So before you ask, compressor, condenser, and a A/C kit have all been replaced, it has the exact amount of refrigerant needed, and theres no leaks. Running a mishimoto radiator/condensor.

Im not sure if this is just G thing, or what, since the G's dont have a "max a/c" button, but has anyone ever noticed that the A/C in the vehicle doesnt perform amazing, like I get better A/C out of my gfs 14 altima than my own car.

If there is some kind of fix or trick or something for these cars, let me know, cause its getting in the high 90's and im looking to freeze my *** off in the car rather than feel "comfortable"

 

Car needs to be moving and tint helps (Ceramic is best), but that's true with any AC.

Mine gets so cold sometimes I feel like I'm forming an ear ache. But sitting in traffic, mid day with the sun shining in the windows, it has to work harder and doesn't get as cold, even when recirc is used.

 

Can only speak to the performance of my 2008's AC...

With temps lately in the mid-90's (heat indices in the 100's) mine cools strong. My car is not garaged so it gets full sun. After the first 10min. or so at 60 (on AUTO) I will have to gradually increase the temp to 69/70 where I keep it. Even after the RECIRC door opens (allowing outside air in) the AC is still cold. Only when I had fan issues years ago (where they were both dying) did my AC never blow ice cold.

I will say this much, it blows a hell of a lot colder than my 2014 BMW on "MAX" and that is only a 2-seater!

Are your blend doors working as they should? Verify if the fresh air door is sealing tight agains the inlet flange (when in RECIRC). Other than that maybe it is just the nature of your car. Not intending to come off snide, but it seems this car has always had some sort of issue with its AC system, no?

 

socketz; i understand driving = colder, also i do have tint just not ceramic, so still gets toasty lol (black on black car), but im sure you get what im saying though, some other cars just tend to have a stronger a/c, even at idle, so maybe its a G thing, if anyone else has this same kind of experience with the vehicles

ilm-nc; id have to verify if my blend door is working as it should, i honestly couldnt tell you, and i wish i could give you a real temperature reading to try to get an idea of what im saying into words, i always keep the a/c at its lowest (60) but it never actually feels like 60, im not freezing, my gfs altima though, blows like a champ, its crazy how it works, so thats why im just confused.
is the blend door easy to get to? How would I know visually if its working as intended

and yes, ive always had a/c problems lol, but I have fixed the "real" issues (compressor) and improved what i had (a/c kit, new condensor/radiator, proper lbs of freon + vacuumed)

 

With KOEO you should be able to hear the fresh air "door" cycling as you press the RECIRC button. To visually test- and ensure the door is sealing tight against the flange- you'd have to remove the cabin air filter. It just sounds to me that warmer air is slightly mixing in somehow. That is the bad part about modern cars- hot water is constantly circulating through the heater core thereby allowing some level of residual heat soak into the cabin.

The HAC section of the FSM shows the self-diagnostic for the HVAC system though I will warn you it is not the easiest to navigate. This function will allow you to check all the blend doors (not just the fresh air), the various sensors, and if any codes are stored in the AC Amp (these codes are independent of OBD2 and thus will not show on scanners). You should also be able to adjust the temperature trim settings:

Just tossing out ideas...

Next time I go out (likely next week after this holiday headache) I will bring my thermocouple with me and measure output temps. May or may not help but...

 

Definitely a G thing. The exhaust is right there, next to your leg, and the heater core always has flow.
the AC works fine but its fighting two active heat sorces.
Three if youve got an automatic transmission.
imagine what those turbo boys are dealing with, heat management wise.
Here's what I did about it;
Bypassed the heater core. (You can use ball valves if you want)
Ditched the cats.
Added peel and stick insulation under the carpet, around the trans tunnel.
Added additional tin heat shielding under the floor as well.
Spray and stick foil isulation between the headliner and roof too.
​​​(Pro-tip, dont black out the roof)
Overboard, maybe, but my
cab temps stay down. Even in the florida summers

I also have ceramic coated and wrapped long tube headers.
Deleted coolant lines at the throttle bodies and oil filter.
Extenal coolers with thermostatc fans for my engine oil, trans and supercharger.
Deep, finned oil pan.
My engine temps stay down even in traffic.
Oh yeah, i also opened up my side grills in the lower front bumper for more air flow, but thats because of the supercharger and extra coolers.
Didn't want to stack the coolers in front of the radiator/condenser/intercooler sandwich.

 

Well, after 30+ years my trusty Fluke multimeter finally decided to give up the ghost. So, as I had to get another unit and I know I don't have another 30 years in me I went with a basic one. Tomato / tomahto...

As I said I would here are some readings from today's trip. I tried to take pics with the clock to show passage of time relative to temperature change. All temperature readings are in Fahrenheit (°F).

Unlocked the car and the internal temp was 116° and outside ambient 93° (not including humidity/ heat indices):




Car at stationary idle with temp dial set to 60°/ AUTO/ fresh air OFF the outlet/ vent temp was 57°. At this point all 3 fans were at 100% duty doing their thing:


At highway speed vent temps dropped to 54°:


After approx. 30min. changed temp dial to 69° still on AUTO and fresh air OFF. Cabin air temp (as measured by the center console/ shifter) was 72°:


Arrived at final destination (total trip time just under 1-hr. w/ mixed 60/40 hwy/city/ bloody tourist traffic) the cabin temp was 69°- which is what I had the dial set to on AUTO with fresh air OFF:


Again, not sure how helpful this is but it satisfied my curiosity as to AC efficiency with my G ('08/ Coupe/ 5AT).

If I get so inclined I'll likely do the same "test" on the Bimmer though I know the AC on that car just doesn't feel as effective and it's only a 2-seater. Then again, it was designed to be driven topless so I guess BMW didn't "over engineer" the HVAC on that car. Tomato / tomahto.

Hope this helps someone down the line...

 

Mods... As the following is not directly "G37-related," move or delete as rules may require...

So, for Schlitz and giggles I decided to repeat the above AC temperature test on the Zed/4. I always felt that the AC was not "quite as good" as on the G37 and while I am comparing a apple to a orange (almost literally) turns out I am not as nutty as I thought.

Internal cabin temp was 137º and outside ambient was 95º (though gauge cluster said 94º). Heat index was 101º per the weather app on the iPhone. Miserable to say the least.



After a few minutes with car at stationary idle, with the AC set to "MAX AC" the temp at the outlet vent was 75º. Important to note, the Zed/4 only has one, large radiator fan and while it was at full duty, the temp at the vent was ≈20º warmer than the G37 at the same point in this "test."

After ≈10min. at highway speed the outlet temp dropped to 55º. The extra air flow across the condenser made the difference here. I am assuming the radiator fan pushes "just enough" CFM to keep things going.


After ≈30min. or so I switched to AUTO and turned the temp dial to my usual 69º. This takes the system out of "MAX AC" but outside of the cabin blower slowing down nothing really changed. Cabin temp was 86º.


Arrived at final destination. Total trip time 1hr. 27min. at 70/30 highway/ city/ tourist traffic (one small fender bender held up traffic for about 10min.). It was definitely hot as engine oil temp went as high as 245º at one point (normal for me is ≈230-235º). Final cabin temp was 78º despite having the dial calling for 69º.


Key takeaways... for one, I am comparing a Japanese Coupe to a German Roadster so take that as it is. One would assume because the cabin is super small compared to a Coupe or a sedan that it would cool faster. Nope. The BMW has a "all black" interior save for the orange pieces and we all know black holds heat. So, perhaps it takes longer for the AC to remove all of that stored heat in all the black plastic trim- and there's tons of it. Then again, the car is a roadster so perhaps BMW just put in a basic system figuring most people drive the car topless which I do when its not searing hot outside.

However, when its 83º at 1am its almost perfect for killing the AC, dropping the top, blast Coldplay's "A Sky Full of Stars," and just take it all in:


Not the best moon shot, but I wasn't exactly stationary The "red stripe" is the guard rail on the road with the tail lights reflecting off.

 

Can we assume your cabin air filter isn't dirty? That it isn't a aftermarket hepa style filter? Too thick and it does block airflow. Park in the shade, if you can. You'll notice the difference right away when you start with an interior that was exposed to directly to the sun. It does take forever for the G to get cold when the interior is super hot. I noticed this years ago.