Please advise on A/C conversion

Fri Jul 19 08:45:10 EDT 2002

Yeah, the clutch even sounds bad. It screeches for a second or two every time the compressor kicks in, no it's not the belt. So, I'd bet your right about the clutch being on it's way south. Any clue how expensive a new compressor clutch is? Can it be replaced without dis-charging my system? Got a part number by chance? Or am I better off just replacing the compressor & clutch at the same time?

Dave

Too Many Toys:
2002 VW Jetta GLS 1.8T Tiptronic
1993 RX-7 R1
1987.5 Audi Coupe GT "Special Build" 2.3 - Anthracite Black
1985 Chevy Impala Interceptor

-----Original Message-----
From: Roa, Greg [mailto:Greg.Roa at Cinergy.COM]
Sent: Friday, July 19, 2002 7:25 AM
To: David Ullrich - 0018 HQ
Subject: RE: Please advise on A/C conversion

Well, if it isn't engaging very well, but the valves and rings in the compressor are good, then I would guess that it could eventually get to the right pressure, but take a long time to do so...  I guess my question would be, do the pressures get to the right point within a few seconds, or does it take several minutes for them to drop...
I checked yesterday.  I started up my car, and just let it idle.  Had 125 degree vent temps, turned on the A/C with the windows still closed, and left the car idle.  Had vents down to 70 degrees in about a minute and a half, and to 60 degrees within 3 minutes.
Greg Roa

-----Original Message-----
From: David.Ullrich at ferguson.com [mailto:David.Ullrich at ferguson.com]
Sent: Thursday, July 18, 2002 3:54 PM
To: Roa, Greg
Cc: quattro at audifans.com
Subject: RE: Please advise on A/C conversion

Yup about the same weather here, 95* with very high humidity(heat indexes of 100-105 today). If the clutch is bad, would the pressures be right and the vent temps eventually come down properly?

Dave

-----Original Message-----
From: Roa, Greg [mailto:Greg.Roa at Cinergy.COM]
Sent: Thursday, July 18, 2002 3:40 PM
To: David Ullrich - 0018 HQ
Subject: RE: Please advise on A/C conversion

I doubt the overfill would have caused the problem.  I've got my system a little overfull too.  I've got almost the full amount in the system that is recommended for R-12.  Whoops.
That's odd that it will only drop to 70 after that long.  I'm missing two of the cardboard things on mine too.  Doesn't seem to make that big of a difference.
I'm in Cincinnati, OH.  Probably have similar weather to you.  Today is an about average day, for summer, it's 90 outside, and very humid.
I wonder if the clutch on your compressor isn't working right.  Just seems odd that it would take that long.  I dunno.

Greg Roa

-----Original Message-----
From: David.Ullrich at ferguson.com [mailto:David.Ullrich at ferguson.com]
Sent: Thursday, July 18, 2002 3:10 PM
To: Roa, Greg
Subject: RE: Please advise on A/C conversion

On my typical commute home, it is stop & go traffic up to about 45 mph for the first 5 minutes or so then highway speeds of around 65-75 for the next half hour or so. It will usually only drop from 140 to around 70 by the time I hit the highway. I have no bottom cardboard air duct, a poor engine side one, a perfect fender side one and a good top one. I'm using a pretty decent pusher fan that comes on whenever the compressor kicks in. This is very strange. I wonder why there is such a difference between out cars? Could a slight overfill cause this? Or maybe outside weather differences? Where are you located? I'm in SE Virginia.

I ordered a can of QuickBoost earlier today. From the research I did and from a friend who is a chemical engineer and looked over the technical specs, it actually should make up to a 10% or so difference, which would put my lowest temp back down to around 42-43* (back where it was with R12). If this stuff works as advertised, I'll surely let the list know...

Dave

-----Original Message-----
From: Roa, Greg [mailto:Greg.Roa at Cinergy.COM]
Sent: Thursday, July 18, 2002 2:59 PM
To: David Ullrich - 0018 HQ
Subject: RE: Please advise on A/C conversion

One other question, what is your typical drive like?  The system cools off much much quicker in scenarios where the compressor is not running at idle speed for a long period of time.   Example, if I start out from work, and drive at 55 mph for 3 minutes, I will be down to 55 degrees.  If I run the car at idle, it may take 6-7 minutes to drop to 55.  60 degrees is still only a few minutes after I turn it on, but it is a bit slower.
The difference between charcoal and black is minimal, so that shouldn't make much of a difference.  My paint is a few shades away from black, like a very very dark grey.  If you casually looked at it, it would look black.
I attached a pic of the color.  Kind of dirty there, and with the old wheels, but you get the idea.

-----Original Message-----
From: David.Ullrich at ferguson.com [mailto:David.Ullrich at ferguson.com]
Sent: Thursday, July 18, 2002 2:51 PM
To: Roa, Greg; quattro at audifans.com
Subject: RE: Please advise on A/C conversion

OK, maybe my compressor is dying. The low side is a bit high, but the high side is about right (possibly a tad high). I too have vent temps of around 140 at startup, but it DOES take 10 minutes or so to get below 60*. Still bottoms out in the same range (47-50* on any day). Can anybody shed some light on this? Would a slight overfill cause it to take longer to cool down yet still reach the same terminal temp? Would the fact that I have a black exterior and he has a charcoal account for this difference? Or is it just acceptable variation from car to car? Why is it taking longer in my car, yet the terminal temperatures are the same?

Dave

Too Many Toys:
2002 VW Jetta GLS 1.8T Tiptronic
1993 RX-7 R1
1987.5 Audi Coupe GT "Special Build" 2.3 - Anthracite Black
1985 Chevy Impala Interceptor

-----Original Message-----
From: Roa, Greg [mailto:Greg.Roa at Cinergy.COM]
Sent: Thursday, July 18, 2002 2:44 PM
To: David Ullrich - 0018 HQ; quattro at audifans.com
Subject: RE: Please advise on A/C conversion

My 4kq is charcoal (more or less black), with grey interior, and no tint either.  Usually when I start the car at the end of my work day, I have a vent temperature of about 140 degrees.
Even with this, I have no problem getting the temperatures down very quickly, usually in less than 5 minutes, I have vent temps around 55 degrees.

My one curiosity, and a question for the list, is what regulates the compressor duty cycle?  Even with the very low high side pressures I see, my compressor still cycles on and off normally, as if it is on a timer.  What gives the compressor it's signal?

Greg Roa
Cincinnati, OH
86' 4kcsq
93' 90 CS
83' 944

-----Original Message-----
From: David.Ullrich at ferguson.com [mailto:David.Ullrich at ferguson.com]
Sent: Thursday, July 18, 2002 2:31 PM
To: Roa, Greg; quattro at audifans.com
Subject: RE: Please advise on A/C conversion

Yeah, my pressure seems OK. The high side is GREAT, but the low side actually a little too high IMHO (around 70 IIRC, but not sure). I think in my case, the time it takes is greatly dependent on the color of your car. My CGT is black with a black interior and no window tint. In the morning when the sun it not strong and temps are in the upper 70s, it will drop to 50ish within 4-5 minutes. It bottoms out in the 47-50* range you mentioned. But with R12 in it it was going down to around 40-42* before the high pressure flex hose blew. So, I think my compressor is OK, although loud (it squeals for just a second when it kicks in or turns off, not the belt). According to the TSB from Audi, York type compressors are not recommended for R134a conversion...who knows why.

Dave

Too Many Toys:
2002 VW Jetta GLS 1.8T Tiptronic
1993 RX-7 R1
1987.5 Audi Coupe GT "Special Build" 2.3 - Anthracite Black
1985 Chevy Impala Interceptor