4000 A/C R134a conversion - almost done

[Ti Kan]

Hi all,

Just wanted to report on my progress with the R134a A/C conversion
project for my 4000 4-cyl.  I did a lot of research and homework on this
project and it is finally coming to fruition.

It is now working!  Nice cold air.  I didn't do any measurements yet
but the vent outputs feels as cold, if not colder than the old system
ever did.

This is what I had done:
- Evacuated the old R12 refrigerant and mineral oil (put system under vacuum
  for an hour).
- Ditched the stock Mini-York compressor (what a boat anchor).
- Installed a new Sanden SD-5 (model 4509) R134a compressor, using a nice
  cast aluminum adapter bracket from ICE ( http://www.iceac.com ).  The
  bracket comes with all necessary hardware.  I only had to make a very
  minor mod to the bracket (drilled a couple bolt holes).  The new compressor
  comes pre-filled with R134a-compatible PAG oil.  I also got a pair of
  compressor fittings with built-in R134a specification service ports from
  ICE.  No adapters needed.
- Changed to a slightly longer V-belt due to the adapter bracket and
  compressor geometry (was 13x825, new belt is 13x850 ribbed belt made by
  Continental).
- Replaced the receiver/drier with a new R134a-compatible unit.
- Replaced the expansion valve.
- Had a local A/C shop build new suction and discharge compressor hoses
  using the appropriate R134a barrier hoses, install all new green nitrile
  o-rings, and changed system with R134a.

What's left to do:

- Upgrade the radiator fan to the 1984-87 4000 dual-fan setup to increase
  air flow through the condensor.  This should yield better A/C performance
  at idle or low speed conditions.
- Install an A/C idle air bypass valve (This valve opens when the compressor
  clutch is engaged, and provides a small idle speed compensation.  Stock on
  many later model Audis, but my early 4000 doesn't have one).

The new Sanden compressor uses noticeably less engine power than the old
Mini-York, not to mention that it's nice and quiet compared to the clackety
clack of the York.  The installation is very professional and stock-looking.

This conversion wasn't cheap, but it is done right and should provide
superior performance over the long haul.  I am a happy camper.

-Ti
01 S4 2.7 biturbo quattro
84 5000S 2.1 turbo
80 4000 2.0
-- 
    ///  Ti Kan                Vorsprung durch Technik
   ///   AMB Research Laboratories, Sunnyvale, CA. USA
  ///    ti at amb.org
 //////  http://www.amb.org/ti/
///