After sinking a bunch of $$$ and still only getting warm tepid air out of Porsche's system this idea keeps looking better...>http://forums.pelicanparts.com/uploa...1332856617.jpg

I would like to dispute the 'R-12 is a better refrigerant than 134' with all due respect... while this may be true from a thermodynamic efficiency point of view, I think the better components available today (compressors, expansion valves, evap's and condensors) far outweigh this difference. Get in any new car these days, turn the A/C on high and try to keep your hand near the vent without freezing it; I don't recall too many old cars with A/C this good.

I put the renn-air system in my 911 a few years ago, and it rocks.. I suspect any of the conversions mentioned above would be an awesome improvement that anyone will enjoy.

Hope this helps,
Chuck.H
'89 TurboLookTarga, 332k miles

1994 RSA with earlier 1973 retro look & style for fiber body kit RETRO-FIT PROTOTYPE
 

http://forums.pelicanparts.com/uploa...1332857892.jpg
NOTE: FULLY SEALED AIR-INTAKE TO THE COUNTOUR PFC


http://forums.pelicanparts.com/uploa...1332858015.jpg

NOTE: STEEL 911 OEM DECKLIDS DO NOT NEED THESE ADDITIONAL SPECIAL MOUNTING METAL CLIPS & BRACKETS THIS RSA RETRO FIBER DOES:

HINT: dump your old OEM condensers and UPDATE your condensers to newer technology

You did something wrong. When the factory systems work there is cold air. It is a mediocre system at best, but is tolerable (at least for me) in the northern states. I say that but do have a Sanden rotary compressor bought from Griffiths Tech (and low side barrier hose) but that is it. No other updates.

"...The NEW KID ON THE BLOCK..." needs an education on "KISS"

KEEP IT SIMPLE.....STUPID!!

As you so correctly point out, the only thing wrong with the factory A/C system is the lack of condensor heat exchange efficiency. That lack can be more than made up for via providing a high level of airflow through the rear lid condensor even with the engine RPM low.

A pair of 12 volt fans for less than $50 will do that quite nicely.

Install a pair of these fans and you can even disable the horribly inefficient front condensor fans.

http://forums.pelicanparts.com/uploa...1332870396.jpg

wwest - I will bite on those. Do you have a link or a brand name to that set or will any set of fans like this work?

Summit Racing is nearby (Akron is Summit County) and they have lots of these fans on display.

Moving from the old-style tube/fin condensers to more-modern serpentine units can also increase efficiency. Getting the cold air into the cabin by upgrading the evaporator and evaporator fan, and preventing leaks by moving to barrier hoses - all these things will help the original system work acceptably. Some folks have gone far enough that they can store meat inside during the heat of summer - but that's just bragging. If you can remain comfortable in your particular climate, then that's "far enough", without resorting to any gimmicks. Moving air across a condenser is important. But if you move air faster than the moving air can pick up the waste heat from the condenser, then you are not being efficient in your heat transfer. Airflow has to be matched to heat transfer. That's why sometimes the vent temperatures are lower on lower fan settings than higher ones - a specific fan speed is matched with the evaporator heat transfer capability, and the two work together to provide the lowest vent temps.

In any case, popping for expensive, unknown-reliability custom condensers is not within the realm of the K.I.S.S. principle. Stick with proven designs backed with warranties and satisfied customers in a reasonably large installed base.

As I know absolutely nothing about how A/C works (except the flow of the refrigerant and what I've read), I need to do a lot of research before I fork out any money - and the amount of money to be forked out is definitely part of the equation. Where I live it is more humid than hot, but put the two together and add black on black 911, and it's a sauna to say the least. Is there a better version based on humid air vs dry air? I've read several posts about the challenges of humidity vs dry and how hard the system has to work. I don't have a rear stock condenser at this point either, so I'm not really tied to any specific solution or timeline even.

The more robust the system the better it will be at handling humidity.

If I had the discretionary funds and was buying new, I would:

1. Buy the rear KelogGes unit
2. Get the compressor Griffith's Tech recommends
3. Install the fans wwest mentions
4. Install the upgraded evap fan
5. Barrier hoses (these will pinch a little $$)
6. New O-rings if applicable and new receiver dryer (mandatory)
7. Flush evap and front condenser as well as remaining hoses. If you are awash in cash, upgrade these but I would not if you do 1 & 3 above
8 Replace your expansion valve (because they are cheap)

Consider keeping R12. I do not know what the laws are in Canada but it is easy to get R12 in the US with the online MACS 609 certification. Not as easy as driving to Walmart but very do-able.

Get some gauges, a vacuum pump and some mineral oil and get down with your bad self to wrenching. The only non factory hard pieces would be the rear condenser, hoses at your discretion, fans and the new compressor.

Bob,

Couple of additional questions:

(1) When you say new dryer - would you install the Renn-Aire ProCooler in lieu?
(2) How do you flush these parts - is that what the mineral oil is for - definitely outside my comfort zone/knowledge base?
(3) How do you mount the fans on the rear deckled condenser? Can't screw through it.
(4) Upgrade of evaporator fan - Griffiths one?

Thanks.

I don't know all the answers, it is probably best to ask Griff.

However:
- new dryer is a must & they are not expensive. Every time you open the system moisture gets in and unless you bind it you could have the system freeze.

- not sure how to flush, there are a few threads on that. I think the best method involves a flush gun and pressure. The oil is probably more what you need to keep the compressor lubricated. Mineral oil for R12, PAG for R134.

- my desklid has the brackets. you can see how that works on KelogGes' picture. you are actually not bolting through the deckid, it's not a single piece of sheet metal. ;)

- i got Griff's fan but still need to install it, so fcan;t tell you how good it is at this point.

I bought mine on Ebay.

1. If it drops vent temps 20% it is worth the price delta of a wee bit over $200. That's only $3 Canadian. :-) My system cranks out a chilly (not) 50-55F at the vent. 20% is ten degrees. That is a huge increment.

2. I used mineral spirits and the (dry) air has to flow through there for quite a while to dry it completely. A high quality vacuum pump will probably assist in evacuating add'l spirits remaining but I do not know what the vacuum would have to be to vaporize it. An option is to dismount the units and pay for professional purging and pressure testing. There are products that will dry faster at a price. Mineral spirits and mineral oil is dirt cheap. Mineral oil is distributed among the parts before you button up the system. Couple ounces here and there. I can find the exact amounts when you are ready.

3. I will know within a month or so because I like the idea. I will drill into the inner deck lid without reservation. Used deck lids can be purchased for cheap so these are not on the endangered species list.

4. Yes, the Griffith's one. I had some evap box sealing issues and my factory fan can now pump air to where it can be felt between the top of the two seats from the bulkhead vent. Pretty anemic even when working well. OK for northern Ohio but that is what, three and a half feet? Also the increased air flow will strip more anti-therms from the evap delivering more cold where you need it.

The Renn Air barrier hose price is not too bad- $300. R134 will sneak out faster than R12.

FYI - I think I have a used 3.2 Carrera condenser I bought cheap off of ebay in my attic. The ad said it would fit an SC but the fittings are different. I paid maybe $25 for it. It's yours for postage.

Thanks - That is what I needed to hear. Summit would be full retail and I have two-three months here before the real heat kicks in.

Bob,

PM Sent

.....

How would the two fans on the rear deck be wired? You mention they would kick in during compressor operation only?

Here's a site that appears to have similar fans for info.

2x UNIVERSAL 12" 12V RED PULL RADIATOR FAN - Radiator Fans - Radiator HK5 Motors

or perhaps the 7" or 9" versions - what sizes would be best for the max flow across the condenser?

To wwest
 

I have a '83 SC Coupe, standard engine lid, no tail. Would there be sufficient clearance to mount these fans with my set up? It would seem that the air cleaner snorkel cover would limit space to mount the fans.

wwest: How are yours mounted? Could you please provide a pic of the mountings and how to wire them?

Regards,
mlfox