Peter M Posted 22December, 2013 Report Share Posted 22December, 2013 Time for a real world comparison as frankly there is a lot of BS on the forums about air conditioning performance.Took my 6 month old Subaru Outback for a steady drive that was long enough for temperatures to stabilise. With an ambient temperature of 35 degrees on a cloudy day, the minimum vent temperature I could a achieve was a rock steady 5 degrees. This shouldn't be a surprise as it obviously has a variable displacement compressor (ie it runs all the time, just the piston stroke varies to run the evaporator as close to zero as possible without causing icing)Interestingly, setting the climate control to my normal 22.5 degrees gave a vent temperature that varied between 8 and 10 degrees.Transferred my probe thermometer to the 911 and driving the same route all in the space of 30 minutes and guess what!Vent temperature cycled between 5 and 9 degrees.I was pretty pleased with that! Link to comment Share on other sites More sharing options...
OZ930 Posted 23December, 2013 Report Share Posted 23December, 2013 Good work ! Link to comment Share on other sites More sharing options...
cyberpunky Posted 23December, 2013 Report Share Posted 23December, 2013 excuse the pun but that is very cool Link to comment Share on other sites More sharing options...
Russ Posted 23December, 2013 Author Report Share Posted 23December, 2013 sounding good, how does it go cooling down the car? or is it more just blowing cold air on you? Link to comment Share on other sites More sharing options...
Peter M Posted 23December, 2013 Report Share Posted 23December, 2013 Russ, Yes, it definitely does cool the car down and makes it a pleasant place to be but to replicate a modern car that creates a cloud of cold air around you instead of noticeable zones of different temperatures will require more vent area. Kuehl make under dash supplementary vents which would do the trick at a price. However their additional centre vent would have to be plumbed differently due to the difference in the RHD and LHD factory fit so it would work out a very expensive approach in the end. I notice Vintage Air and many others sell the same under dash vents as Kuehl do at literally a fraction of the price but would require you to source your own hose and the Y pieces. I'm leaning this way at the moment to do the side vents at the very least. All bolt on without any hacking as I'm not doing anything that can't be reversed. Did you get a price from for a rear mud guard mounted condenser? I'm just curious! Link to comment Share on other sites More sharing options...
Russ Posted 24December, 2013 Author Report Share Posted 24December, 2013 I'm just waiting on a price back for the extra vents and rear guard mounted condenser - I'll post here when I know I have to renew some seals to stop air leaks as well in the meantime do you get a noticeable difference in performance when running air con? Link to comment Share on other sites More sharing options...
Guest hepkat63 Posted 24December, 2013 Report Share Posted 24December, 2013 Russ, Yes, it definitely does cool the car down and makes it a pleasant place to be but to replicate a modern car that creates a cloud of cold air around you instead of noticeable zones of different temperatures will require more vent area. Kuehl make under dash supplementary vents which would do the trick at a price. However their additional centre vent would have to be plumbed differently due to the difference in the RHD and LHD factory fit so it would work out a very expensive approach in the end. I notice Vintage Air and many others sell the same under dash vents as Kuehl do at literally a fraction of the price but would require you to source your own hose and the Y pieces. I'm leaning this way at the moment to do the side vents at the very least. All bolt on without any hacking as I'm not doing anything that can't be reversed. Did you get a price from for a rear mud guard mounted condenser? I'm just curious! Good on you Peter for doing this ! When I was looking around at purchasing my Porsche - Air Conditioning was high on the tick box list - been living too long in a rural area and driving modern cars to go without it ! I too looked at the retro fit option (in case the car i found did not have AC fitted) and saw nothing but positive comments on the US forums. Link to comment Share on other sites More sharing options...
Peter M Posted 24December, 2013 Report Share Posted 24December, 2013 Steve, you're not alone on this point and notice in the latest edition of Wheels magazine that Stahly is going through the same thing with his C3.2. (He's been doing regular updates on his ownership experiences in the last few months and is the first story I always read now.) He also manages to be a whole lot more amusing talking about it than I do though! Link to comment Share on other sites More sharing options...
Peter M Posted 24December, 2013 Report Share Posted 24December, 2013 ....do you get a noticeable difference in performance when running air con? Nah Russ, haven't noticed a difference except the revs drop quicker when changing gears! Link to comment Share on other sites More sharing options...
clutch-monkey Posted 24December, 2013 Report Share Posted 24December, 2013 yeah you have to be careful if you have a lightweight flywheel etc - aircon used to make my car stall haha Link to comment Share on other sites More sharing options...
Peter M Posted 24October, 2014 Report Share Posted 24October, 2014 The aircon guy has just left, coming back Monday to pull out out compressor, send to Melbourne and rebuild the guts.He says the nippondenso unit in the 944 is totally rebuildable and a very good unit so there should not be any reason that it won't be cold with a new drier as well, apparently this is the thing that helps the air con really work. He says the units in the older 911's were not so good but still effective enough to keep you cool.Sitting at the lights and in traffic no auto air is that good you still need the ram air to keep the system cool.He cleared something up as well about the old porous hoses that were used with the older "nasty" gas. The compressor has some oil in it and the older mineral oil that was used coats the inside of the hoses and makes a type of lining, so their is really no need to replace these old hoses unless they are leaking. He also tells me that even 60 seconds of running the A/C a day is enough to lube everything and keep it all good. Topped up the outback with gas as well while he was here, it was about 20% down, it went from about 9 deg down to about 5.5 deg and while it doesn't sound like much, I can really feel the difference in cooling.I've got to say I'm impressed with your AC man!Had him around regassing my 993 after changing the receiver/dryer and it's great to find someone who knows what he is doing. Home service and very keenly priced.Thanks for sharing!(For the Newcastle guys, call Mark Baber at CMS Auto Air http://www.cmsautoair.com/ ) Link to comment Share on other sites More sharing options...
carl888 Posted 4November, 2014 Report Share Posted 4November, 2014 It seems the 911 air conditioning system really polarises people. I have a 1987 Carrera that's had some work performed in the air conditioning department. When the car was new I recall the first charge of R12 only lasted about 3 years. (Contrast this with my brothers 1994 C180 that's never been gassed since delivery and measures 3 degrees at the vents, still). Around 1990 or so the 911 was converted to 134a and that's when the trouble began. The temperature never went below about 9 degrees at the vents and the charge would only last a season. I battled on with this for the next ten or so years then in about 2000 decided to look at it myself. As it turns out the Nippondenso compressor had a leaking seal so I sent that off to be re-built. From then on, a charge would last 3-4 years but really, since the 134a conversion, the system was still average at best. Coupled with this is the cars black partial leather interior, anything above about 25 degrees ambient was simply unpleasant, and actually was the main reason the car was never enjoyed much over the summer. I threw a tantrum with it a few years back and despite wanting to keep the car as original as possible, I changed all the lines and fitted a Sanden compressor, the seals in the original Nippondenso had failed again. I cannot say how the system performed with the Sanden compressor and the R134 as I filled it with Hychill. Immediately the air temperature at the vents went to 2 degrees. Joy of joys. My dad bought a 1978 911 SC new in 1978 and ordered it with air, the system used the older style York piston compressor and he recalls how well that worked back then. I think the combination of system integrity and a decent refrigerant is universal for any air conditioning system. Really, the 911 has no excuse for the system being inefficient, two condensors, one right up the front with no engine heat to speak of too. It should work. I'm a big advocate of Hychill. I've used it for years in some old Mercedes-Benzes from the 1970s and 1980s along with some 1970s Italian rubbish and its been revelatory. A pic of the 911 compressor. My apologies for the ribbed compressor belt. Link to comment Share on other sites More sharing options...
Coastr Posted 4November, 2014 Report Share Posted 4November, 2014 Time for a real world comparison as frankly there is a lot of BS on the forums about air conditioning performance. Took my 6 month old Subaru Outback for a steady drive that was long enough for temperatures to stabilise. With an ambient temperature of 35 degrees on a cloudy day, the minimum vent temperature I could a achieve was a rock steady 5 degrees. This shouldn't be a surprise as it obviously has a variable displacement compressor (ie it runs all the time, just the piston stroke varies to run the evaporator as close to zero as possible without causing icing) Interestingly, setting the climate control to my normal 22.5 degrees gave a vent temperature that varied between 8 and 10 degrees. Transferred my probe thermometer to the 911 and driving the same route all in the space of 30 minutes and guess what! Vent temperature cycled between 5 and 9 degrees. I was pretty pleased with that! I think like a lot of 911 things the AC is a bit more complicated than most other cars, so has more failure points. So the AC fails more often probably because of the separate condensers and lots of hose. And then those who have a car with inop AC continue to spread the word that it 'doesn't work anyway'. I have always found it hard to believe that Porsche would sell a car with useless AC. The contemporary road reports all complained about a difficult gearbox and weird ergonomics but none commented on a bad AC. So I think it's mostly from people not maintaining the systems and also converting to R134a. Link to comment Share on other sites More sharing options...
Dreamr Posted 4November, 2014 Report Share Posted 4November, 2014 So taking in all of the above comments , what do you guys suggest is the best way to get the "hopless" air conditioning to work in the notorius pre '85 911's?Does the compressor need to be replaced with a modern unit or Is this Hychill gas and a leak test the answer?Can the original system ever really work properly? Link to comment Share on other sites More sharing options...
carl888 Posted 4November, 2014 Report Share Posted 4November, 2014 The reality is the system wasn't hopeless when it was new. And yes, it can work properly, I've seen it first hand. I am not privy to the issues you're experiencing however I would have the system checked for leaks, specifically the hoses and compressor seals then have the system filled with Hychill and the appropriate oil. Just my opinion. Do bear in mind however that your air conditioning components are 30 years old, or older, and it may be time to replace parts. I cannot comment on the compressor, but I would be happy with the existing compressor provided I could get parts for it. Link to comment Share on other sites More sharing options...
Peter M Posted 4November, 2014 Report Share Posted 4November, 2014 Guys,I've got to disagree, the standard factory AC is limited by its operation being heavily reliant on vehicle speed to get adequate airflow over the condensors. The feeble front condensor fan and limited size of this condensor results in the AC being all but "hopeless" in stop start driving.This general feeblness was acknowledged at the time. See page 42: Also be aware these comments where made in reference to the super effective 12a refrigerant rather than the commonly demonised 134a.With AC in these cars, I think it is a "horses for courses" situation. If you want good AC in city driving you will need to first and foremost put an effective electric fan cooled condensor or two in the rear wheel well like what Griffith/Kuehl offer. I reckon you could make up a suitable setup from locally available parts for half their cost.If you only drive on the open road, the standard condensor configuration is OK I think.Also don't underestimate the limiting effect of the small AC dash vents in the pre '86 cars. The AC is only as good as the weakest link.As I said earlier half the battle in A/Cing old 911's is separating the BS from the facts.However I do agree with the comments to firstly check for hose leaks and correct, if the compressor works and the seals are OK leave it alone and importantly replace the receiver/dryer before you regas with your favored (environmental) poison.CheersPeter Link to comment Share on other sites More sharing options...
Peter M Posted 8June, 2015 Report Share Posted 8June, 2015 With AC in these cars, I think it is a "horses for courses" situation. If you want good AC in city driving you will need to first and foremost put an effective electric fan cooled condensor or two in the rear wheel well like what Griffith/Kuehl offer. I reckon you could make up a suitable setup from locally available parts for half their cost.As an alternative to the 1000 dollar Griffith/Kuehl wheel well condenser, this looks OK for half the price:http://www.allzim.com/store/cart.php?m=product_detail&p=1240 Link to comment Share on other sites More sharing options...
Coastr Posted 8June, 2015 Report Share Posted 8June, 2015 I drove mine on the weekend. I left it in the sun for a bit and it was a little warm. So I flipped the AC on the lowest setting to cool things out a bit. I only left it on for about 2 minutes before it got too cold. In summer it can barely keep up with the warmth and only manages to get things down to a bearable level. It's not working 100% though. So it really is all about the efficiency of the unit to remove warmth from the air and cabin. Link to comment Share on other sites More sharing options...
Peter M Posted 9June, 2015 Report Share Posted 9June, 2015 http://rennlist.com/forums/attachments/911-forum/928039d1429040106-87-coupe-ac-upgrade-wwested-ac-1-.jpgI find it interesting that no one I know offers commercially a electric fan retrofit kit for the engine lid mounted condenser but a number of places offer wheel well mounted additional condensers to improve AC performance at continuous slow speed or extreme temperatures.It is not as though the standard size front and rear condenser set up is small in area and would have to be nearly twice the size of the 964/993 setup. Further it is not as though the engine lid condenser suffers from heat soak from the engine as I'm always surprised how little heat radiates upwards from the engine.Surely for a hundred bucks or so spent on a couple of electric fans and a tri-switch that operates the fan when the AC line pressures reach a certain level would be a good, if not the best investment for improving performance. If you could mount the fans above the condenser rather than below so you can't see them would be even better.Hopefully someone with this sort of set up will chime in! Link to comment Share on other sites More sharing options...
Peter M Posted 20July, 2015 Report Share Posted 20July, 2015 Great inspiration for those preparing for summer:http://forums.pelicanparts.com/porsche-911-technical-forum/870573-another-boring-ac-thread-installing-993-condenser-3-2-carrera.html Link to comment Share on other sites More sharing options...
Coastr Posted 20July, 2015 Report Share Posted 20July, 2015 Are 964 condensers in the guard like that? Or is he just stealing the idea and using a stock part? Link to comment Share on other sites More sharing options...
Peter M Posted 20July, 2015 Report Share Posted 20July, 2015 The 964's and 993's have the evaporator condensor mounted in front of the LHS front wheel. I think he is just stealing an idea that's been promoted most widely by Griffith and just using a stock Porsche part. Link to comment Share on other sites More sharing options...
Coastr Posted 21July, 2015 Report Share Posted 21July, 2015 I think you mean condenser but thanks. I wonder why people are not replicating this position (the 964 spot) in the earlier cars? It would seem logical to me seeing as the evaporator is closer to the condenser in this setup. I assume Porsche did their sums correctly.Do 964s have an engine lid condenser as well? Link to comment Share on other sites More sharing options...
clutch-monkey Posted 21July, 2015 Report Share Posted 21July, 2015 I know some of us have oil coolers stuffed into each fender haha, no space for condensers Link to comment Share on other sites More sharing options...
Peter M Posted 21July, 2015 Report Share Posted 21July, 2015 I think you mean condenser but thanks. I wonder why people are not replicating this position (the 964 spot) in the earlier cars? It would seem logical to me seeing as the evaporator is closer to the condenser in this setup. I assume Porsche did their sums correctly.Do 964s have an engine lid condenser as well?Thanks Coastr for that correction! It's hard to post accurately when at work....I think owners of the pre 964 models rarely replicate the condenser placement of the 964's and 993's because there is little space at the front of the front wheel in the older cars even with the huge windscreen washer relocated. The 964's and 993's also have clever ducting in the front bumper that allows them better use of the space.The 964's and 993's only use one reasonably small condenser at the front and don't have an engine lid one at all. Link to comment Share on other sites More sharing options...
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