How well does a modern car's AC system work in a place like Death Valley?

[bohica2xo]

Lot of assumptions there Chris.

My intake picks up air from the same place the condenser gets it - in front of the core support. The mainly plastic intake tract heat soaks a small amount.

Idling in traffic surrounded by other vehicles blowing out 150+f air from their heat exchanger stacks raises the air temperature considerably. Your 100f air with 45% humidity may be a bigger challenge for the evaporator, but is easier on the condenser than 130f air @ 5% humidity.

Ground speed counts. Moving more air, even at the same temperature offers a better delta T.

And yes, occasionally at extremely high temperatures and traffic, I can run the engine speed up to 4000 rpm and see the HPCO for a few seconds. In Laughlin @ 117f for instance.

[Carguychris85]

Lot of assumptions there Chris.

My intake picks up air from the same place the condenser gets it - in front of the core support. The mainly plastic intake tract heat soaks a small amount.

Idling in traffic surrounded by other vehicles blowing out 150+f air from their heat exchanger stacks raises the air temperature considerably. Your 100f air with 45% humidity may be a bigger challenge for the evaporator, but is easier on the condenser than 130f air @ 5% humidity.

Ground speed counts. Moving more air, even at the same temperature offers a better delta T.

And yes, occasionally at extremely high temperatures and traffic, I can run the engine speed up to 4000 rpm and see the HPCO for a few seconds. In Laughlin @ 117f for instance.

In that situation it would make a huge difference in the engine/condenser fan fitted to the vehicle. I run a the largest, highest blade count, highest pitched clutch fan that will fit the shroud and severe duty fan clutch on everything. At 4,000 rpm the engine driven fan would be screaming. The engine driven fan absolutely roars when it engages with my engine turning 2,850 rpm at 75 mph towing in 3rd gear. It roars like a dump truck in traffic when it engages and the ac pressure drops enough to actually cut the system out on the low pressure cutout. A weak electric fan setup even the factory ones do not move the volume of air a good clutch fan and shroud can especially with the engine off-idle. On my van crawling along at 5-10 mph in 1st gear the engine is turning 1,000-1,500 rpm when you start off and the GM throttle cracker/rolling idle routine still idles it at ~1,000 rpm until you come to a full stop and the PCM returns to the lower base idle. IIRC in the programming it has to drop under 2 mph before it will idle all the way back down to the 750 rpm it is set at and as soon as it is rolling 3 mph or more it is back to 1,000 rpm. If the engine coolant hits 219F or the commanded alternator output reaches 80% PWM signal it will increase the base idle to 850-900 rpm as well.

When I tested my system last summer on my 97 after a compressor change and rear expansion valve replacement it was 109F officially but the condenser air intake was 115F in the concrete parking lot I was sitting in. With all the doors closed and the engine at 2,000 rpm you can hear the clutch fan roaring over everything.

https://youtube.com/shorts/d_wkF47r5Kk? ... ttlcM6Cx1R

This is the clutch fan kicking in at 75 mph at about 2,850 rpm engine speed. I had been pulling uphill for about 3 miles at that point. Instant surge of cold air and drops the pressure enough to cycle out the compressor on the dual evaporator system regardless of the hvac blower speed settings. The massive 9 bladed Duramax 6.6L fan blade I have on my small block is moving an easy 10,000 cfm at that point. The fan never has to kick in much like that but when it does it screams. I have that fan now fully PCM controlled on an EV Clutch. The PCM monitors engine and transmission temperature as well as ac pressure and runs a PWM signal to the clutch which varies from ~15% to 85% engagement and the fan turns between 400 rpm and 3,600 rpm depending on the engine rpm and PWM signal to the clutch. The EV clutch has a hall effects sensor for RPM feedback to the PCM. The fully functional EV clutch setup works alot better than the mere on/off signal I was feeding the clutch at the time that video was made using the on/off PCM control for an electric fan. The 2019 Titan has the same type of EV clutch from the factory and it works the same way. The Titan also has dual PCM controlled shutter blade setups for cold weather warmup which I am not a fan of but they came on it and will set DTCs if removed. If they end up failing I will be finding someway to bypass their presence.

https://youtube.com/shorts/xtH17jWIbHI? ... 0_u0AEcbp-