Aircon on 944

[bteoh]

Hi,

I have a 1984 944 2.5L and just had the aircon regassed. It was first pressure tested and appeared to hold pressure. 134a was added - approximately 850grams but the central vents were only getting temps around 15 degrees. Hi-Cool additive was added which brought the temp down to about 12 degrees. I don’t know if that is normal for the factory aircon but it doesn’t seem super cool. Would like to know what other owners experience in their cars?

Cheers

 

[Coastr]

Rather than vent temps, is it cooling the cabin effectively?

vent temps can be deceptive.

[TINGY]

My A/C guy always does vent temps and the last couple of times i have had him do mine the temps were around 3-4 degrees, not sure he puts in a specified amount of gas though and leaves it at that, there is always an amount of fine tuning that he does and it's only ever one type of gas.

[bteoh]

Perhaps the Turbo and Series 2 944s have better vent designs and fan motors? The earlier ones don't seem to be super efficient and I wonder if any owners with the earlier 944s have problems with their cooling. I reckon in 40 degree days, mine would struggle to cool the cabin effectively.

[Buchanan Automotive]

Australian Delivered 944 2.5L NA ( 1982-1984) manual trans & auto trans could have three completely different A/C systems & then there was differences again in relation to one particular system over three years, two of the systems were poor to say the least and the other was barely OK 

But why I hear you ask ? 

Simple it was all to do with Taxation and nothing else , in or around 1981 the Australian government bought in some very innovative / draconian TAX threshold where a car that was over a certain limit ( I think from memory it was in the low $ 40,000's , maybe $45,000 at most ) , any car over this limit was taxed in lots of new ways & it was this limit that Porsche with their 944 , Mercedes , Volvo , BMW with their cars that were on this threshold did what they could to de option the car to be within $ 100 under the limit , I know because I was at a Porsche dealership in Sydney at the time and you could see what this meant 

Naturally the 911 series and the 928 series were way above this limit , so they just attracted the heavier taxes ( can remember what they were called ) and that was that , but the 1982 - 1984 944 was very much effected & Porsche Cars Australia did everything they could to get the cars in and on the road under the limit , it sells more cars 

The first thing to disappear ( not ordered ) was factory A/C in R/H/D , it was very expensive , but you pay for what you get in most cases , so Porsche cars Australia awarded a contract to a company in Melb called Air International and they installed a custom system to the 944 ( 1982 - 1984 ) , the quickest way to see if its was one of these was they had a custom steel bracket made to mount the non N/D A/C compressor ( much cheaper compressor was chosen ) , where as the factory A/C ( 1982-1984) the the super expensive 928 N/D A/C compressor with a different A/C clutch just for the early 944 and magnificent cast alloy ( hollow ) master bracket that secures the large compressor & alternator to the engine , the Air International also had a custom under dash evap unit that lived under the dash on the passenger side , also the A/C hoses were cheaper & the condenser was a lot cheaper , it was OK "ish" when new , but it had issues , 35 years later , no hope 

  There were a few ( 6 or 10 ) 1982 944 cars that did have the factory fitted R/H/D only A/C , these were rare because this very expensive option pushed the price of the car way over the TAX limit and the car attracted more taxes , so this was not popular 

Factory A/C became standard on the 1985 944 along with power steering in R/H/D , by 1985 the cars were over the TAX limit anyway so they just optioned them up to attract another more well heeled customer , the factory system was good in some ways but it still had some flaws , many the remote fitted Avap unit behind the floor board on the passengers side ( way less leg room but worse still like on the same year versions of the 911 , the remote evap had to send what cold air it could through a fabric tube to the tiny cente vent 

(1986 onwards  )  the entire interior was scrapped and Porsche started again and spent a fortune , they even got ND of Japan to design  and build the best climate control systems ever fitted to a Porsche ( ever ) , but thats another story 

Note } I am amazed the A/C even works in a 1984 at all , 34/35 years later , you can make it better , first thing is its most likely not shedding heat , you need 2 rad fans working at the same time( if you have one it will not work & they must run while the A/C is cycling)  & if the old serpentine condenser is still there then there is 70 % of the problem , hence why we have been fitting Parallel flow condensers in the 944 series for years & years & years 

Regards

Bruce Buchanan
Buchanan Automotive
41 years working on Porsche cars 

[Ross B]

Interesting info Bruce.

Factory A/C became standard on the 1985 944 along with power steering in R/H/D , by 1985 the cars were over the TAX limit anyway so they just optioned them up to attract another more well heeled customer , the factory system was good in some ways but it still had some flaws , many the remote fitted Avap unit behind the floor board on the passengers side ( way less leg room but worse still like on the same year versions of the 911 , the remote evap had to send what cold air it could through a fabric tube to the tiny cente vent 

I have a 1985.1 car that arrived in Melbourne in Jan 1985. The aircon is very average with temps above 35 degs here in Queensland, even having had the compressor rebuilt for the modern gas, and a new condensor (imported from the USA) fitted. The evaporator is mounted in the passenger footwell and my aircon only delivers cool air from the centre dashboard vents and not from the side dashboard vents, and I thought this must be an issue with my car. From your comment above all 1985 cars do. 

Ross 

[Buchanan Automotive]

Hi Ross , all quite normal , in fact I am amazed it still works at all because its very unusual to have a European made car ( any ) that like in this case has A/C from the 1970's that is still working today ( at any level ) & this ancient system was never intended for 35 deg cel

What I mean by 1970's is that the system in you're 1985 944 ( last of the series 1 , 944 ) was literally from the mid to late 1970' s , but the remote evaporator unit ( just like on the same year type 911 ) was from the late 1960's / very early 1970's Euro A/C design , meaning by today's standards in A/C remote evap unit and its silly fabric air hose etc is almost "cottage " or quaint

Note } the above is not  criticism  for the sake of it , I am just pointing reality of this early era A/C that was truly an afterthought as compared to the fantastic climate control / A/C system that was fitted by Porsche in the 944 2.5L NA ( oval dash ) 1986>   , 951 , 944S , 944S2 , 968

Regards
Bruce Buchanan
Buchanan Automotive

[Ross B]

Bruce My 1985.1 also has the aircon control knob with the cimbined on/off, fan speed and temp control. When the knob is rotated clockwise from the 12 o'clock position it switches on the compressor then as you keep turning clockwise the temp drops (in theory) until the  clockwise rotation stops at about 11 o'clock. What had me stumped was how to vary the fan speed, and Ted from T&D Brisbane enlightened me that you pull the knob out! There are 3 distinct knotches 1 being the low speed and 3 being the high speed. 

As you would know this is quite a complex switch with capillary tubes and temp sensors hanging off the back of it.

About 3 years ago when I was gathering up parts for the car that I thought were particular to it and may not be readily available in the future, I bought a spare replacement aircon switch to have on hand. At the time it cost me about AU$350-$400 and Porsche at that time only had 3 left in stock worldwide. At the time I couldn't determine whether it had been used by other car makers.

Bruce do you know if these switches were used in any other vehicles of that time?

 An aircon guru once told me the inefficiency of the early A/C systems was not only caused by the poor design elements you mention, but by the fans as well. The early A/C used the heater fans of the era that were available, these low velocity fans were good for pushing warn air around the car but hopelessly underpowered to push the cold air in sufficient quantities that was required to cool the interior of the vehicle. 

Ross

 

[Buchanan Automotive]

Hi Ross , yes the large Rotary (black with a blue trace )  was a factory thing only & it took the place of the middle center console instrument gauge , so in other words the same 944 with NO A/C had three gauges in the center console 

Now this large rotary switch which is a in essence an adjustable evap switch ( capillary tube ) and a fan switch ( pull out three speed ) its quite complex but remarkable robust & no I do not know of another car maker using it

Note } some of the Non Factory A/C systems fitted by Air International in 1984 used the expensive Porsche only rotatory switch  , this confuses the crap out of people because they think , Oh this must be the factory A/C system = wrong , so its all quite confusing and it was all caused by our TAX system

Now we come to the advice you got about the interior fan , I nearly fell of my chair laughing , the poor guy was talking about some other car , now you're car has a pair of relays that when NEW and working correctly , if you had the normal heater /demist ventilation fan on & then turned the A/C switch on , the relays worked in conjunction with the A/C switch ( input ) and it would automatically turn the normal heater fan off ( all by its self )  , that means the normal heater demist ventilation fan has Nothing At All to do with the A/C air distribution or speed .

Now lets go back a step , you car has a remote , (meaning not inside the heater box ) A/C evaporator unit with its own evaporator fan and motor , this fan /motor pushes ambient air through the cold evaporator ( now cold hopefully ) and this air is now on its way through the hopeless non insulated fabric tube up to the center vent ( way too small )  , the size of the evaporator / A/C air speed fan and motor can & is very 1970's , it is what it is & it was OK "ish" for the 1970's , because that's all there was

Thats why Porsche had to modernize the 944 ( 1986> ) because they knew full well they just could not keep on selling this 1970 stuff , in 1985 ( back at the Porsche dealership I was at ) we had customers complaining about their expensive factory A/C on hot day ( 911 & 944 )   and this was with R12 which was a very good A/C refrigerant , R 134A is nowhere as good & that's why we find it helps enormously by installing Parallel flow condenser/s 

Regards

Bruce Buchanan 

[bteoh]

Hi Bruce,

Thanks for the very detailed explanation of the aircon in the earlier 944s , like the one I have.

I shall try to look at the mounting brackets for the compressor to see if it has the factory air con?

At least I know now why it can’t pull about 4 Degrees at the vents.

Cheers,

Brian

[Ross B]

23 hours ago, Buchanan Automotive said:

I nearly fell of my chair laughing , the poor guy was talking about some other car

His comments were not spcifically directed at Porsche aircons,  he was referring to early aircons in general using heater fans that didn't have the grunt to move sufficient cold air around the car interior. 

Ross 

[Buchanan Automotive]

Hi Ross , I had to read it a 2nd time , may be the terminology is not quite correct , I took as meaning the A/C air flow and air speed / volume of air to the center vent was being moved or pushed along by the heater fan & in you're 1985 ( if it has factory A/C ) is not the case at all as the A/C air flow is carried out by the evaporator fan motor instead

Interestingly , as we know the factory A/C 944 some rare 1982 models & most 1985 models had two interior fans , one that is the 1970's 924 interior demist & heater fan motor & if the car has factory A/C the 2nd & slightly more powerful evaporator fan motor ( remote mounted unit ) , this 2nd fan  blows  the A/C air to the center vent & is not that well designed & hence the shortcomings 

Once the money was available Porsche started to do what the Japanese manufactures were doing & that's incorporating everything into a properly designed climate control / heater / A/C system in one assembly  ( integrated ) this allows the use of ( in the case of the 944 1986> ) a very large single fan motor with the shaft out both ends with large fan wheels on either end , making an immensely powerful multi function fan motor , and powerful evaporator motor all as one, sending the cold A/C air from the colder & much larger evaporator ( in the dash & not down on the floor ) to each 4 large dash air vents  = problem solved

Regards

Bruce Buchanan

 

[Jason E]

For what it's worth in late 2016 Buchanan's did a comprehensive overhaul of my S2 upon purchase.  One of the things that was given attention was the A/C so that I wouldn't melt here in Brisbane summers.  Bruce installed a new parallel flow condenser & the A/C now works extremely well.  Even on a few of the 38 deg days just passed the cabins was cooled to perfection within minutes.  I couldn't be happier - money well spent.