A/C system not keeping up

[tblackey]

Has anybody else experienced this? It seems the A/C in my car is just marginal. It definately is blowing cold, but does not seem to put out that much air. It works fine in 75F weather, but when the temperatures get to 90F or above you still cook.

If it's just my system I'll look for a cause, or are all the systems this way.

GTR FWIW.

Bill

[crafty]

Are you running the Ultima compressor?

[tblackey]

No. Sanden, but I had similiar performance with the SBC and the Ultima compressor.

[Steve_D]

The problem as I see it is that my system will freeze my legs and nuts to the point of discomfort but the heat soak from the rear bulkhead still leaves me bodily overheated. Have had thoughts about ducting cold air to blow up the back of the seats but have not come up with anything that is easy to achieve and still looks the part.

First test for your system is to measure the temperature of the air coming out of the vents. As a guide my old Range Rover (Currently morphing into a Dakar)lists outlet temps of:-
Cool day (70-80F) outlet 35-40F
Warm day (80-90F) outlet 40-50F
Hot day(over 90F) outlet 45-60F

Steve

[actuary]

I use the air con whenever I am in the GTR and yes, I agree that it does drop off as temperatures rise. Not sure why; it's a new car and new unit.

On the way home from the FOD the benefit was negligible and cockpit temps soared. Very uncomfortable.

Perhaps the sun on the huge windscreen section is the culprit (plus the black interior and ally panels). I'm looking for a sunscreen to put over the top and the factory say that this does help a lot. Will let you know how I get on ...

Tony.

[XTR2Turbo]

I don't think it is thermal gain. I think most likely is the heat soak from the engine into the condensor.

I tested my car when cold and the air con will blow at 4' but it feels marginal when on a long run.

I also think the air blower is not as powerful as it could be

[NDS]

I assume your system is running on R134a. Some of the work I have been evolved with required a retro fit to R413A (RX49) this is a drop-in for R12. We found it very efficient in comparison with R134A. This may not be available in the US to its inability to comply with the SNAP program. But try one of the R12 drop-ins

[crafty]

I haven't hooked my AC up yet, but IIRC from discussions with Jeff, the fan on the condenser is activated by the thermostat and he'd wired his to run continuously, which helped.

[GTRCLIVE]

Silly question but are you sure the heater engine water value is shuting off properly....

[GTRMikie]

NDS said:

I assume your system is running on R134a. Some of the work I have been evolved with required a retro fit to R413A (RX49) this is a drop-in for R12. We found it very efficient in comparison with R134A. This may not be available in the US to its inability to comply with the SNAP program. But try one of the R12 drop-ins

I apologise for being a bit dim, but what is a "drop-in"?

[crafty]

GTRCLIVE said:

Silly question but are you sure the heater engine water value is shuting off properly....

... when JEff and I were on power tour the AC started getting REALLY hot, we thought it had broken. When we stopped we found that something had bumped the heater valve and opened it slightly, so it was fighting the heater.

We ended up blocking off the heater altogether and the AC went to arctic freeze mode.

[Builder]

GTRMikie said:

I apologise for being a bit dim, but what is a "drop-in"?

I believe "drop-in" is being used to indicate a direct replacement without any other modifications.

[tblackey]

Any known issues with just disconnecting the heater all together? I've never used it, and probably never will. I take it the AC unit shouldn't care?

[NDS]

Drop-ins

The original R12 (CFC) systems ran with mineral or alkylbenzine oil. R134a (HFC) only worked with ester and PAG oils. The drop in refrigerants were deigned to offer a non ozone-depleting alternative to R12 (CFC) AND are compatible with mineral and alkylbenzine oils. One the advantages of the HFC based drop-in as a small increase in cooling capacity.