Air Conditioning test

Jack Olsen · 03:36 PM

Ambient temperature was 85 degrees. The sun was out. After sitting in the parking lot of the Lowes Warehouse, the interior of the (black on black) car got up to 106 degrees. I picked up a digital indoor/outdoor thermometer (with a probe on a wire), and proceeded to drive about 50 miles of mixed highway (stop and go) and surface street driving.

My AC was recently re-done by TRE Automotive in Burbank, and includes new barrier hoses, a Nippondenso compressor, the Performance Aire passive under-belly condenser, the stock front condenser with fan, a reasonably clean accumulator, and a new dryer/receiver. It's a R134a system.

Griffiths AC, in their "Mr. Ice Project," were able to get 33-degree output temps from a R134a system, also in 85-degree ambient temps. But using position three (high) of their system's fan, the best temperature they got was actually 39 degrees.

Now, my system could probably be fine tuned quite a bit, and my testing methods are probably less rigorous than Griffith's -- but I've got to say that TRE Automotive (and specifically Tyson Schmidt) has done a pretty good job. My best output temp from the vent was 38 degrees, in the third (highest) fan position. The output temp would fluctuate slightly, probably depending on ambient temp changes and revs the compressor was operating at, but the range was 38-42 degrees. Cabin temperatures started very high, and finally dropped to 76 degrees.

Not bad for an early 911 with R134a. I think it's a pretty good indicator that increasing condenser capacity on these cars is a worthwhile thing to do.

Joeaksa · 07-27-2002, 02:55 PM

Jack,

Sounds good, and are you happy with the underbody condensor? I am still worried about the loss of ground clearance, but that would depend on if and how low each 911 is and how the streets are maintained.

Would be interested to try this test here in Phoenix. Tried the same test last month in my "other" car here. Interior temp was 155 degrees with a white car and grey interior. Outlet temps were down to 40 degrees within a few minutes of getting on the road. This is with a R12 system using ES-12 gas and orginal hoses...

Your system is about as good as any of the older 911 will be able to get, and may be the only way to go using R-134.

Joe

Type911 · 07-27-2002, 03:27 PM

Jack~
If you don't mind me asking, I'm curious as to the total cost of the A/C re-do.
I have read about the Scotts condenser, considering that and/or the Griffiths upgrade.

thanks,
Chris

Jack Olsen · 07-27-2002, 03:33 PM

Unfortunately, I don't have a total cost, since it was done in pieces along with a lot of other work.

Here's the link for Scott Independent/Performance Aire's passive condenser.

And here's the link for TRE Motorsports.

CEO · 07-27-2002, 06:13 PM

Jack, could you find out what the total volume of 134a used in the the new system. Just curious. Thanks

Joeaksa · 07-27-2002, 07:47 PM

I priced out these parts a while ago. Believe that the underbody unit was $700 or so and the hoses were around $600. Diana at Scott's is very helpful and knows her stuff...

Anyone good with their hands can do the hoses for less than $100 if they do not mind stringing the hose themselves and then let a A/C shop do the rest.

Joe

Jack Olsen · 07-27-2002, 11:04 PM

No, I think the condensor alone is $395. (At least, if my memory is working tonight.)

Jorgeman · Jorgeman's Garage

[QUOTE]Originally posted by Joeaksa
"This is with a R12 system using ES-12 gas and orginal hoses..."

Joe--is that ES-12 you mentioned the same as FREEZE 12? If not--can you provide a little info about it? Thanks.

Joeaksa · 07-28-2002, 05:08 AM

Jack,

The price I had mentioned may have been including the installation. Feel that $395 is reasonable considering what an improvement it gives the system.

Jorgeman,

I believe that Freeze-12 and ES-12 are different but not sure. Believe that both are mixes of various gasses that are compatable with R-12 and their systems. I know that ES-12 is flammable, but then so is R-134 at pressure. If you do a search on the net on both you will come up with loads of information.

I personally feel that as long as I have 22 gallons of gasoline in the car, another 39 ounces of flammable material is not going to make a big difference. I have seen a 911 here in Phoenix using Freeze-12 and an old York compressor and he has outlet temps in the 40 degree range and is very happy with the performance.

Joe

07-28-2002, 05:43 AM

Jack,
Do you thonk the front condensor is necessary with the underbelly installed?
Mark

Joeaksa · 07-28-2002, 07:00 AM

Mark,

That brings up a really good question! Put the underbelly condensor on the car, pull the front stock condensor out of the front and put your oil cooler where it should be and would get some real airflow.

I would really be interested in doing that if it would work out....

Joe

07-28-2002, 07:14 AM

Joe,
That's what I was thinking plus I see 3 positives of removing the hood mounted condensor from the engine compartment:

-less air restriction for better cooling
-the air entering won't be pre-heated from the condensor/heat sink also for better cooling
-less clutter in the engine compartment

Are these correct assumption?
Mark

Joeaksa · 07-28-2002, 09:24 AM

Mark,

I was talking about taking the condensor off the front of the car, and believe that you are talking about taking the one off of the rear of the car.

Patrick Motorsports here in Phx does just that, and installs a 993 or 996 condensor in the left front fender, with a fan. Says it works great but do not know anyone who has one.

I would feel that taking the motor unit off could result in good temp savings (cooler into the motor) and would also love to take the front one off and relocate the fender mounted cooler there as well.

Joe