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

[NathanR]

Originally Posted by NathanR

I did capture some P&T data

OAT = 85F at beginning of test
Static charge = 80 psi

Before the big blowout,

Hi = 250 psi
Lo = 65
Vent T = 55F
Charge weight = 17.2 oz

Note: I didn't have the deck lid closed or a box fan blowing on the car. Next time

Does anyone see anything troubling about these numbers? Will the low side drop once fully charged?

[Ronnie's.930]

Originally Posted by NathanR

Ronnie,

No groove for o ring. Copper washer sounds like a good idea. Hardware store item?

Thanks a ton. I was out of ideas.

Cheers,
Nathan

Nathan, interesting that there is no groove, as like I mentioned, no groove means an o-ring will not work.

The best place to check for a right sized copper washer would be at an auto parts or motorcycle store. I'm refering to washers that are used to seal brake caliper banjo fittings and so forth - a lot more pressure than the a/c system produces. But that said, a hardware store with a good fastener selection might have them, too.

And regarding the above numbers, put them out of your mind as they are meaningless since you did not have air blowing over the rear condenser.

[NathanR]

Also, is there a consensus on the doors open vs closed? Seems like if your vent temp measurement are to be comparable from one moment to another you need to keep cabin temp constant, otherwise you're introducing a lot more variables than just cooling rate in the Evap coil and you would need to subtract out the ever changing cabin temp.

[Ronnie's.930]

^^^

Doors closed and windows up for me, as I am trying to establish "real world" conditions when I charge the system.

Griff recommends this technique as well.

[NathanR]

Originally Posted by Ronnie's.930

Nathan, interesting that there is no groove, as like I mentioned, no groove means an o-ring will not work.

The best place to check for a right sized copper washer would be at an auto parts or motorcycle store. I'm refering to washers that are used to seal brake caliper banjo fittings and so forth - a lot more pressure than the a/c system produces. But that said, a hardware store with a good fastener selection might have them, too.

And regarding the above numbers, put them out of your mind as they are meaningless since you did not have air blowing over the rear condenser.

I can't say thanks enough...this whole project would hAve been inconceivable with your's and everyone who has posted useful info on this over the years.

[NathanR]

Fwiw, I was encouraged by the ~30 F delta T across the coil... I think that's close to "as good as it gets" right?

[Ronnie's.930]

No problem - am glad to help (along with the barb slinging, buttofcourse)!

30F evaporator coil temps = excellent, in high ambient heat environment!

[Wavey]

Originally Posted by NathanR

Ronnie,

No groove for o ring. Copper washer sounds like a good idea. Hardware store item?

Thanks a ton. I was out of ideas.

Cheers,
Nathan

Your local NAPA, AutoZone etc. (or even WalMart?) will have copper &/or aluminum oil drain washer assortments - something from one of those might fit.

[NathanR]

I just ran to OReilly and everything they had was too big. Will check Napa tomorrow. Wonder if alumininum will work? Found that at HD.

[Ronnie's.930]

^^^ Aluminum would be fine - I've seen probably has many brake banjo seal washers made of aluminum as I have made of copper.

You'll have to use your own judgement about the "tightness", obviously, but don't be shy with it (BUTT not so tight that you pull the threads out, of course).

[NathanR]

Today I took apart the errant service port adapter and discovered there was a groove for an o ring on the adapter side, though very slim. I refitted the pressure switch and managed to screw the thing together without the ring squishing out.

[NathanR]

Then I vacuumed out the system for another 3.5 hours. Then started charging. This time I closed the deck lid with a towel to protect gauge hoses and had box fan pointed at the car.

Starting OAT = 81F
78 psi static charge.
Hi P= 252
Lo P = 26

I added 42.2 oz R134a

Vent T w. Window and sun roof open = 46F

Temps were still falling and the cabin felt pretty chilly so decided to go for a drive. Carved some turns on my favorite neighborhood twisty.

Vent T w cabin closed and tooling around town =



While happy with the results, I'm wondering if I added too much freon?

[NathanR]

And by the way, the Kuehl Evap blower fan really works well. Each of the fan speeds produced noticeable airflow, with stock resistor pack fan control setup. The max setting was very robust.

[DaveMcKenz]

Very nice. What RPM are your pressure readings taken at?
Dave

[NathanR]

Idle.

[Wavey]

Had a couple of Moose Drools after work with fellow Carrera owner Jamie and thought of you.

So, are you more or less finished?

[NathanR]

May need to let some out.

Also, I seem to have developed a fuel leak on the right side of the engine!

[kuehl]

Originally Posted by NathanR

Starting OAT = 81F
78 psi static charge.
Hi P= 252
Lo P = 26

I added 42.2 oz R134a
I'm wondering if I added too much freon?

Overcharged, maybe.

In a perfect world, at idle:
R12 at 81F running, high side target would be 194.4 psi.
For R134a it would be close to that of R12, say 204 psi

[DaveMcKenz]

If overcharged, why is the low side pressure only 26 PSI?
Thanks,
Dave

[kuehl]

Originally Posted by DaveMcKenz

If overcharged, why is the low side pressure only 26 PSI?
Thanks,
Dave

Just because a system is 'overcharged' does not mean the low side will rise proportionally.