Another boring AC thread - installing a 993 condenser in a 3.2 Carrera
 

This is the year I'm finally fixing my AC.

Disclaimer: I know nothing about AC, despite having bookmarked and read 38 threads on this board. What I may do next may be dumb. I typically have to do things a couple times before I'm satisfied with the results.

I've decided to add a 993/964 condenser to my otherwise factory setup, and convert to 134a. I've purchased a Robinaire vacuum pump and a set of gauges, as well as a hose crimping tool.


outhttp://forums.pelicanparts.com/uploa...1434256682.jpg

Here are a few pics of the new condenser, purchased from our host for ~$100.

http://forums.pelicanparts.com/uploa...1434256840.jpg

The fan is from nostalgic AC. About $40, it's 10" diameter and reversible. Makes around 800 CFM. I tested the polarity w. A power supply and the flow was pretty huge.


http://forums.pelicanparts.com/uploa...1434257030.jpg

I messed around with a couple different bracket arrangements and settled on 1x1x1/8 aluminum angle on top 3/4" square al tubinghttp://forums.pelicanparts.com/uploa...1434257305.jpg

I glued cork gasket material down to Cushion the condenser. The hardware is SS. I cut the 45 angle off the end of the tubing in the final.

Here it mounted. I used 1" rubber stoppers from Ace hardware for the legs and 5/8x1/8 flat al bar for the top brace. This stuff was a lot less easy to bend than I expected, it wanted to break so I bent it very gradually, hence the curvy line.


http://forums.pelicanparts.com/uploa...1434257599.jpg

The flat bar in front will hold rock guard, to be finalized once I figure out the hose routing.

The fan will push for obvious reasons.

Feeling fairly satisfied on the condenser install, I decide to starting taking the original system apart

Look what I found on top of the deck lid condenser:

http://forums.pelicanparts.com/uploa...1434258142.jpg

This gob on the left was the consistency of dryer lint that had "set up" over the years. It didn't seem to be animal in origin (no bones or other hard chunks).

I cleaned it up, flushed it out and reinstalled it. Debated about leaving it out but decided to use it still. It's here, and it can't hurt right?

I removed my original denso condenser in order to drown the oil. Only got out a teaspoon or so

I was puzzled by this. It's still in the pan so maybe more will ooze out overnight. Yes I rotated it. Planning to add fresh ester oil on reinstall.

http://forums.pelicanparts.com/uploa...1434258585.jpg

When I removed the line from the deck lid condenser to the front condenser, it dribbled a good amount of oil on the floor, I'd guess 3-4 oz.

Tomorrow I'm going to build some hoses and try to get the front condenser out and flush it. I couldn't figure that out today despite removing the screws at both ends and removing the cover screen. (Any hints out there?)

Has anyone tried cutting the ferrules off the old hose fittings and re-crimping on barrier hose with new ferrules? I may cut one open tomorrow to see what it's like.

I remember reading a thread where someone reused fittings. Seems it should be possible if you're patient. Fitting sure don't wear out. I kept a box full when I upgraded my hoses, cut and disposed of the rubber.

Great job, Nathan. I think fittings are cheap, maybe $6-10. I would use new. You will need #6 and #8, and maybe a #6 that fits on a #8 hose.
Good luck,
Dave

Dave,

I actually bought a #6 to #8 fitting, yesterday I realized i don't really need it. The hose from deck lid is an 8, so I assumed the front condenser inlet was an 8, but it's really a 6! The outlet of the 993 condenser is a 6. For this reason I have a lot of #8 hose that should be 6. So, either use 2 #6 to #8 and have an oversized long hose, or I get more #6 hose.

Cheers
Nathan

Do people typically remove the washer tank to route hoses to the front condenser?

You don't want to put on a new ferrule exactly where the old one was. The tubing diameter is reduced under the ferrule and it will not crimp down effectively the second time.

use the proper size hose for the fitting, no reducers. You will lose cooling efficiency.
Nice job.

What do you suggest when you are connecting condensers in series and the outlet of the first is #6 and the inlet of the next is #8?
Thanks,
Dave

As long as we're on an AC thread, I was wondering what sort of numbers folks are shooting for on the high and low side after converting to R134a? I had my Carrera converted a few months ago (but not with exchanging to barrier hoses), and I'd like to keep track of these as well as the outlet temps achieved.

I can see a total rebuild of the system coming up as a winter project, and like seeing the additional condenser threads.

Hi Jack,
Here's some average good numbers:
low 25-35 PSI, High 180 PSI OAT 90 degrees vent temp 38 degrees @ 1500-2000 RPM. Windows closed fans speed high.
Good luck,
Dave

My question also.

The only "bridge" I found was a #8 hose with a #6 fitting. I was going to run 8 hose the whole length and step it down. Happily, that wasn't necessary, and I ordered more 6 hose and fittings This afternoon.

Nice work! That S-brace is clever; no stress points and it will isolate shock and vibration from the condenser. And you'll probably get much improved performance from the OEM deck condenser with all that crap removed! RE: the washer tank, I deleted mine and ran a bicycle water bottle & cage in the trunk, near the pump. You'll never need that much washer fluid!

Today I crimped my first hoses. The hardest part was getting the fittings onto the hoses (then I figured out putting a little oil on them first. I had enough stuff on hand to make twohttp://forums.pelicanparts.com/uploa...1434334891.jpg

Was also able to extract the front condenser, it and a lump of debris as well

http://forums.pelicanparts.com/uploa...1434334980.jpg

Hey Dave, glad to see you checking in. That's a good idea on the washer reservoir. I almost never use mine.

As you can see, I decided to keep the deck lid condenser. I spent at least an hour fabbing that brace. Lots of trial and error. It does look pretty cool. The ironic thing is, all that stuff is shoehorned in there so well, it's almost unnecessary.

I also decided to go for an updated evaporator, and ordered one from our host. Also ordered a bunch of #6 hose to connect the front and 993 condensers, and uprated evap blower fan from griffiths.

Was going to start extracting the evap Box but ran out of time. I'll have to remove my stereo amp first, which means no tunes for the remainder of the project. Next weekend...

My oem setup was #8 all the way to the front condenser with a reducer at the end. Of course, I wasn't real happy with its performance...

Thanks for posting this Dave M. I'm going to need this same info in a few weeks. Also, here is some related info I cribbed from a Charlie Griffiths post:

I think the high side is somewhat influence by the effectiveness of your condensers, fwiw.

-----------

Hi side 134a pressures vs temp


80-85F = ambient times 2.4 X 1.05 or the + 5% rule
86-90F = (ambient times 2.4) X 1.1 or the +10% rule
91-95F = ambient times 2.4 X 1.13 or the +13% rule
96-100F = ambient times 2.4 X 1.15 or the +15% rule
101-105 = ambient times 2.4 X 1.17 or the +17% rule
106-110 = ambient times 2.4 X 1.20 or the + 20% rule

Here is how you apply the rules:
Say you have charged the system with a known quantity of R134a refrigerant (grams or ounces or whatever) and the ambient temperature is 95F. Take 95 and multiply it by 2.4 = 228 psi and then multiply that by 1.13 = 258 psi. Now consider if you really had this pressure well that would be in a perfect world. Depending upon whether you parked on black asphalt or if the expansion valve was opening or closing this mean target of 258 might swing up to 270 or so and frankly that is pretty good in a 911 with R134a at 95F. Or, if you are testing with the deck lid down and your services hoses are holding the deck lid up an inch or two that would reduce the effective air flow across the deck lid condenser and drive pressures upward. Other things that can drive up the high side might be the sun beating down on the deck lid or maybe you just completed a few 0-120 mph test runs up and down your driveway (like I do).

I was doing 148 runs... until a black bear appeared in the driveway

You might wish to reconsider the placement of the 993 condenser rather placing it in direct sight of the engine/exhaust/CATALYTIC converter.

You can easily verify for yourself how much adverse effect your current placement has.

Paint a partially full, <25%, can of R-134a flat black and connect it to your guage set.

Let the can acclimate to the atmospheric temperature and note the pressure.

With the engine/exhaust/catalyst "warmed" to normal operating temperature place the can inside the fender well in what would be the approximate center of the new condenser.

After ~5 minutes note the pressure....

PS: I can't tell for sure from the pictures but you seem to have the condenser installed 90 degrees from optimal insofar as preventing the refrigerant oil from pooling at the bottom of the tubes.

Nathan,

Don't fret about the minor heat your fender condenser might see from the cat.
Many people have designed their own fender condensers and the AC improvement gain you will see is excellent.

You have a 10"? fan in your design, a 12" would be better.
Put the fan on the outside of the condenser, not on the cat side.

Griff

When I replaced my hoses I simply had to loosen the tank. It moved enough where I could slip the hoses by. I recommend powerwashing the inner fenders before doing this as that washer tank holds a few lbs of dried mud up there.

You do not have to loosen or remove the washer fluid tank.

When installing a new hoses to and from the front condenser you simply
duct tape the two hoses together, insert above the bottle on the inner fender wall side, slide them forward, go underneath with a pair of safety glasses, a light and coat hanger and pull them down and through. Just be aware of the wires for the front indicator lights.

"Flat" blade fans can be readily reversed and with equal effectiveness.

"Swept" blade fans lose effectiveness in "reverse".

The fan you picture should "PUSH" when turning CCW looking at/from the motor side.

The swept or curved blades are indeed directional, but you can sometimes reverse the polarity and flip the fan blade over. Some fans do not allow this.
Good luck,
Dave

As of yet I have not found a thin enough ("pancake" motor) one that can be "flipped" over. Another aspect is that sometimes the motor brushes are "displaced" in relation to the PM "stator" and therefore favor the "native" direction.

I have used several fans from this company FDynamics, and they are very high quality and reversible by flipping the fan blade.

FF Dynamics 12" Ultra Electric Cooling Fan FFD12 | FF Dynamics

Dave

Looks exactly like one I have tried and the fan hub is molded around the motor....so I don't how it can be reversed.

Emailed a question to the vendor.

The fan is held onto the shaft with a nut. You unscrew the nut and pull off the blade. Then flip it and reinstall it.
Dave

Yes, I know... have you actually tried it...?

On my 928 I had to reverse one of the fans to make it a pusher. The big one. Worked great.

http://forums.pelicanparts.com/uploa...1434404360.jpg

Dave

Opening a new thread...