A&Q about 350Z
Q:
You've evidently never done much work with Frigidaire A6 compressors
17 hp is common for some of their bigger ones, and some larger 70's American cars use TWO of them.
A:
In a small modern car yes, but I know of some early American cars that had compressors that needed as much as 70hp to drive them, thats more power than my 1st car produced.
Of course A/C technology has changed a lot since then
A:
Newer cars are equipped with electronic throttles and variable displacement A/C compressors. With the help of variable displacement the compressors can be connected to the engine most of the time the compressor is used. Heat removal is controled by changing the displacement. Power loss is compensated with help of the electronic throttle. The pressure in the A/C system is used to calculate how large the compensation must be. A variable displacement compressor isn't turned on and off so many timed but when it is, the electronic throttle and ignition timing is used to make the connection/disconnection smoother.
Older cars with constant displacement compressors tend to do turn the compressor on and off several times to control the heat removal. During full load they were usually turned off. No or some compensation was used. When compensation was used this was to allow for a smooth connection/disconnection.
A modern compressor like a Sanden SD-7 series takes about 8 hp or less. This is enough for a large modern car.