Convert/retrofit to R134a or stay R12?

[Kenneth]

Tony or someone else will probably have a better answer, but from what I can tell each car application has slightly different plumbing, but the compressor itself is common across a few different makes and models.  The manifold provides the fittings/ports/connections in the correct orientation for the specific car, and replacement compressors are usually sold without the manifold so you reuse your existing one.

Tony has me thinking about trying to do a reseal of my existing compressor before looking for a new or rebuilt one.  I've read that often a compressor can be in otherwise good condition (hasn't seized or grenaded) and just has a leak at the seals.  Also, the conversion to a parallel flow condenser seems less daunting now that I see some of the universal ones offered for hot rods and custom installations online as well as on Ebay.  The biggest challenge is the hoses, because the mounting brackets look very flexible/adaptable on those universal units.

As far as elminating the manifold and going with a different and more universal compressor, I take that to mean going with a Sanden 508 type, which has a few options for the back plate with the ports that I suppose is different than a manifold in that it is actually part of the compressor housing and not bolted onto it.  Many of the universal type Sanden units have the fittings pointing radially away from the shaft axis, but there are others where the fittings point out the back axially if that fits better.  The Sanden "type" is suppose to be pretty efficient.  I'm not sure if it's better than our Type 44 Denso units, but it's considered an upgrade for the York ones in the Type 85s.

By the way, the best price I found on that Audi OEM conversion kit is $252.75 here:  

http://www.audiwholesaleparts.com/parts/1991/AUDI/200%20QUATTRO/20V/index.cfm?searchText=4a0298107a&siteid=215295&year=1991&make=AUDI&model=200+QUATTRO&submodel=20V&vehicleid=1007288

It has been said that everything in the kit can be purchased from most auto parts stores.

I guess I didn't realize it before, but the pressure relief valve is only specified to be changed on the conversion of the Zexel compressors, not the Denso units.  I believe that means that for the Denso-equipped cars the Audi OEM conversion kit is totally unnecessary compared to going with a more universal retrofit kit and replacement seals.  I imagine it's unecessary to go with the expensive Audi kit for the Zexel applications too if you can find the R134a pressure relief valve.

I'm getting into this a/c thing as I definitely want to be able to enjoy my 200q20v year-round.  I'm making a bit of a commitment to it or at least the 20vt big chassis (T44 and C4) platform because I've put on my suspension and RS2 parts, put 7A cams in it and now have joined in on the current group buy for a Stromung exhaust.  "Worst case," if something happens to take out both this car and my spare 200q20v, I can bring over the parts to a C4 and continue on the 20vt track.  By the way, I've been looking at water/meth injection and would like to get an Aquamist kit for the car.

Kenneth

---- Ed Kellock <ekellock at gmail.com> wrote: 
> What is the purpose of the manifold on the compressor?
> On Jun 20, 2013 7:09 PM, "Tony Hoffman" <auditony at gmail.com> wrote:
> 
> > Honestly, at that price point, I'd be looking to change the compressor and
> > lines to a different, more universal setup anyhow, and eliminate that
> > "manifold" alltogether. The biggest thing is the time it takes to do the
> > lines and find all the fittings you need. The rest is just bolt/weld up and
> > go.
> >
> > BTW, that o-ring seal manifold part that leaks on 90% of the ones I work
> > on, that is not replaced with the Compressor. That is a seperate part.
> >
> > Tony
> >
> > On Thu, Jun 20, 2013 at 9:18 AM, Kenneth Keith <auditude at cox.net> wrote:
> >
> > > So far what I’ve done is paid my $40 for “diagnosis” (“hey, your
> > > compressor is bad), and taken my car home.  I was/am planning on looking
> > > into a parallel flow condenser and new barrier hoses, and maybe an
> > upgraded
> > > evaporator from http://europeancoolerair.com/ftrmkt01.htm if it’s still
> > > available, and a new compressor.  This would let me get the most out of a
> > > R134a retrofit if I go that way now or in the future, but my thought on
> > it
> > > for now was that I will get some R12 off Craigslist for about ~$40/can
> > and
> > > go that way rather than the $80/can the shop would charge.
> > >
> > > If my compressor can be salvaged, then I suppose I’d want to go that
> > > route.  However, the “diagnosis” I paid for didn’t break down which part
> > of
> > > the compressor was leaking.  I think he just looked at it and saw dye
> > > around the outside and determined it was bad.  I haven’t gotten a chance
> > to
> > > look at it myself, nor to take measurements of the stock condenser to see
> > > what parallel flow versions are the closest fit.
> > >
> > > Are there any parts of this Audi retrofit kit that are useful or
> > necessary
> > > for a conversion on our cars?  Specifically, I’m wondering about the
> > > different pressure relief valve that’s included, which is not something I
> > > think is changed on the “$40 retrofits” where just the fitting adapters
> > are
> > > added.
> > >
> > > C system R-12 to R-134a retrofit guide
> > >
> > > I believe that kit, if I can find one, would include the manifold o-ring
> > > you mention is a potential leak source.  The kit seems to be around $333
> > or
> > > so if it can be found.
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