yajstylez

My car has been replaced with a whole new a/c system (pretty much new everything besides the hard pipes) and my a/c still isn't as cold as I'd like it. Blowing roughly, at lowest, 62-65 f on idle (car fully warmed) in a 100 f day and only getting anywhere from 55-60 f during cruising speeds and even on freeway. Only gets into the high 40's if driving on freeway for a good while. Low pressure side holds 50-52 psi pretty steady (which is in range of the chart) but forgot the high side psi.

I want to add a slim pusher fan in front of the condenser (to keep a/c cooler at idle/red light, even if it's just a bit cooler; those 105 f days are no fun) but also wanted the fan to turn on/off only when the regular a/c condenser fan turns on as well (don't want a manual switch). How do I go on about that?

2001 Honda Civic LX Coupe

OneJzSupra

It might not get as cold while at idle due to the compressor not spinning as fast, one thing I've considered trying is insolating the AC lines to help prevent heat soak. now before any one says anything like why would I need it I live on Guam.... which is like hot as **** all year long. We only have two seasons here.... hot and typhoon season lol.

cja3455

I don't think another fan would help much; make sure all the door seals are in good shape and lubricate them with shin etsu grease and have the ac circulation switch on when the ac in on; that helps a lot in hot temperatures

ezone

IF your ambient temps are 100 + degrees F, that vent temp reading is well within reason. Pretty damn good, actually.

pjb3

If I understand you correctly, you want the A/C to put out air at a specific temperature such as 50 degrees at idle.

The A/C does not put air at a specific temperature, it drops the temperature of the air passing thru the evaporator by removing a certain amount of heat. In other words, the air coming out of your A/C will be 15 to 30 degrees cooler than the air entering it depending on temperature and relative humidity. If you recirculate the air, the temperature coming out of the vents will get cooler as the inside of the car gets cooler and the humidity drops.

OneJzSupra was also correct that at idle the compressor is not at optimal speed.

yajstylez

Oh I see. And yes, I only use non-recirculating a/c because I only want fresh air. If the temperatures are really within reasonable specs, then thank you for the information. I've read many threads googling for a/c idle temps and many say 'ice cold' even in 90-100 f but I guess they might of also have been using the a/c in recirculating mode though (as some of them mention; not entirely sure if they all are).

*Looking forward (info at least) to insulate a/c lines.

And regardless, I really don't like recirculating air (traveled many times with recirc air and it gets me sick easily) so how can I still connect an extra fan and have it turn on and off with the stock a/c control unit (or when the a/c condenser fan turns on)? *Again, without a manual switch.

ezone

Agreed.




I only expect about a 20 degree (F) drop when air passes through an evaporator core one time.
If you only have 100*+ air entering the core, then you won't feel much cooling effect at the vents.

If you use recirculate, then air that has already been dried and cooled can be cooled again, and the temp drops more and more as the interior air is cooled over and over. It's simply more efficient for the system as a whole.

Same effect: Would you have all the windows wide open while running your AC? In your house?

OneJzSupra

Being a person who has lived underwater for 6+ years (submarine) I can tell you now that recirculating air shouldn't make you sick. While "recirculating" fresh air still makes it's way in since your car isn't air tight.

yajstylez

Just tested the a/c with recirculating mode yesterday and the cooling is about exactly the same as without (100 f yesterday). Both idle (left my car idling from cold start for a good 10-15 minutes while getting dressed; was roughly around 67 f when I got in the car from the vent; car in itself was still hot!) and driving had no difference in coolness with recirculating on or off. (Used a meat digital thermometer). Something definitely wrong here?

ezone

I believe you may be expecting more than the car is capable of.
The AC system is barely adequate for the size of the car as it is.



I'll say your descriptions above sound "normal" to me.

1) The compressor is simply not efficient at idling RPM, therefore higher vent temperatures.

2) Solar load heating of the cabin can outpace the AC system, especially at idle. Worse if the car paint is a dark color, worse again if the interior is also a dark color.

3) On a 100*+ day, the temperature in the interior of the car can be well above 180 degrees F.
It can take a long time to cool down that interior, that's why I open all the windows-- along with turning on the AC -- when I first enter a hot car and begin moving. It's far more efficient (faster) to let fresh air remove the first 80+ extra degrees than it is to wait for the AC to do it.

Remember too: Not only is the air temperature inside the car hot, everything in the interior is also hot and radiates heat. The fabric, the plastic and the metal all retain and continue to radiate heat long after the air temperature in the cabin has dropped.

Copied from an 01 Civic owners manual:
If the interior is very warm from
being parked in the sun, you can cool
it down more rapidly by setting up
the controls this way:

1. Start the engine.
2. Turn on the A/C by pressing the
button.Make sure the temperature
control dial is turned all the
way to the left.
3. Set the fan to maximum speed.
4. Open the windows partially. Select
and Fresh Air mode.

When the interior has cooled down
to a more comfortable temperature,
close the windows and set the
controls as described for normal
cooling.


HTH