4k/CGT/Urq owners! Get you A/C ICE cold!!! (long)

[Roa, Greg]

Mine was still getting down to 40 degrees with an ambient temp of 88 before I adjusted the screw the last time, so I think it's working pretty well.  I'll check to see how long it takes from 125ish degree vent temps this afternoon.  The other thing that I'd like to do is check my system pressures now that I changed this.  I figured that my compressor was worn, as I was never getting very high pressures on the high side, but I wonder if it was simply that it never ran long enough to build pressure.

As far as running longer duty cycles, I would simply worry that the compressor would overheat.  Mine can get hot if running for too long, so I wanted to make sure that it wasn't running constantly, and had a chance to cool down.  I suppose the advantage to having longer duty cycles is that the clutch isn't cycling on and off as often, so wear from that standpoint would decrease.

As far as having the evaporator freeze, I guess you could freeze between the fins, and block the flow of air, so you wouldn't get any cooling.
I don't know if this can cause other problems.

Good Luck!
Greg Roa
Cincinnati, OH
86' 4kcsq <<  Needs a front leather seat bottom.  Got one?
93' 90CS
83' 944



-----Original Message-----
From: David [mailto:duandcc_forums at cox.net]
Sent: Tuesday, June 24, 2003 10:57 AM
To: Roa, Greg; quattro at audifans.com
Subject: Re: RE: 4k/CGT/Urq owners! Get you A/C ICE cold!!! (long)


I too have noticed that my compressor seems to run a LOT (never timed it) but I've got my vent temps around 38*F but it still takes a while to get that low. On my 8 minute commute to work it gets down to about 40-45*F in the mornings, and 50-55*F in the afternoons when interior temps start off at 120*F(on R134a). Other than increased wear, what is the downside of having longer dutcy cycles? Also, what are the real consiquences if the evaporator freezes? Just curious, as I have not been able to get a probe into the evap to make sure it is not below freezing. I would assume with this design it is intirely possible for the vent temps to be 38*F and the evap to be at or below freezing...

Dave
1987 CGT Special Build 2.3
SE Virginia
>
> From: "Roa, Greg" <Greg.Roa at Cinergy.COM>
> Date: 2003/06/24 Tue AM 10:04:24 EDT
> To: <quattro at audifans.com>,
> 	<duandcc_forums at cox.net>
> Subject: RE: 4k/CGT/Urq owners! Get you A/C ICE cold!!! (long)
>
> Well, I have been watching this on the Audiworld forums since I saw David mention it here, and had been meaning to do this.  After he mentioned that it worked out well for him, I thought I'd give it a shot.
>
> I took my glovebox out last night, and gave the screw a half turn.  My temps had been around 51 or so, after a few minutes (134a converted, new dryer, exp valve, and a compressor I resealed).  With a half turn, my vent temps dropped to about 48.
> Went back and gave it another 3/4 turn.  Went for a drive then, and my vent temps were fluctuating between 38 and 41 degrees.  I was tempted to leave it there, but the compressor was running at nearly 100% duty cycle during lower speed driving, so I backed it out a bit.  I've now got temps hanging around 45 degrees, which makes the car nice and chilly.
>
> I had figured something wasn't right as my compressor would run for about 20 seconds, and stay off for 45 seconds or more, even when starting to cool down.  Now, it tends to run much longer after starting the A/C, making cooldown take much less time.
>
> More testing will follow this afternoon, as temps are supposed to be around 93F, and humid here.  To note, I was driving around 40mph, through varying terrain after adjusting the car, and cooldown was very quick.  Didn't measure how long it took to attain max cooling, but I'll do that today, using highway driving on the trip home from work.
>
> I'm kind of suprised that the bentley makes no mention of this adjustment screw in the sections devoted to A/C.   Good tip, and well worth the time it takes to do.
>
> Good Luck!
> Greg Roa
> Cincinnati, OH
> 86' 4kcsq  <<  Needs a front leather seat bottom.  Got one?
> 93' 90 CS
> 83' 944
>
>