My '78 Targa has a rear spoiler so the fans can be mounted on top of the engine lid under the spoiler. my '88 Carrera has a different intake setup so the fans are inside the engine compartment.

Don't really know about your '83 but you may be able to find fans thin enough to fit. It is needless to have fan diameters larger than the front to back dimension of the condenser. 2 fans mounted nearest the HOT side, compressor output, should suffice.

The real issue with the fans solution is dumping all that extra hot air in your engine bay anywhere where ambients are over 90 degrees. probably works fine in seattle.
i tried that in houston, and my engine temps went up almost 30 degrees... no other changes... seriously.. so I went with a fender mounted condenser with fans.
just saying... one size does not fit all...

Porsche never designed early 911s body design for A/C; it was a complete afterthought trying to appease 911 owners in the US market that demanded A/C

Early 911s A/C using old technology tube and fin condensers greatly suffer from a lack of enough condenser surface area to be efficient; this is why these 911s have so much trouble making COLD A/C!!! This unfortunate problem is well known!!!

FYI it is my proven opinion from my own extensive testing, additional rear fans ONLY, are not the answer to making 911s cold with stock condensers; they will however help for stop and go driving when engine speed drops down under 2000 RPM and at idle

a 911 engine in the engine compartment has ONE BIG ENGINE DRIVEN FAN THAT SUCKS A TON OF AIR CFM ; if you take advantage of this BIG FAN YOU ALREADY HAVE & completely seal the rear condenser to the deck lid and force all the incoming deck lid air THROUGH THE READ CONDENSER is all you need in the REAR

the front condenser could greatly benefit with additional fans for stop and go driving & at idle car stopped; or the air-vent temps will begin to rise during these times

believe it or don’t

http://forums.pelicanparts.com/uploa...1333111648.jpg

36 degrees F @ 81 F ambient achieved 3-28 2012 on a 911 RSA using only rear engine fan and completly sealed to the deck lid rear PFC; and the front PFC with no fans, but placed to take advantage of only front air movement with car forward and no front fan & using stock OEM evaporator

http://forums.pelicanparts.com/porsche-911-technical-forum/617196-i-make-parallel-flow-micro-channel-condensers-911s-front-rear-13.html

South florida is a truly tropical humid climate
 

I live near the Atlantic Ocean in Fort Lauderdale in South Florida, the climate down here in South Florida & north from about 50 miles north above Palm Beach and then to the South to Southern Most portion of the continental point of the USA Key West ; IS A TRULY TROPICAL HUMID CLIMATE and “south Florida is the only tropical climate in the continental USA”, due to its proximity to the equator; The temperature here, because it is tropical is never extreme hi temps and in Central and northern Florida where it IS NOT TROPICAL gets much hotter ;

However here in August and September for example temp max is usually about 92 F degrees or so, and is this way sometimes both day night for 24 hour periods, and I have seen it this way for several weeks at a time. NOTE: Last summer we had an all time record here; Fort Lauderdale’s hottest temperature reading in 2011 was 97 degrees registered on July 17th; and during this heat wave I was getting constant vent temps down to 31-34 F

But when it's 92 F degrees here and 100 % humidity mix together which often happens here OUR HEAT INDEX temp goes to What “the temperature feels like to your body: to be 142.8 degrees Fahrenheit / 61.6 Celsius”

Furthermore as if this weren’t bad enough on your body here in the tropics at only 92 F with high humidity what the heat index makes you feel like in this situation; with high humidity evaporation in your evaporator at only 92F the Efficiency in your A/C system drops proportionally and becomes more difficult TO MAKE COLD!

If you want to figure/calculate WX HEAT INDEX temps go here Heat Index Calculator

Sometimes Unknowing People related to A/C in the Mohave desert i.e. Arizona, New Mexico, Nevada, etc. crack me up telling me their high temps between 105-120 F or so, & it’s not hot here compared to where they live their HEAT INDEX temps are the same as their temperature due to desert lack of or very low humidity my Aug & Supt. HEAT INDEX temps can sit at 142.8 degrees Fahrenheit

Anyway humidity and warmer or hot temps greatly tax any A/C system ability to make cold and greatly overworks them attempting to keep up, causes Efficiency to drop on all the component plus can lead to early failure. I hope this helps to answer your question; I am sure others will chime in.

to let people simply know that you do not need to spend a ton of money on your 911 to make your A/C system cold

The TRUTH IS THAT Any 911 owner by just simply replacing their old 911 Porsche OEM old tube and fin type obsolete technology condensers to much newer technology state of the art parallel flow micro channel condensers front and rear you will reap a vast improvement in greatly lowered a/c air vent temps and making your 911 cold.

Changing to serpentine technology condensers, which offers only a slight improvement over tube and fin technology, has been indisputably proven to be rendered in today’s world old-fashioned technology worldwide; by the invention and introduction of (PFC’s) Parallel Flow in Micro-Channel heat exchangers in 2003. If you don’t believe go look at any of the world’s major industrial or residential web sites and do some reading. I have taken this to a higher level of efficiency in my opinion for 911 state of the art PFC's

THESE ARE FACTS!

Spending a lot of your hard earned money Changing your A/C components, i.e. hoses, evaporator and/or your compressor if they “currently ALL WORK PROPERLY as originally designed”, although replacing these components might give limited improvement to your 911, regardless to what anyone might tell you “these things do not need to be replaced” they can continue to be used!!!

My successful extensive testing proved this last year repeatedly getting constant, just about freezing 34-36 F ice cold vent temps in all kinds of driving conditions (without evap icing) , even during 95F degree ambient temps in 99 % humidity heat index of 160 F / 71 C , where I live in THE TROPICS of Fort Lauderdale

However these stated very low temps were reached by using a succession of several different component optimizations and well known 911 A/C tricks

I manufacture custom made new technology PF condensers; I am not trying to sell anything here I am trying to be helpful to 911 owners!!!
I will make my PFC’s available here at Pelican very soon to the public

Reid,

Sorry dude. You crossed the line, and you are not factual.
Most readers on the forum know better however you have posted some opinions which could confuse a newbie and lead them down the wrong path.

“Porsche 911 A/C CONDENSER Efficiency! IS the best key to making COLD A/C!
Everything Else is secondary !!!
That is like saying bigger tires are better, and forget about the rest of the suspension.

“I also have done test differences of Griffiths serpentine evap.”
And, your own empirical data ?

“A Modified (TX) Thermal Expansion Valve"
And the data of superheat difference and how it was arrived at?


“Changing to serpentine technology condensers, which offers only a slight improvement over tube and fin technology”. WRONG.
The performance of any condenser is related to its overall characteristics to remove the heat. Simply having more channels, multiple circuits (paths), thinner walls, whether the design is tube and fin, serpentine, multi-pass serpentine, piccolo, 6mm piccolo, parallel flow, multi-flow or the latest and greatest 11 mm wide micro-channel mult-pass parallel flow does not make it an improvement if the overall system is not optimized. There are plenty of studies that show
there is a limit to the maximum performance of PF condensers vs. serpentine, in some applications a PF will perform better, however if its going to be in a place where things "shake, rattle and roll", it won't last long. So its NOT all about about wishful performance. It does not make sense to have the highest performance gadget if it breaks down on you in the middle of no where. This would be like tightening down the spring on the waste gate and failing to address AFR’s and strength of the lower end. Of all the condenser designs that have come to pass the serpentine design is the most reliable due to its wall thickness and least amount of brazed joints. I have seen more parallel flow condensers, as well as evaporators sharing the design (plate and fin), as introduced with the Boxster and 996, fail simply because the walls are too thin, making them subject to leakage due to oxidation , and breakage due to the greater number of braze joints. The key to a successful product is not simply newer technology, rather its selection of the correct technology for the application. And, on a side note: if you are rationalizing that all car manufacturer's have switched from either tube and fin, or serpentine to PF's simply because there is a gain in performance ? Think again. The cost produce PF's is less, for 2 reasons: a change in manufacturing techniques and less materials.
The car manufacturer knows the new car owner will not be keeping that car forever: most vehicles today are leased or sold within a few years, so overall "life" or reliability of the PF is not a priority. Cost is their priority.


“Changing your A/C components, i.e. hoses, evaporator and/or your compressor if they “currently ALL WORK PROPERLY as originally designed”, regardless to what anyone might tell you “these things do not need to be replaced” they can continue to be used!!!” WRONG.
The 911 and 930 have nearly 40 feet of non-barrier hose. The hoses leaked (permeated) the day they rolled off the ‘hand built’ assembly line, and after 20 years the leakage rate is not less. If a car owner wants to recharge his system every other month or year and that becomes a bugaboo then the logical solution is to replace all the hoses with barrier hoses.

And, since they plated the steel hose fittings with zinc, and zinc oxidizes and accelerates the formation of rust on steel, you might as well replace all the o-rings since they degrade with the process, and you might as well use a an HNBR R134a compatible elastomer.

The systems prior to the 964 did not have a low or high pressure switch to protect the system, so you might as well add the feature when you repair or upgrade the system to help protect the compressor.

You should replace the drier if its old or your are changing to a different type of refrigerant oil.

The early 911/930 had insufficient vents, you might as well add more.

A 25 year old evaporator typically does need to have is fins cleaned and if you have an 86+ evaporator chances are 9 out of 10 if its not leaking now it will be soon because the design used to bond a copper manifold to aluminum tubes simply did not work (wander over to the 928 forum and read about evaporator failure), so you might as well replace the failure-prone or old evaporator with something smarter in design and performance such as a serpentine unit, does not make sense to spend time and money improving the condenser function while not addressing the other side of the system.

Using a compressor with aluminum bores, aluminum pistons and aluminum wobble plate with 80,000 plus miles on it, which has run for 20 years with low refrigerant/oil levels, is going to ‘grenade’, ‘lock-up’, ‘freeze’, and fall apart as soon as you start using it with your new parallel flow condenser, at which point you will have to remove half of the hoses in the car, remove the evaporator and disassemble the TEV, liquid flush the lines, toss the drier, and liquid flush the tube and fin or serpentine condensers. If you have a parallel flow condenser you might as well toss that out too simply because studies have stated they are extremely difficult to flush out (forget about the in line filter, its been discussed).

While your working on the evaporator and your wiggling the thermostatic sensor tube for its hundredth time, and it breaks, your system won’t operate. While your taking that long awaited vacation trip cross country, and the evaporator blower or front condenser blower motor (which still may be lacking a fuse) motor fries up, who you gonna call? So... “... not Spending a lot of your hard earned money (or time) and Changing your A/C components”, is what?


“However these stated very low temps were reached by using a succession of several different component optimizations and well known 911 A/C tricks”.
I won’t get into the oxymoron, but if your objective in this thread is to deliver a simple solution (just a condenser) to a client then there is no “trick”. The fundamentals of refrigeration and heat transfer are not secrets.


“I am not trying to sell anything here ...... I will make my PFC’s available here at Pelican very soon to the public”
OK. I think that’s great. But, stick to the facts.

^^^^^ +1 ^^^^^

One of the few A/C Experts on this forum who earns his reputation daily has spoken. We are all vulnerable to the opinions expressed by others that may not be factual and in some cases flat out wrong. Thanks Griff for pointing out to us non-A/C professionals what's what and, more importantly, what's not! :)

kuehl respectfully my post statement were very specifically geared to those 911 owners who in this terrible economy & trying to feed their families etc., with so many millions out of work that have very limited cash flow and cannot afford to spend several thousand dollars to make their a/c work at least good enough so they are not miserable sweating in the heat when driving their 911 until they can afford to spend more later.


Have some compassion for those that are financially struggling in this economy !!!
Under this premise I believe what I said is valid!
Sure there is much more that is needed to be done to enhance someone’s 911 a/c system to get “really good a/c temps”, but I stand by what I said that a person with very limited budget and money who’s 911 a/c system is still all original and everything at least works and is in good order doing what I stated, with some proper cleaning & preventative a/c maintenance and a few additional 911 a/c tricks could get by quite nicely for now until they can afford to make their a/c system better then it is currently and/also for those on a tight budget that will need to upgrade the a/c system a step at a time to make it better and leading to making it optimum.

You and I have a different concept related to a/c systems sometimes, you are making big money selling your products which is fine but I think you may have forgotten the people that are unable to spend several thousand dollars and I care about these people that need to be told the truth for what is best for them to get by with until better times.

I completely disagree with you regarding serpentine a/c components verses Parallel Flow Technologies, and so does all the major automotive manufactures of the world or they would have never switched away from it like they did, and I hope you keep your mind set regarding serpentine as it makes what I hope will remain friendly completion more interesting; As I consider serpentine to be obsolete technology that you are sold on because you have a vested interest in/or mindset in or whatever.

I have gone out of my way to be respectful to not focus on the serpentine technology you are using and been very careful not to put it in your face out of respect for you as you just did to me!

I don’t have time at the moment to go step by step with your serpentine argument you are keen to protect and argue with you, but if you like I will when I have more time, as I am as adamant about my PFC technology as you are for your serpentine technology.

But for now I will say this, I am not buying most of your arguments, I am a marine engineer and have 30 years working in a marine environment related to all kinds of metallurgy damage that was subjected to far more than anything you have ever witnessed on land in the automotive or air conditioning industry, furthermore I have read i.e hundred of scientific studies that compared all types of condensers as well as aluminum PF condensers and multitude of other heat exchangers, and could probably fill up several long desktops of studies related to PF condensers.

Best regards always

Folks under that kind of financial strain probably shouldn't be using 911s as daily drivers. And if they do, selling them a condenser is not going to change the leakage of refrigerant from old hoses.

No matter how often you change your tack, the wind is still going to be in your face here.

Let's face facts, Reid - your marketing efforts are not going to overcome your skeptics. Including those of us with a science education who demand data, and not platitudes and emotional appeals.

Give us your testing data and your testing conditions, and let the real facts speak for themselves.

And for the love of Ferry, PLEASE stop posting the same post in 4 different threads.

buy a 964

Would you rather change an evaporator in a 964 or a 911?