Motor driven ac compressor btu output and hp needed
 

Anyone know the btu output of a motor driven 911 ac compressor? Also what hp is required to operate it at maximum output?

On a related thread, someone indicated that the Classic Restoration compressor draws about 80 amps when running. Let's use that as a representative example.

80A x 14V = 1160 watts. 1160W = 1.55HP.

Add 10% for conversion losses, and it should take about 1.7 HP to run the compressor.

Depends on the compressor. I run a SD5H14 8ci
This is pretty similar. Right at 7kW max so closer to 8-10hp. I see a 50RPM drop when I turn the AC on at idle so my idle is set somewhat higher to compensate. On my turbo I don't feel that loss...but I do like the mid 30s vent temps!
Most peeps don't go this big.... but you need kW to cool. :)
http://forums.pelicanparts.com/uploa...1690553673.jpg

Just seat of the pants feel and no science at all:

I have the factory stock style of compressor, the Nippendenso. It is new as I wore out the the second one after many years of use.

Anyway, my idle does not change at all with the compressor cycling on or off at idle. I do not really notice it in driving, but I do understand, yea, it is using some HP to compress the refrigerant and make cold air for the cabin.

I would have to guess, maybe a few HP, but not a lot.

And my AC system if the full boat, Mr. Ice setup from Griffith's with 4 condensers, and extra vents, and added knee vents for the tiny 85 Carrera side vents. I can get 37 degree air blowing at the MAX hurricane speed when it is 107 outside after a 11 hours of driving, or just 10 to 15 minutes after sitting for an hour in the sun. I don't worry about the HP loss as it is minor.

Correct. The stats I posted for that big Sanden are at MAX RPM. That's almost never so the normal HP drag depending on compressor is in the range of 3-6. Who cares....

I think it might even be less than 3-6 HP with the stock Nippon Denso.
The small magnetic clutch draws only 3 amps and I doubt it would pass the torque required for 6 HP (that is more than 4kW). My compressor belt is not even tight and I never hear it squeal when AC is on.

If i use an electric compressor say keep it in the rear with stock everything then 3 hp to 6 hp? Up to 372 amps?
Guess that is not going work as i would a 500 amp alternator?

Trying to equate the mechanical pump HP to the electric one is the first mistake. Trying to use an electric pump with 'stock everything' will be the second.