hoses and hose sets, Porsche c

[schoward]

I get 30's with a newer rotary compressor and R134a. I added the Kuehl vent center vent which helps but doesn't change the world.

It works ok as long I don't leave car to bake in sun prior to driving. Once everything is nuclear hot in car, the airflow just can't overcome it. If I park in shade and then start from that, generally it can do ok even in 90+ temps. Given I don't use the AC a ton, this is good enough for me.

If I were to go further (and had the system open), I would swap in a beefier condenser up front (easy swap) and perhaps add the Kuehl fan mentioned above. I like the Kuehl/Griffiths products.

[mlfox]

It's the 4th. season for this upgrade. Everything works well.

911Sc Air Conditioner Upgrade

Regards,
mlfox

[Arne2]

Did mine last year.

['84 Carrera] A/C re-work for mild climate

[GH85Carrera]

The Griffiths knee vents help. My Griffiths system keeps me nice and cool in the Oklahoma summer.

[SilberUrS6]

Originally Posted by DaveMcKenz

Wwest will tell you everything you need to know.

IFIFY. If you want cold vent temps, pretty much do none of the things wwest suggests, unless you enjoy throwing away money and time.

Barrier hoses. More airflow through evap. More evap capacity. Properly-charged system. If, after you have not spent all your money, upgrade the condenser(s) of your choice.

[tirwin]

Originally Posted by DaveMcKenz

Wwest will tell you everything you need to know.

Dave, were you being serious or funny? I'm going with funny.

[db_cooper]

I think the thing to remember is once you go to a modern A/C compressor, more robust evaporator/blower fan, bigger condensers and the extra vents..our 911s still have a hard time keeping the cabin cold in very hot weather..sadly in comparison a 10 year old Honda's A/C will super cool the cabin so you could hang meat safely.

Our 911s A/C was an afterthought in the design. We have an abundance of glass in a 911 which acts like a greenhouse and the A/C ventilation system is small and all up front near the driver/passenger..missing more than half the cabin area. Once the 911 cabin area is super heated in the sun..that dashboard, rear cabin, seats, deck, headliner area never cools down with the A/C running, even with all the best modifications. There is no real air exchange in the back of a 911. It's like having an baking oven door open behind you.

Best thing I did to help the A/C (once some of my other A/C mods were done) was some high U/V resistant ceramic tint on the rear glass, quarter windows and door glass. Hardly noticeable and it helps. Not a total cure though.

I think it is part of the charm of 911 ownership.

[GH85Carrera]

I drove my 85 911 with 100% stock AC for many years. It will keep you cool at night and on days below 85 degrees. It struggles when it gets close to 90.

My evaporator was filthy and needed to be replaced. No way to know that until the system is discharged and the evaporator removed.



This picture has made the rounds on the internet but it is one I took of my evaporator.

The real cure for the weak AC will cost you some money. Call Charlie Griffiths and talk to him about your car. He will quote you a price for a complete upgrade that really works. It ain't cheap but it is not difficult to install if you have any basic mechanical skills. The instructions he provides are the best you will ever see for any product. His support it top notch to match.

I have owned my 911 for 19 years. The AC upgrade to the system Charlie sold me is the best thing I ever did to my 911. It makes it a drivable car all summer. I drove to Monterey, California in June. Driving through Needles, CA it was 108. My AC struggled but I never got hot. Once the outside temp was below 95 I got cold and had to turn the AC temp up. That will never happen with stock AC.

Griffiths Technical Inc,Porsche Air Conditioning,Posche a/c upgrades,Porsche ac upadates,Porsche air conditioning upgrades,Porsche air conditioning updates,Porsche barrier hoses,Porsche compressors,Porsche condensers,Porsche condensors,Porsche receiv

[wwest]

Originally Posted by patssle

This is a random idea and a hypothetical question but I'm just curious if anybody has tried it. What if one pumped in more air through the heater cooling duct on the front of the engine? Could this make any impact on the cooling of the engine or is the airflow provided by the main cooling fan through the heads already at peak performance of removing heat?

Assuming we're talking air-cooled Porsches...

'83-88 models already have a "like" feature factory installed. The cabin heat control module has 2 extra sensors, engine oil temperature thermostatic switch, and speedometer input. If the engine temp begins to rise toward the RED zone, and the speedo indicates consistently low roadspeed, the cabin heater fan is activated to help cool the exhaust manifold thereby lowering the convection and radiant heating effects on the cylinder jugs.

There is a Pelican tech note (Bob Tindall? that points out that raising one of the heat control levers even so slightly, just enough to activate the heater fan/blower in the engine compartment.

With 83-88 911s that have A/C the third element in a trinary pressure switch can be used to activate the fan/blower to aid condenser efficiency in the same situation, improves rear lid condenser cooling airflow by almost 2X, more than 3X with an easy DIY mod to the blower inlet.

[wwest]

DIY engine cooling improvements, applied to my '78 Targa and my '88 Carrera (pictured).

Close off the engine fan bypass to the cabin heater fan/blower.


Notice the displacement between the fan/blower intake opening and the squirrel cage blower wheel edge. That's there to allow engine fan airflow to bypass the blower wheel.

Close that opening, maximum CFM of the blower improves by 30%


Plus you no longer have to endure the varying heat level with engine RPM.

[DaveMcKenz]

Funny. But he will tell you everything you need. No real need for anyone else to participate.
Dave

Quote de DaveMcKenz

Wwest will tell you everything you need to know.

Dave, were you being serious or funny? I'm going with funny.

[wwest]

Originally Posted by DaveMcKenz

Funny. But he will tell you everything you need. No real need for anyone else to participate.
Dave

Actually, no, I'm much better at telling you what you don't need!

[Bob Kontak]

Originally Posted by wwest

Actually, no, I'm much better at telling you what you don't need!

You have not contributed one iota of step change performance improvement value since you joined the board.

Don't you get that?

How can you not comprehend that you are regarded FULL-STOP within this forum as a buffoon?

[Ronnie's.930]

^^^ Come on now Bob - Wild West has warned us all of the evils of purchasing aftermarket a/c parts that actually make 911 systems blow cold (how dare they!), and opened our eyes to the fact that a friendly, knowledgeable a/c verteran's welcome, free advice (advice obviously meant only to frustrate the DIY types into further opening their wallets) should be disregarded due to his underlying "sell sell sell" agenda! I think we all owe the "Wild One" a heartfelt THANK YOU!!!

[wwest]

You are most welcome

[DaveMcKenz]

Wwest
Does this mod really work? Did you wire it to come on with a/c compressor clutch?
Thanks
Dave

DIY engine cooling improvements, applied to my '78 Targa and my '88 Carrera (pictured).



Close off the engine fan bypass to the cabin heater fan/blower.





Notice the displacement between the fan/blower intake opening and the squirrel cage blower wheel edge. That's there to allow engine fan airflow to bypass the blower wheel.



Close that opening, maximum CFM of the blower improves by 30%





Plus you no longer have to endure the varying heat level with engine RPM.

[wwest]

Originally Posted by DaveMcKenz

Wwest
Does this mod really work? Did you wire it to come on with a/c compressor clutch?
Thanks
Dave

Most definitely WORKS! Engine idle, ~800 RPM, 3X the cooling airflow over engine fan alone inclusive of the DIY blower inlet modification.

Red Dot trinary pressure switch, 71R7500, fan/louver switch element is used to power the cabin heat fan and the front lip condenser blower relay.

Activating the fans with clutch power does not allow the system pressure to rise to the level providing the most optimal heat transfer efficiency.

Currently trying to find a squirrel cage blower wheel that is as deep as the blower housing allows.