993 A/C Evaporator Upgrade
03-31-2008, 09:15 PM
#17
Racer
Thread Starter
Today I dropped by an auto A/C repair place and as soon as they hooked up the gauges, I was told there is a blockage somewhere in the system. The tech guesses in might be a bad dryer or problem with the expansion valve. I took my 993 back to Zotz for further evaluation. I will have to say it was cooling about the same with the new parts. The blockage might just have been there from the start. Will post more as the problem is isolated.
03-31-2008, 10:23 PM
#19
Racer
Thread Starter
The A/C tech commented that the pressures (Hi and Lo) were not equalizing, whatever that means. Something caught his eye after hooking up the gauges, prior to starting the car. Hope this helps...
03-31-2008, 11:44 PM
#20
Three Wheelin'
Be careful with AC techs not familiar with 993 system. The air pressures are too different. The low side pressure is lower on these cars than most. I dont think Griffiths makes claims that the use of their evap will lead to X degree reduction in cooling temps. I do know it is constructed better than OEM but as far as being more efficient??? The OEM one has lots of cooling vanes and fills in the space, not sure what else can be done unless your ready to replace the compressor etc.
Saying that you need a new drier is BS in my opinion - that is standard replacement that your original shop should have replaced. Same goes for expansion valve. It is true that you may have gotten a faulty bits but unlikely. I highly doubt your original shop would have kept the original items after spending all that labor ripping everything apart.
I konw that the cooling effectiveness of the 993 AC system is highly dependent on motor PRMs. High humidity and pulling in fresh air does not help either. Make sure you are recirculating air and that your baffles that control the air flow are correct. How to tell? If you have the windows buttoned up, and you smell someone smoking in car in front of you at an intersection, your pulling in hot outside air.
After repairing my cars AC I can say that the 993 has never "frozen me out". Look at the porsche specs for temperature (on the DIY site) and you will find that Porsche cooling numbers are not the most impressive. With that said, Ive driven across the Mojave desert when it was ~100F and the AC was cold - but I was running 3-4k RPMs - windows were up. If I were to open the windows, all benefits would be gone and it would take a few miles to get cold again. The car has lots of thermal loading (look at all that glass in the rear).
Bottom line - your AC should be cold - not cool - but cold. However if you are looking at GM or Ford V8 cooling performance, I dont think you are going to get it! I can say that Ive been "frozen out" of my Ford F150, it will never happen in the 993.
I may be wrong - if you think I am, please post your cooling temps and ambient conditions (RPMs, outside temps etc...
Saying that you need a new drier is BS in my opinion - that is standard replacement that your original shop should have replaced. Same goes for expansion valve. It is true that you may have gotten a faulty bits but unlikely. I highly doubt your original shop would have kept the original items after spending all that labor ripping everything apart.
I konw that the cooling effectiveness of the 993 AC system is highly dependent on motor PRMs. High humidity and pulling in fresh air does not help either. Make sure you are recirculating air and that your baffles that control the air flow are correct. How to tell? If you have the windows buttoned up, and you smell someone smoking in car in front of you at an intersection, your pulling in hot outside air.
After repairing my cars AC I can say that the 993 has never "frozen me out". Look at the porsche specs for temperature (on the DIY site) and you will find that Porsche cooling numbers are not the most impressive. With that said, Ive driven across the Mojave desert when it was ~100F and the AC was cold - but I was running 3-4k RPMs - windows were up. If I were to open the windows, all benefits would be gone and it would take a few miles to get cold again. The car has lots of thermal loading (look at all that glass in the rear).
Bottom line - your AC should be cold - not cool - but cold. However if you are looking at GM or Ford V8 cooling performance, I dont think you are going to get it! I can say that Ive been "frozen out" of my Ford F150, it will never happen in the 993.
I may be wrong - if you think I am, please post your cooling temps and ambient conditions (RPMs, outside temps etc...
04-01-2008, 01:02 AM
#21
Race Car
You don't say where you are in Central Fl, but Eibell Performance in St. Petersburg did a great job making my car cold. No affiliation, etc...Or there's always ViperBob's shop here in Tampa; http://vortexmotorsport.com/index.shtml
I gotta believe that he'd know a little about it.
I gotta believe that he'd know a little about it.
04-01-2008, 11:12 AM
#22
Three Wheelin'
I checked out Griffiths page and I was wrong, it looks like they make a general claim that their evap performs better than OEM. Nothing specific about the 993. Id give them a call once you know *exactly* what was replaced and what your temps are coming out of the vents.
04-01-2008, 07:12 PM
#23
Racer
Thread Starter
Hey, I would be happy with comfortable in 90+ degree weather. Yesterday I returned my 993 to Zotz's and am sure they will find the problem or whatever can be done to improve the cooling. Last night Griff (of Griffiths) replied to my questions. See below. He really seems to know his stuff with A/C. For now, I am in good hands with the guys at Zotz Garage. Will post their findings.
My questions are in bold and Griff's answers are not.
Today I stopped by an auto air conditioning shop and a mechanic put the gauges on with the motor off. He found the pressure off and after starting the car remarked the pressure was not equalizing. When you attached gauges to a car and the system is not on, the low and high side gauges typcially
are equalized. When you start the ac system normally you will have a low side gauge reading between 20-40 psi and high side gauge reading
between 180-300: the ranges depending of both low and high side will depend upon the following:
A) the ambient outside air temperature
B) the amount of refrigerant in the system
C) the state of the expansion valve, open or closed
D) whether the clutch is engaged at a particular moment
E) whether the condenser fan is running
F) other variables that show up which relate to system problems
He further stated he believe there was a blockage in the system. The a/c mechanic guess it could be a blocked dryer or problem with the expansion valve. Before addressing this further I'm still pondering his "remark the pressure was not equalizing". The only time you will have equalized pressures is:
A) after the system is off or awhile or before the system starts, or
B) if your compressor is malfunctioning: the piston bores are scored or the reed valves are not closing properly.
I sense that based on your comments, if the technician is experienced in general automotive ac that maybe you misunderstood his comments.
You might ask him to clarify it for you better or ask him to clearly write it on a work order for you.
I later dropped by the original Porsche mechanics place and let them take a look. They also remarked the pressure was not right and will now go over their work and also check out the condensor.
Based on what I'm reading here it sounds like one mechanic did the work and another shop checked it? However you are also saying that a mechanic
stated pressures were not right they want to check their work (a good idea). Whether the pressures are not right when the system is "off" (not running) or "on" (compressor pumping) simply means the mechanic noted what he thinks is abnormal and he has to trouble shoot the system to figure it out.
Have you had any returns on dryers with problems or by chance does this sound familiar at all? Thanks.
Never. Whether it was a drier for a 944, 928, 964 or 993, we have never had a warranty claim, suspect or otherwise on a "new" drier.
Driers seldom fail out of the box. Problems dealing with moisture in the system are usually related to not evacuating and purging the system
properly. Although one funciton of the drier is absorb moisture, there is a limitation as to how much moisture they can hold.
Any residual moisture in a 'new' drier evaporates when you properly evacuate the sytsem.
I think at this point you have to stick with one competent technician, preferably the one who installed the components, evacuated, charged and tested
the car. They are not suppose to release the vehicle to you unless it is peforming to spec. right?
.....when I picked the car up, it was not that much cooler. Perhaps 5 degrees colder
The only way to know whether a system is peforming properly is to document observations accurately using tools of the trade.
In the world of auto ac the technician will document the following and it should appear on the work order, if it does not simply ask them to put it in writing and give you a copy:
A) Amount and type of refrigerant used
B) Amount and type of refrigerant oil used
C) The ambient temperature (outside) when the vehicle pressures and vent temperatures were noted, as well as test drive performance.
D) The low and high side pressure at idle
(this is all 'basics').
While you are at it also ask the technician to confirm if all the climate control doors (vents for fresh air, heat and ac) are operating correctly;
open when they should be and closed when they should be; there are few problems with 964 and 993 vent actuators.
My questions are in bold and Griff's answers are not.
Today I stopped by an auto air conditioning shop and a mechanic put the gauges on with the motor off. He found the pressure off and after starting the car remarked the pressure was not equalizing. When you attached gauges to a car and the system is not on, the low and high side gauges typcially
are equalized. When you start the ac system normally you will have a low side gauge reading between 20-40 psi and high side gauge reading
between 180-300: the ranges depending of both low and high side will depend upon the following:
A) the ambient outside air temperature
B) the amount of refrigerant in the system
C) the state of the expansion valve, open or closed
D) whether the clutch is engaged at a particular moment
E) whether the condenser fan is running
F) other variables that show up which relate to system problems
He further stated he believe there was a blockage in the system. The a/c mechanic guess it could be a blocked dryer or problem with the expansion valve. Before addressing this further I'm still pondering his "remark the pressure was not equalizing". The only time you will have equalized pressures is:
A) after the system is off or awhile or before the system starts, or
B) if your compressor is malfunctioning: the piston bores are scored or the reed valves are not closing properly.
I sense that based on your comments, if the technician is experienced in general automotive ac that maybe you misunderstood his comments.
You might ask him to clarify it for you better or ask him to clearly write it on a work order for you.
I later dropped by the original Porsche mechanics place and let them take a look. They also remarked the pressure was not right and will now go over their work and also check out the condensor.
Based on what I'm reading here it sounds like one mechanic did the work and another shop checked it? However you are also saying that a mechanic
stated pressures were not right they want to check their work (a good idea). Whether the pressures are not right when the system is "off" (not running) or "on" (compressor pumping) simply means the mechanic noted what he thinks is abnormal and he has to trouble shoot the system to figure it out.
Have you had any returns on dryers with problems or by chance does this sound familiar at all? Thanks.
Never. Whether it was a drier for a 944, 928, 964 or 993, we have never had a warranty claim, suspect or otherwise on a "new" drier.
Driers seldom fail out of the box. Problems dealing with moisture in the system are usually related to not evacuating and purging the system
properly. Although one funciton of the drier is absorb moisture, there is a limitation as to how much moisture they can hold.
Any residual moisture in a 'new' drier evaporates when you properly evacuate the sytsem.
I think at this point you have to stick with one competent technician, preferably the one who installed the components, evacuated, charged and tested
the car. They are not suppose to release the vehicle to you unless it is peforming to spec. right?
.....when I picked the car up, it was not that much cooler. Perhaps 5 degrees colder
The only way to know whether a system is peforming properly is to document observations accurately using tools of the trade.
In the world of auto ac the technician will document the following and it should appear on the work order, if it does not simply ask them to put it in writing and give you a copy:
A) Amount and type of refrigerant used
B) Amount and type of refrigerant oil used
C) The ambient temperature (outside) when the vehicle pressures and vent temperatures were noted, as well as test drive performance.
D) The low and high side pressure at idle
(this is all 'basics').
While you are at it also ask the technician to confirm if all the climate control doors (vents for fresh air, heat and ac) are operating correctly;
open when they should be and closed when they should be; there are few problems with 964 and 993 vent actuators.
04-02-2008, 08:52 PM
#24
Racer
Thread Starter
I picked up my Silver Racer from Zotz Garage today and I believe they have tweeked it for the better. The guys checked out their original work, cleaned the condensor and replaced a ceramic resistor that was broken (in half) that controls the condensor fan at low speeds. I am now pleased with the cooling and believe it was well worth the expense and trouble. I would highly recommend Griffith's products and of course the local garage here in Winter Park, Zotz. There is nothing like guys who work in a garage that love Porsche cars as much as their customers!
04-02-2008, 08:59 PM
#25
Race Car
Good news! The resistor was one of the tweaks done to mine too. Apparently, that fails a lot. There's another one, possibly identical, that controls the oil cooler fan as well. Both of mine were bad.
Glad you have cold air now! It's like Summer's here outside now. I hear thunder as I type this...
Glad you have cold air now! It's like Summer's here outside now. I hear thunder as I type this...
04-02-2008, 10:10 PM
#26
Race Car
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I picked up my Silver Racer from Zotz Garage today and I believe they have tweeked it for the better. The guys checked out their original work, cleaned the condensor and replaced a ceramic resistor that was broken (in half) that controls the condensor fan at low speeds. I am now pleased with the cooling and believe it was well worth the expense and trouble. I would highly recommend Griffith's products and of course the local garage here in Winter Park, Zotz. There is nothing like guys who work in a garage that love Porsche cars as much as their customers!
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