Karl, I totally admit, I likely (almost surly) go overboard. But if a little is good, even less is better? :confused:

I started using nitrogen when working on my El Camino AC. I replaced the compressor, and kept having wonky pressures, and I just figured it had to be ice. The El Camino uses a orifice tube system and pressures to cycle the compressor. A new orifice tube is just a few dollars, and I kept getting blockages there.

That is when I bought the dual stage vacuum pump, and the nitrogen rig, and my mantra of "No more moisture" became a chant.

I sure wish Porsche had hired GM to build the AC system in the G body cars. The AC in the El Camino is astonishing. 34 degree cold air in minutes when the car sat in the sun all day. My commute home was 12 minutes. Get into a car that was 140 degrees inside, and before arriving home, I HAD to turn the AC down as I was cold.

Karl,
Nitrogen is used to displace or purge "air" from the internals of pipes and fittings (residential and commercial hvac copper line sets, and things like steel or stainless steel header and exhaust systems) to prevent oxidation in the welds and pipes.

Nitrogen is used to leak test using a delta comparison of low and high side pressure readings.

And, importantly purging and sweeping with nitrogen prior to pulling a vacuum with a pump to "purge" condensable gases, "air", as well as existing refrigerant gas and moisture in a system that is trapped in refrigerant oil (the oil in the lines, condensers, evaporators; here a high flow rate of nitrogen helps to create turbulence on the surface of the oil as well as pools of oil).

However, most repair shops and DIY's do not have a bottle of nitrogen and regulators hanging around.

Flow or sweep rate is typically 3-5 SCFH (standard cubic feet per hour); it sounds like a whisper. A purge to displace refrigerant gas in oil will be higher, a few blasts, to create the turbulence.

Before you do your pre-vacuum nitrogen purges and sweeps, swab your compressor outlet port with a cotton q-tip and inspect it with a 5 magnification to see if you have those black particles.

Thanks to you, Charlie---and Glen---nitrogen is a new fascination. Have looked into local sources for gear & gas. Not that expensive. That said, storing more gear is a condo-living challenge at this point (for me.) Can always squeeze in more stuff... BUT... is it genuinely worth it? More tools was once not questioned in the least. Now is different.

Compressor is in hand (since I took the engine out for a rebuild. Rebuild has yet to wrap up.) In meantime, am going through much of my car including AC. No black particles ;) . One Black Death was sufficient to learn what not to do.
.

Moving the EDF to serve the front condenser is in progress. Design is done in Onshape. Gap in ducting is where EDF positions. Got 3D print prices just to proof these 2 parts in plastic from Xometry and some of the other big players. $600 to over $1,000.

http://forums.pelicanparts.com/uploa...1718321412.jpg

http://forums.pelicanparts.com/uploa...1718321412.jpg

Through Craftcloud... $63. in a "Standard Resin." The wait is a few days more. Will have to see what the quality is like. Can't imagine getting all the dimensions spot on and so a proof to check the fit. Figure to tweak the file and do the final in "High-Detail Resin." Cost is about the same. Again, quality has yet to be seen.
.

Karl,
Can you draft me up a new RH ACL and get a quote on Craft?
The local orthopedic's lead time is crazy, and the front office staff
is always out to lunch.

Charlie... for Kuehlemon, anything is possible! We'll have martinis and discuss dimensions & color. :)

I suspect installation will be the hard part. :eek:

I could use a meniscus while you're at it...

$63 3D print job sourced through Craftcloud and done by SchmidtProto... Quality that arrived is impressive. Considering I was quoted $600 to $1,000+ by the big 3D print companies... who got the bear?

There are clearances of fractions of a mm in the CAD file and those dimensions printed right on. One area sagged very slightly resulting in a minor gap between the EDF and duct... No concern. Surface... very smooth. Where print supports were, there's minor dimpling. Have to look carefully to see these dimples. Finish on this particular 3D material scuffs easily.

Plan was for this first printing to not fit. At least one round of refinements and a second printing was expected. No need. I f'd up one dimension but doesn't matter---Intake fits snuggly through hole in tub when 2mm clearance was allowed for all around. Spent a good deal of time messing with that area and finally decided to proof it and see what happens. There's an off angle relationship in the car between the intake and outlet that makes this an interesting area to measure. Look at the CAD drawings and you can see this off angle.

http://forums.pelicanparts.com/uploa...1719925493.jpg

http://forums.pelicanparts.com/uploa...1719925493.jpg

http://forums.pelicanparts.com/uploa...1719925493.jpg

Smooth.

Before installing, will test run the EDF to see if there is anything odd happening... like a whistle! Never know with this custom build stuff.
.

It will be interesting to see how it fits and works. You are a master tinkerer and I am amazed.

http://forums.pelicanparts.com/uploa...1719933641.jpg
This is the bottom of my water bottle holder. My 911 came with cassette storage in the center console. I need cassette storage like a new a buggy whip.

http://forums.pelicanparts.com/uploa...1719933641.jpg
I filled the voids with expanding foam, and then I painted it the Burgundy stock color for plastic paint at the local auto paint store. It is pretty close to my interior color.
http://forums.pelicanparts.com/uploa...1719933641.jpg

The final result is just what I wanted. It keeps the water bottle cool for quite a while, and looks OK. My business partner designed it and printed it for me. He has a better printer now so I may have him reprint it and then sand down the top of it to look better before I paint it. This was my prototype and I have been too lazy to do it over. In the car, it looks fine. It is wonderful for road trips.

http://forums.pelicanparts.com/support/smileys/wat6.gif

Glen... there's a thread about what's to do with center console cubby. Was going to suggest you put your cooler in there---but then you probably already have! I thought you were in Boca.

This thread is amazing and its great to see someone finally using this fender cavity on the 911. I'll remember this for when it's time to rebuild the AC.

Yea, I was in Boca, but we were so busy every day I did not have time to stop by and see ya. In 2025 Porsche Parade is in Oklahoma City. I will have a 12 mile drive. You should attend, it will be an epic week!

http://forums.pelicanparts.com/support/smileys/wat6.gif


Now I recall Glen, you were visiting back then. US tour has been in my head for a while but doesn't get past that. Perhaps in '25 it will happen. Let you know.


This AC project is running alongside a fuel consumption issue with fuel taking priority. So am dragging azz on AC. 3-wire power cable that was running from control gear under the dash through the tunnel, into the engine bay then into the fender well... have rerun that cable from the dash into the frunk for EDF's new location.

http://forums.pelicanparts.com/uploa...1722093197.JPG

Front condenser's stock barrel fan's intake passage. Air comes in from behind valance & bumper ('80.) Small debris can / does get sucked in and deposited on top of the condenser. Only 4 screws to get the barrel fan off to have a look at plenum above condenser.


http://forums.pelicanparts.com/uploa...1722093197.JPG

EDF in rear fender well was only heard in cabin provided one knew what to listen for. Noise now is very noticeable. Intolerable. Needs a sound deadening wrap.