Does anyone know if the air conditioning runs separately from the engine to not drain HP when it is on. I remember reading about this but cannot remember if this was the Subaru STI or the EVO.

Thanks

 

I think it does steal some HP from the engine. My EVO feels very sluggish under 3000 rpm with the a/c on.

 

that would make it either electrical or belt driven. i just glanced at a pic of the compressor in the manual and it looks belt driven to me. so it doesn't run seperate from the engine.

 

It runs off the crank pulley. But I think the clutch in the A/C compressor gets disengaged when the engine is heavily loaded.

 

most vehicles a/c disengage at WOT.

 

Then it must be the STI. I do remember reading about either one of these cars having the A/C designed so as to not draw power from the engine. I thought it was the EVO because I researched it heavily. Maybe it was the JDM version?

 

Either way you are going to draw power from the engine. Otherwise you would have a system doing work for free!

Speedlimit..

 

Yeah, exactly speedlimit.
Electrical A/C would be interesting cause the motor to drive it would have to be hefty and would draw heavily on the charging system which will drain power from the motor. Most cars turn the compresor off under X amout of load, often anything over 50% of throttle will do it.

Oh and I am a smart *** so, AC is not a motor it is a compressor.
A motor is electrical, an engine is internal combustion. You have a lot of motors in your car but just one engine.
And of course there is really no such think as vacuum on engines, it's really an absence of pressure.