How often does your AC compressor cycles?

[luckyforrest]

Hi all, I have a quick question here: when you turn on AC in summer, how often does the AC compressor cycles? Mine cycles pretty frequently, the compressor engages for about 9 seconds and pause for about 4 seconds, and cycles like that. How often does your Mirage compressor cycle in summer? Thanks!

[7milesout]

LF - Just to keep everything apples-to-apples, maybe we do this cycle check with settings on something specific. I'm thinking Max fan, Recirc. Is that the settings you were on when you did the cycle time in your post above?

I'll check the Blueberry when I can. It's usually gone until midnight or so. My son will be using it for about another week.

[luckyforrest]

LF - Just to keep everything apples-to-apples, maybe we do this cycle check with settings on something specific. I'm thinking Max fan, Recirc. Is that the settings you were on when you did the cycle time in your post above?

I'll check the Blueberry when I can. It's usually gone until midnight or so. My son will be using it for about another week.

Hi 7milesout, the setting I used was max cold, recirculation, and fan setting at 2 (max 4). Today the ambient temperature here is about 94 F, humidity 49%, and I noticed the compressor stayed on for longer time especially for the first a few minutes, it stayed engaged for probably 3-4 min before the first pause, and paused for 4 seconds, and kicked in again for probably 1 min or so and paused for another 4 seconds. So the length of time it stayed engaged seems dependent on ambient temp. Once the center main vent airflow temperature dropped to 6.5-7.5 degrees Celsius (at idle speed, ~750 rpm/min, directly under sun) the lowest temp it reached today. Then it started to resume the 10 seconds on and 4 seconds off cycle again. I am happy of the vent air temperature at idle speed, and guess the 10 seconds on and 4 seconds off cycle is probably normal once it reached the lowest temp.

[spiritorb]

This frequent cycling of the compressor is normal. My 2019 ES does the same thing, especially if I have the AC dial set on the coldest position and the fan on high. It does take a while for the interior to cool down on very warm days. My AC does blow as cold as a system this tiny will allow. The only quirk about my AC that I notice is when I have the fan set to high, and the compressor and cooling fan activate together, the fan speed will momentarily drop due to the current draw from the AC clutch and cooling fan co- activating.

[luckyforrest]

This frequent cycling of the compressor is normal. My 2019 ES does the same thing, especially if I have the AC dial set on the coldest position and the fan on high. It does take a while for the interior to cool down on very warm days. My AC does blow as cold as a system this tiny will allow. The only quirk about my AC that I notice is when I have the fan set to high, and the compressor and cooling fan activate together, the fan speed will momentarily drop due to the current draw from the AC clutch and cooling fan co- activating.

Thank you. That makes me feel better. The AC compressor and cooling fan always activate together regardless of the fan setting. Have you checked the vent airflow lowest temperature it can reach?

[spiritorb]

No, i have never actually checked the temperature at the vents. To me, the AC seems to be cooling correctly.

[7milesout]

I'll check mine when I get it back.

[luckyforrest]

I'll check mine when I get it back.

Thank you very much! Could you please also check the lowest pressure at the Low port while compressor kicks in?

[7milesout]

Yes, that's a fairly reasonable parameter to use as a guide. I'll do it on a fully warmed engine, after driving some miles. Gonna be a week or two before my son is done with it.

[7milesout]

luckyforrest - I went out of town this weekend in The Blueberry. In both directions I blasted AC. When I got home I let the car idle in the driveway long enough to pop the hood and confirm the following:

At idle, my AC compressor does not cycle. It just keeps on going. That is with it on Recirc, and max fan and me visually watching the compressor clutch. I adjusted it to other fan speeds and it just kept going. I had my son manually push the AC button and I watched the fan clutch and could certainly see it stop. Then start again when he pushed it again to turn it on.

One thing I noted that I didn't expect, is that cruising along at 70 mph, it *sounded like the AC system was turning off then back on somewhat slowly. However, I couldn't feel any difference in the inside cooling, no difference in the running of the car (I can feel a small jolt when the actual compressor starts / stops). So I'm guessing that what I was hearing at 70 mph, was the cooling fan cycling. I.E. with it doing 70 mph the ECU found the coolant temp low enough to turn off the fan. Once turned off, the load on the engine + the load due to the AC running increased the coolant temp (regardless of the air through the radiator at 70 mph) to the point the fan was commanded back on. It was 90°+ and the car was running 70 mph cruise full AC, right at the car's GVWR. So, it was working ... and STILL got over 40 mpg! Helluva machine for $11,400!