Type85 AC converions to R134a

Mon Aug 9 18:05:22 EDT 2004

I would point out that hydrocarbon refrigerants (enviro-safe, et al) are
compatable with mineral oil and old style seals. And they out perform R134a.
As an extra bonus they are non-toxic (unlike r134a). Some will be quick to
point out that they are flammable. True. But it you only charge about 12 oz.
(1/3 the r12 charge). Hardly a rolling bomb.
There are better non-flammable alternatives as well; R406a. R406a is also
compatable w/ mineral oil (which has advantages over ester) and out-performs
r-134 AND hydrocarbons. It does require barrier hoses though.
Just something to think about.
Also I would not adjust the low temerature (or pressure depending on the
vehicle) cutout to cycle at anything below 40F. This because you could have
locally colder temperatures on the evaporator wich can cause freeze-up. This
leads to no more cold air and sad passengers.
Steve

> -----Original Message-----
> From: quattro-bounces at audifans.com
> [mailto:quattro-bounces at audifans.com]On Behalf Of David
> Sent: Monday, August 09, 2004 4:47 PM
> To: Ed Kellock; quattro at audifans.com
> Subject: Type85 AC converions to R134a
>
>
> ============================================================
> From: Ed Kellock <ekellock at gmail.com>
> Date: 2004/08/09 Mon PM 02:09:59 EDT
> To: David <duandcc_forums at cox.net>
> Subject: Re: Somebody was looking for a CGT 2.3 auto?
>
> Dave, the a/c compressor on my 87 CGT 2.3 went south a couple years
> ago and I thought it might be a good time to convert to r143a.  Can
> you tell me what was involved in doing that on your car?
>
> Thanks,
> Ed
>
> ============================================================
> First you have to decide whether you can live with an AC
> system that will never cool quite as well as it did with R12.
> Audi does not recommend converting any car with the York Type
> compressor with good reason (some other compressors can be
> converted easier, but I have not BTDT with any of those). I
> had mine converted and it was a nightmare, but worked out in
> the end. On R12, from what I've heard, you should be getting
> vent temps at or below 40*F if the system is working
> properly. I've found that if you adjust the AC thermostat you
> can get even lower temps. My R134a converted system
> eventually gets down to the mid 30s. But it takes a LONG time
> to get there, 10+ minutes for so on a hot day when interior
> temps start high. An example would a while back when I left
> work. I hopped in the car and the vent thermometer (I just
> keep it in there) was showing 120 degrees. It took 10 minutes
> for so for the vent temps to drop to 50 on #3 blower setting
> (takes even longer on high). It hit 4
>  5 degrees within another 5 minutes or so. But when it's 95
> degrees out with high humidity, even 50 degree vent temps
> feel pretty good! So, do you think you could live with a
> slightly less efficient system?
>
> Now, onto the worst part, the conversion. First, if you are
> going to do this, do it right. That means replacing: service
> fittings, dryer, all o-rings/seals, and the expansion valve.
> Then flush everything (have to remove the compressor to flush
> it). Now evacuate for a minimum of 4 hours and make sure it
> will hold a vacuum, now refill with ESTER oil and fresh R134a
> (ester is R12 & 134a compatible and it is a good conditioner
> of seals and o-rings) and keep you fingers crossed.
>
> Now that everything is converted, I'd consider adjusting the
> AC Temp Sensor. This is the sensor that controls at whjat
> temp the compressor custs oput. The factory setting is around
> 42*F. I've adjsuted mine down to 34*F and am very happy.
>
> To adjust the temp:
> Remove the glove box as an assembly and lay it on the
> passenger floor. The Fuel Injection computer is attached to
> the right side of the glove box. Leave it there because
> you'll want to run the engine and drive the car around.
>
> With the glove box removed you'll be looking at the
> Evaporator. To the right of the evaporator is a small box,
> gold anadized in color, with a 14mm nut facing you to hold
> the box in place.
>
> This is the temp sensor for the evaporator core. Take note of
> the ether filled capilary tube that comes out the top of it
> and goes to the left across the front of the evaporator and
> then into the fins of the evaporator. Break this tube and
> you're screwed......so proceed with caution!!!!
>
> Undo the 14mm nut that holds the temp sensor switch in place.
> Lower the temp sensor and bring it and it's capilary tube
> outward just unit you can see and get to the top of it.
>
> On top you'll see a philips screw. This is the temp adjuster
> screw. Scribe a line on it and on the housing for reference.
>
> Turn the screw COUNTER-CLOCKWISE to lower the tempurature at
> which it turns off the compressor.
>
> As I said, mine was blowing 43 degrees. 2-1/2 turns
> COUNTER-CLOCKWISE got me to 30 degrees.
>
> So, make your adjustments slowly with the car sitting there
> running, doors and windows closed and see what you get. Take
> is slowly.
>
> Once you get where you want. Go for a test drive and see what
> you get on the road. I noticed I had to keep turning the
> screw counter clockwise a bit further to get 30 on a test
> drive.....as compared to what it took to get 30 in the driveway.
>
> With it torn down this far, it would be a good idea to remove
> and clean the evaporator drain pan.
>
> One thing to keep in mind, R134a molecules are much smaller
> than R12 and will find even the tiniest ways to leak out. So
> if your hoses are even marginal, those will have to be
> replaced too. Doing a R12 to R134a conversion properly is
> pretty expensive. My conversion including a new high pressure
> flex hose and all the things above was over $700. Others may
> tell you to just go to your FLAPS and buy the $35 conversion
> kit. Sure, it might work, but from what I've experienced, it
> won't work well or it won't work very long. One other thing,
> make sure your radiator fan is healthy (works on all speeds
> if multi-speed and pulls well). It would also help to put a
> pusher fan in front of the AC condenser to added air-flow over it.
>
> Overall, I guess I'm satisfied with the results. It works
> adequately and will make future recharges dirt cheap when
> compared to R12.
>
> Well, sorry for the novel, but HTH, YMMV. Good luck.
>
>
> Dave
>
> 1987 Coupe GT Special Build 2.3 (H4s, custom exhaust, Borbet
> Type Es with Kumho tires, Recaro Trophy seats, Euro 90 Sport
> 3 spoke steering wheel, 4Kq swaybar, Boge TurboGas
> struts/shocks Kenwood Bazooka & Blaupunkt stero system, R134a
> converted AC blowing 34*F, 35% metalic charcoal tint, fresh
> paint in original Anthracite Black)
>
> 2002 VW Jetta GLS 1.8T (wife's, stock)
>
> 1993 RX7 - R1 (shared toy, stock)
>
> 1985 Chevy Impala 9C1 (fun beater and boat tow vehicle, stock
> police package)
>
> 1978 Impala SW (stuff hauler, restored with crate new LT1 transplant)
>
> All in SE VA
>
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