Idle drop when AC compressor kicks on

[jim97gst]

I think that my idle has always dropped a few hundred RPM when my AC compressor kicks on, but I'm not positive. What I do know is that with motor mount inserts, when the idle drops below ~900 RPM, the car shakes a whole lot.

I set my idle at 950 via dsmlink. Is it normal for it to drop when the AC compressor kicks on? Is there any way to prevent it?

 

[96gsdsm]

The reason your idle dropswhen the AC comes on is because your alternator has to work harder to provide the extra voltage, thus taking some power from the engine and dropping rpm's. Every car does this to the best of my knowledge. It isn't completely unpreventable, but you could de-crease the ammount of rpm drop by adding in a high-output alternator.

 

[RyanTSi]

Normal occurance.