Question:
I've got a few questions about car air conditioners
How much power does the typical car A/C unit consume? I've heard
figures of 5-10 hp plus. Anyone know specifically the capacity of a a
Holden Commodore unit? In ours (VYII N/A Calais), there seems to be a
sudden surge of power from 3,000 rpm, especially noticeable in first
gear, but not necessarily with full throttle (probably half or so).
We've had a few of these cars and I don't recall any previous ones
doing this. Is this because of some sort of change to the ECU, or is
it just the A/C disengaging to give extra power?
Answer:
The VL has a similar power surge around 3000rpm. Noticeable in the auto -
Huge in the manual.
I assume this has to do with power/economy curves in the ECU, and cam design
etc - ie, it has nothing to do with the a/c
The A/C compressor on the VY (or VT onwards for that matter) does not engage
or disengage, it is always on when the A/C is on.
It is a variable stroke compressor, meaning that as load increases, so does
the internal stroke of the compressor and pressure increases. As such, there
is no surge.
What you are feeling is likely to be just the powerband of the engine.
The Telstar's an auto, and I was noting the rpm today @ 100km/h - it
was more like 2,200rpm, which is quite low for a 2.2L 4-cylinder,
although the engine is quite torquey (but at the same time breathless
above 4,000rpm).
